Systems and methods for analyzing nucleic acid sequences   

Abstract: The invention relates to systems and methods for analyzing clinically relevant nucleic acid sequences.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Nos. 60/493,238, filed on Aug. 6, 2003, and 60/568,958, filed on May 7, 2004. The contents of both of those provisional applications is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This invention relates to systems and methods for analyzing clinically relevant nucleic acid sequences.

The healthcare delivery system has changed remarkably over the past several decades. Clinical laboratories are under increasing pressure to deliver low cost and highly accurate analytical services with the rapid turn-around time required by physicians and patients. Laboratory testing has changed and improved in recent years to meet the challenge. Robotics has been introduced to the laboratory to increase efficiency and reduce the need for human participation, and laboratory instruments have been designed to decrease the biological sample volumes needed to perform various assays. However, more improvement in the clinical laboratory area is required to meet the demands of the ever-changing healthcare system.

SUMMARY

The present invention provides novel automated systems and methods to perform assays on nucleic acid sequences (e.g., clinically relevant nucleic acid sequences). The system can provide assay results quickly, accurately, and in a format easily accessible by health care providers and/or third party payors (e.g., insurance companies). The invention also provides novel and highly accurate assays using mass spectrometry (e.g., matrix-assisted laser desorption/ionization (MALDI)).

In one aspect, the invention provides a system for performing a diagnostic assay on a biological sample. The system includes, as its main components (a) a central controller programmed to: (i) exchange information about the biological sample with an outside system or database; and (ii) exchange information about the biological sample with one or more modules of the system; (b) a sample transfer module for transferring a portion of the sample to a first container; (c) a nucleic acid extraction module for extracting nucleic acids from cells within the portion and for transferring the portion from the first container to a second container; (d) a nucleic acid measurement module for measuring the concentration of nucleic acids in the portion; (e) a PCR preparation module for adding polymerase chain reaction (PCR) reaction materials (e.g., individual nucleotides, primers, polymerase enzymes, and reagents) to the portion; (f) a thermocyling module for amplifying a target sequence and extending a primer in the portion; (g) a primer extension preparation module for adding primer extension reaction materials to the portion; (h) a mass spectrometry preparation module for removing a sample of the portion from the second container to a support (e.g., chip or microwell) for analysis by mass spectrometry; and (i) a mass spectrometry module for analyzing the sample.

The central controller can be a computer system, e.g., a commercially available personal computer system, and can include linking software that enables the central controller to communicate with at least one other module in the system. The system can also include a plate editor module that provides sample information to the PCR preparation module, a transport module comprising one or more robotic arms or tracks to transport a biological sample, or portion thereof, between at least two modules of (a) to (i), and arranged to receive information from and transmit information to the central controller. The system can also include a detection module for detecting the presence of a sample and monitoring the progress of the sample through the system, and arranged to receive information from and transmit information to the central controller. The nucleic acids measurement system can include an ultraviolet light spectrophotometer or a fluorometer. The PCR preparation module can include a pipetting robot, and the thermocycling system can include a thermocyler. The system can further include a computer-readable medium comprising one or more programs for instructing a given module.

The PCR preparation module can include PCR materials, e.g., at least one primer set described herein, e.g., a primer set selected from among SEQ ID NOS:1 to 504, each primer set including two amplification primers and one detection extension primer. The sample transfer system can include a pipetting robot.

In another aspect, the invention provides a method of performing a diagnostic assay on a biological sample. The method includes (a) performing on a biological sample an assay using a clinical assay system, wherein the assay comprises mass spectrometry analysis of a target nucleic acid; and (b) automatically reporting information about the assay from a central controller of the clinical assay system to an outside system or database accessible by at least one health care provider (e.g., at least 2, 10, or more than 10) or at least one third party payor (e.g., at least 2, 10, or more than 10). The clinical assay system can include at least one component selected from the group consisting of: a central controller, a sample transfer module, a nucleic acid extraction module, a nucleic acid measurement module, a PCR preparation module, a thermocyling module, a primer extension preparation module, a mass spectrometry preparation module, and a mass spectrometry module.

In another aspect, the invention provides a method of performing a diagnostic assay on a biological sample. The method includes (a) receiving a biological sample, generating information about the biological sample, and transmitting the information to a central controller; (b) transferring a portion of the biological sample to a first container; (c) extracting nucleic acids from cells within the portion and transferring the portion to a second container; (d) measuring the concentration of extracted nucleic acids in the portion; (e) adding polymerase chain reaction (PCR) materials to the portion; (f) amplifying target nucleic acids in the portion; (g) adding primer extension reaction materials to the portion; (h) extending a detection extension primer in the portion; (i) transferring a sample of the portion from the second container to a support; (j) analyzing the sample and exporting data to the central controller using a mass spectrometry system; and (k) transmitting the data from the central controller to an output device, external system, or database. In certain embodiments, steps (a) to (k) can be performed automatically by an automated system. The automated system can include at least one component selected from the group consisting of: a central controller, a sample transfer module, a nucleic acid extraction module, a nucleic acid measurement module, a PCR preparation module, a thermocyling module, a primer extension preparation module, a mass spectrometry preparation module, and a mass spectrometry module.

In certain embodiments, the diagnostic assay can be an assay for detecting mutations in a gene. The gene can be a gene selected from the group consisting of: 5,10-Methylenetetrahydrofolate Reductase (MTFR); Coagulation Factor II; Coagulation Factor V; hemochromatosis (HFE); and a glucocerebrosidase (GC). fibroblast growth factor receptor 3; aspartoacylase; Glucocerebrosidase; Coagulation Factor VII; Fanconi Anemia, Complementation Group C (FANCC); inhibitor of kappa light polypeptide gene enhancer in b cells, kinase complex-associated protein; acid sphingomyelinase; hexosaminidase; angiotensin i-converting enzyme; adenylate cyclase 9; apolipoprotein A-1; apolipoprotein E; endothelial leukocyte adhesion molecule 1; fc fragment of IGG, low affinity IIa, receptor; fibrinogen beta chain; coagulation factor II, factor XIII; guanine nucleotide-binding protein beta-3; integrin, alpha-2, glycoprotein Ia/Iia; glycoprotein Ib, platelet, alpha polypeptide; intercellular adhesion molecule 1; glycoprotein Ia/IIa (a2), integrin, alpha-2; platelet glycoprotein Iib, integrin, alpha-2b; glycoprotein integrin, beta-3,3-hydroxy-3-methylglutaryl-coa reductase; lymphocyte adhesion molecule 1; methylene tetrahydrofolate reductase; plasminogen activator inhibitor 1; platelet alpha-granule membrane protein; transforming growth factor-beta receptor, type III; thrombomodulin; tumor necrosis factor; vascular cell adhesion molecule; coagulation factor II receptor; glycoprotein VI, platelet; purinergic receptor P2Y, g protein-coupled, 1; purinergic receptor P2Y, G protein-coupled, 12; prostaglandin-endoperoxide synthase 1; prostaglandin-endoperoxide synthase 2; thromboxane A2 receptor, platelet; and thrombospondin I.

In other embodiments, the diagnostic assay is an assay for detecting a pathogen in the sample, e.g., a virus, bacterium, or fungus. The virus can be a virus of the family Herpesviridae, e.g., cytomegalovirus (CMV).

In another aspect, the invention provides an method, e.g., an automated method, for detecting mutations in a target gene. The method includes a) amplifying a target sequence using PCR and performing, e.g., automatically, a primer extension reaction using a set of three primers, each set of primers including two amplification primers and one detection extension primer; b) transferring, e.g., automatically, detection extension primers to a mass spectrometry device; and c) determining, e.g., automatically, the molecular weights of the detection extension primers by mass spectrometry following the primer extension reaction, wherein a change in the molecular weight of the extended primer, as compared to a control, indicates the presence of a mutation in the gene. The method can include automatically transmitting information related to the presence of the mutation to a central controller.

In certain embodiments, the gene is a 5,10-Methylenetetrahydrofolate Reductase (MTFR) gene, and the set of three primers is selected from the group consisting of: SEQ ID NOS: 1, 2, and 3; SEQ ID NOS: 4, 5 and 6; SEQ ID NOS: 7, 8, and 9; and SEQ ID NOS: 10, 11, and 12; each set of primers including two amplification primers and one detection extension primer.

In other embodiments, the gene is a Coagulation Factor II gene, and the set of three primers is selected from the group consisting of: SEQ ID NOS: 13, 14, and 15 and SEQ ID NOS: 16, 17 and 18; each primer set including two amplification primers and one detection extension primer.

In still other embodiments, the gene is a Coagulation Factor Vgene, and the set of three primers is selected from the group consisting of: SEQ ID NOS: 19, 20, and 21 or SEQ ID NOS: 22, 23 and 24; each primer set including two amplification primers and one detection extension primer.

In yet other embodiments, the gene is a hemochromatosis (HFE) gene, and the set of three primers is selected from the group consisting of: SEQ ID NOS: 40, 41, and 42, SEQ ID NOS: 43, 44 and 45; SEQ ID NOS: 46, 47 and 48; SEQ ID NOS: 49, 50 and 51; SEQ ID NOS: 52, 53 and 54; or SEQ ID NOS: 55, 56 and 57; each set of primers including two amplification primers and one detection extension primer.

In another aspect, the invention includes a method, e.g., an automated method, for detecting a pathogen in a biological sample. The method includes a) amplifying a target sequence using PCR and performing, e.g., automatically, a primer extension reaction using a set of three primers, each set of primers including two amplification primers and one detection extension primer; b) transferring, e.g., automatically, detection extension primers to a mass spectrometry device; and c) determining, e.g., automatically, the molecular weights of the detection extension primers by mass spectrometry following the primer extension reaction, wherein a change in the molecular weight of the extended primer, as compared to controls, indicates the presence of a pathogen in the sample. The controls can include an internal control for determining the amount of the pathogen in the sample.

In some embodiments, the pathogen is cytomegalovirus (CMV), and the three primers are selected from the group consisting of: SEQ ID NOS: 25, 26, and 27; SEQ ID NOS: 28, 29 and 30; SEQ ID NOS: 31, 32, and 33; SEQ ID NOS: 34, 35, and 36; SEQ ID NOS: 37, 38, and 39; and SEQ ID NOS: 58, 59, and 60; each primer set including two amplification primers and one detection extension primer.

In another aspect, the invention includes an isolated DNA selected from the group consisting of SEQ ID NOS:1 to 504.

In still another aspect, the invention includes a kit that includes at least one primer set described herein, e.g., a primer set selected from among SEQ ID NOS:1 to 504, each primer set including two amplification primers and one detection extension primer, and instructions for using the primer set to detect or analyze a target nucleic acid sequence in a biological sample. For example, instructions can be provided to describe how to use the primers to detect the presence of, or identify mutations in, a particular nucleic acid sequence or gene. As another example, the instructions can describe how to use the primers to detect the presence of a pathogen (e.g., a virus, bacterium, and/or fungus), the quantity of the pathogen, and/or the genotype of the pathogen.

In yet another aspect, the invention includes a computer readable medium that includes a program for instructing a central controller in an automated system for performing an assay on a biological sample to: (a) receive a biological sample, generate information about the biological sample, and transmit the information into a central controller; (b) transfer a portion of the biological sample to a first container; (c) extract nucleic acids from cells within the portion and transfer the portion to a second container; (d) measure the concentration of extracted nucleic acids in the portion; (e) add polymerase chain reaction (PCR) materials to the portion; (f) amplify target nucleic acids in the portion; (g) add primer extension reaction materials to the portion; (h) extend a detection extension primer in the portion; (i) transfer a sample of the portion from the second container to a support; (j) analyze the sample and exporting data to the central controller using a mass spectrometry system; and (k) transmit the data from the central controller to an output device, external system, or database.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and equipment or software similar or equivalent to those described herein can be used in the practice of the present invention, suitable methods, equipment, and software are described below. All publications and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.

FIG. 1 is a diagram illustrating the main components of a clinical assay system and the flow of biological samples and information through the system.

FIG. 2 is a flow diagram illustrating the steps of the clinical assay system.

FIG. 3 is a mass spectrum of a heterozygous “TC” allele (heterozygous positive) generated using a screen for a C677T mutation in the 5,10-Methylenetetrahydrofolate Reductase (MTFR) gene.

FIG. 4 is a mass spectrum of a heterozygous “GA” allele (heterozygous positive) generated using a screen for a G20210A mutation in the Coagulation Factor II (FII) gene.

FIG. 5 is a mass spectrum of a heterozygous “GA” allele (heterozygous positive) generated using a screen for a R506Q mutation in the Coagulation Factor V gene.

FIG. 6 is a mass spectrum of a heterozygous “GA” allele (heterozygous positive) generated using a screen for a R506Q mutation in the Coagulation Factor V gene.

FIG. 7 is a mass spectrum of heterozygous “GC” alleles (heterozygous positive) for H63D Histidine to Aspartic acid (C187G) mutation in the FM3-E assay.

FIG. 8 is a mass spectrum of heterozygous “GC” alleles (heterozygous positive) for H63D Histidine to Aspartic acid (C187G) mutation in the HFE-E3 assay.

FIG. 9 is a mass spectrum of heterozygous “GA” alleles (heterozygous positive) for S65C Serine to Cysteine (A193T) mutation in the HFE S65C E1 assay.

FIG. 10 is a mass spectrum of heterozygous “GA” alleles (heterozygous positive) for S65C Serine to Cysteine (A193T) mutation in the FIFE S65C E5 assay.

FIG. 11 is a mass spectrum of heterozygous “GA” alleles (heterozygous positive) for C282Y cysteine to tyrosine (G845A) mutation in the FM6-E assay.

FIG. 12 is a mass spectrum of heterozygous “GA” alleles (heterozygous positive) for C282Y cysteine to tyrosine (G845A) mutation in the HFE-E6 assay.

FIG. 13A1-13A3 is a set of mass spectra in a CMV quantitative assay on samples containing 400 CMV copies/ml.

FIG. 13B1-13B3 is a set of mass spectra in a CMV quantitative assay on samples containing 4000 CMV copies/ml.

FIG. 13C1-13C3 is a set of mass spectra in a CMV quantitative assay on samples containing 40,000 CMV copies/ml.

FIG. 13D-13D3 is a set of mass spectra in a CMV quantitative assay on samples containing 400,000 CMV copies/ml.

FIG. 13E1-13E3 is a set of mass spectra in a CMV quantitative assay on samples containing 4,000,000 CMV copies/ml.

FIG. 13F1-13F3 is a set of mass spectra in a CMV quantitative assay on samples containing 40,000,000 CMV copies/ml.

FIG. 13G1-13G3 is a set of mass spectra in a CMV quantitative assay on samples containing 400,000,000 CMV copies/ml.

FIG. 14 is a graph that plots CMV plasma samples versus internal standards. A CMV control (4×109 copies per ml) was diluted down to 40 copies/ml in 10-fold increments, mixed with the Internal Standard of appropriate concentration, extracted (240 μl) on MDX (Qiagen), eluted in 75 μl of buffer and assayed (2 μl) by PCR, followed by SAP treatment, extension reaction and mass spectrometry analysis.

FIG. 15A-15GG is a table that lists a number of genetic targets for the assays of the invention, along with exemplary primers for those targets.

DETAILED DESCRIPTION

The invention provides a new highly automated system for performing clinical assays, optionally with automatic billing to third party providers such as insurance companies. The invention also provides novel assays using mass spectrometry (e.g., matrix-assisted laser desorption/ionization (MALDI). The assays are highly accurate and can detect, for example, sequence variations (e.g., mutations and/or polymorphisms) and foreign sequences (e.g., viral sequences) incorporated into a target gene. The assays are also useful for infectious disease/pathogen testing.

The entire process, or portions thereof, can be automated, i.e., performed by machine(s). Accordingly, the present invention also includes a high-throughput process for performing the assays described herein. Thus, the new system can perform dozens (e.g., 96, 128, 384) of different assays on dozens of different biological samples at the same time.

Overview of System

FIG. 1 provides an overview of the clinical assay system 2 of the present invention. The clinical assay system includes, as its main components, the following modules. A central controller 4 for exchanging information about the biological sample with an outside system or database 8 and with one or more modules or systems within clinical assay system, and an input device 6; a sample transfer system 10 for transferring a portion of the sample to a first container; a nucleic acid extraction system 12 for extracting nucleic acids from the portion and for transferring the portion from the first container to a second container; a nucleic acid measurement system 14 for measuring the concentration of nucleic acids in the portion; a PCR preparation system 16 for adding polymerase chain reaction (PCR) reaction materials to the portion; a thermocycling system 18 for amplifying a target sequence and extending a primer in the portion; a primer extension preparation system 20 for adding primer extension reaction materials to the portion; a mass spectrometry preparation system 22 for removing a sample of the portion from the second container to a platform for analysis by mass spectrometry; and a mass spectrometry system 24 for analyzing the sample.

The central controller is capable of controlling one or more system modules, collecting and organizing data obtained from one or more of the system modules and an outside system or database, and of sending data to one or more of the system modules and an outside database (e.g., a database accessible by healthcare providers or third parties) or system (e.g., an outside computer through which health care providers or third parties can access the data). The input device 6 associated with the central controller can be a bar code reader. The system can optionally include a detection system 5 for detecting and tracking a sample as it progresses through the system. The system can also include a transport subsystem 25, e.g., a system of one or more robotic arms and/or tracks, for transporting samples between two or more modules within the system.

Central Controller

Typically, the central controller 4 is a computer system. The computer systems that can be used are commonly available personal computers having read-write memory, or industrial counterparts thereof. The central controller is provided with a suitable input device 6 such as a keyboard, touch screen, card reader, bar code scanner, or another computer (e.g., for inputting biological sample processing instructions and patient identification information).

The central controller 4 is run by linking software, which directs the central controller to receive information from, and/or transmit information to, each of the modules in the overall system. For example, the central controller can be configured to exchange information with one or more modules within the clinical assay system, and to relay that information to one or more other modules. Such information may include information about a biological sample, e.g., sample identification, information as to which assay(s) is to be/has been performed on a sample, and the location of a sample within the clinical assay system and within a given batch of samples being processed.

The central controller 4 is also configured to exchange information with outside systems and/or databases 8 (i.e., systems or databases not part of the clinical assay system). This configuration allows the central controller to report, e.g., the results of the clinical assays described herein, along with other data, e.g., billing amounts, patient identification, and other data to health-care providers (e.g., technicians, nurses, physicians) and/or third parties (e.g., insurance providers) at other sites. Reporting can occur automatically. Exemplary of outside systems are systems capable of interfacing directly with the central controller, or with a database accessible by both the outside system and the central controller. For example, Meditech™ provides a laboratory application that allows multisite and/or multifacility specimen tracking, through which the central controller can exchange information with outside systems.

Sample Transfer Module

The sample transfer system 10 can be any system capable of receiving a biological sample, e.g., a blood sample, removing an aliquot of the sample, and placing the aliquot into one or more receptacles. Exemplary systems are pipetting robots, such as the Genesis® Freedom™ Automated Workstation. The system is capable of scanning sample tube barcodes and multiwell (e.g., 96-well) plates, and creating a file that indicates where on the multiwell plate a sample is located following the transfer. The file can include information such as the barcodes of scanned sample tubes, the location of these samples on the multiwell plate, the volume transferred from the sample tube to the plate, and overall identifying information (e.g., a barcode) for of the multiwell plate (called DNA plate).

Nucleic Acid Extraction Module

The nucleic acid extraction system 12 can be any system capable of carrying out techniques, such as those described herein, for purifying nucleic acids (i.e., DNA and/or RNA) from one or more biological samples. An example of such a system is the BioRobot® MDx produced by Qiagen.

Nucleic Acids Measurement Module

The nucleic acids measurement system 14 can be any system capable of measuring the concentration of nucleic acids in a sample. For example, the system can be a commercially available ultraviolet (UV) light spectrophotometer, which is capable of determining the concentration of nucleic acids using optical density measurements. As another example, the system can be capable of measuring the UV-induced fluorescence of dye (e.g., ethidium bromide or Pico Green) intercalated into the nucleic acid, such as a fluorometer. The Genesis® Freedom™ Automated Workstation produced by Tecan can include such a fluorometer. The nucleic acid measurement system can be associated with (e.g., a part of) the sample transfer system, or it can be a stand-alone module.

PCR Preparation Module

The PCR preparation system 16 can be any system capable of adding appropriate materials, e.g., enzymes (e.g., Taq polymerase), nucleic acid primers, individual nucleotides, and reagents, to an aliquot in preparation for amplifying a target sequence in the aliquot. The PCR preparation also prepares appropriate control reaction mixes. Examples of such systems are the Genesis® Automated Workstation and the Tecan TeMO™ multi-pipetting module.

Overall, the PCR preparation system is capable of performing at least two steps. The first is to dispense appropriate assay mixes. Assay mixes can be prepared by an individual, e.g., a technician, or by a robot, according to typical laboratory procedures, and placed into holders. These PCR preparation system dispenses the mixes from the holders to a position on a second multiwell (e.g., 384) plate, according to instructions (e.g., sample identification and assays to be performed) it receives from a plate editor 7 (described in detail below). The second is to add samples to the appropriate assay mix. Using the file received by the PCR preparation system 16 from the sample transfer system 10, the PCR preparation system transfers samples from the first multiwell (e.g., 96 well) plate to the second multiwell (e.g., 384 well) plate. In this way, the PCR preparation system is able to transfer samples from a first plate to a second plate, while keeping track of the location of the samples, and to ensure that the appropriate assays are performed on each sample.

Thermocycling Module

The thermocycling system 18 can be any system capable of performing PCR reactions, e.g., PCR amplification and/or primer extension reactions, and is typically a commercially available thermocycler. Exemplary systems include the GeneAmp PCR System 9700 manufactured by Applied Biosystems, the Perkin Elmer 2000 PCR thermocycler, and the PTC-200 thermocycler manufactured by MJ Research.

Primer Extension Preparation Module

The primer extension preparation system 20 can be any system capable of adding appropriate materials, e.g., Shrimp Alkaline Phosphatase (SAP; to dephosphorylate unincorporated dNTPs), extension primers (e.g., the extension primers described herein), and appropriate mixtures of dNTPs and ddNTPs, to an aliquot in preparation for performing primer extension reactions. An exemplary system is the Multimek™ manufactured by Beckman-Coulter

Mass Spectrometry Preparation Module

The mass spectrometry preparation system 22 can be any system capable of removing a sample of an aliquot and placing the sample on a support, e.g., a chip, for analysis by mass spectroscopy. The support can be composed of any material known to those skilled in the art to be usable in mass spectrometry, e.g., silicon, plastic, glass, and/or ceramic. A wide variety of chips are commercially available. Exemplary of chips is the Sequenom® SpectroCHIP™, which is supplied in 384 well format and are pre-spotted with a specially formulated matrix assisted laser desorption ionization (MALDI) matrix. The matrix can be of any composition known in the art of mass spectrometry, e.g., α-cyano-4-hydroxy cinnamic acid (CHCA), 2,4,6-trihydroxy acetophenone (THAP), or 3-dydroxypicolinic acid (3-HPA) in ammonium citrate, the choice of which will depend, e.g., on the mass spectrometry system used and the assay to be performed. Exemplary of the mass spectrometry preparation systems is the Sequenom® SpectroPOINT™, a nanoliter sample dispensing instrument.

Mass Spectrometry Module

The mass spectrometry system 24 can be any commercially available mass spectrometer. The clinical assay system of the present invention can be configured to utilize mass spectrometer formats including matrix assisted laser desorption ionization (MALDI), electrospray (ES), ion cyclotron resonance (ICR) and Fourier Transform. In one embodiment, maMALDI is utilized in the clinical assay system of the present invention. An exemplary mass spectrometry system is the Sequenom® Autoflex™ Mass Spectrometer.

With MALDI mass spectrometry, various mass analyzers can be used, e.g., magnetic sector/magnetic deflection instruments in single or triple quadrupole mode (MS/MS), Fourier transform and time-of-flight (TOF) configurations as is known in the art of mass spectrometry. For the desorption/ionization process, numerous matrix/laser combinations can be used. Ion-trap and reflectron configurations can also be employed. In one embodiment of the present invention, MALDI-TOF is employed to analyze the biological samples.

Transport Subsystem

Optionally, the clinical assay system includes a transport system 25. The transport system can be capable of (i) transporting containers, e.g., containing biological samples, from a source (e.g., a separate site in which biological samples are obtained from a patient) to the clinical assay system; (ii) transporting containers between at least two modules within the clinical assay system; and/or (iii) transporting containers away from the clinical assay system to a predefined destination after completion of the assay. The transport system is capable of communicating with the central controller so the central controller can direct the transport system and/or receive information as to the location of sample within the clinical assay system. The transport system can comprise one or more robotic arms or tracks, or a combination of robotic arms and tracks.

Detection System

Optionally, the clinical assay system includes a detection system 5 for detecting the presence of a biological sample and monitoring the progress of the sample through the system. The detection system is capable of receiving information from and transmitting information to the central controller. The detection system can include a network of sensors, e.g., barcode readers, reed switches, weight systems (where the detector detects the presence of a sample by its weight); or optical interrupters, or combinations thereof, arranged throughout the clinical assay system, each of which are capable of transmitting information, directly or indirectly, to the central controller.

Software

The clinical assay system includes novel software for adapting one or more modules to be used in the system. For example, the central controller includes a novel software program to provide an interface between itself and an outside system or database (e.g., Meditech). In addition to causing the central controller to receive data from an outside source, the software causes the central controller to send information (e.g., automatically) about the clinical assays (e.g., the results and/or billing information) to at least one outside system (e.g., a computer not associated with the clinical assay system) or at least one outside database (e.g., a Meditech database). This configuration allows the clinical assay system to directly report results and billing information to at least one healthcare provider, at least one third party payor (e.g., an insurance company), or to both.

Optionally, the software can be written such that the central controller performs a final check of assay results before sending to the outside system or database, halting transmission of the data and/or alerting a technician of potential problems with the results. For example, where two samples from the same patient are submitted for duplicate analyses by the clinical assay system, the interface program can include a checking scheme to ensure that the results of the duplicate analyses agree with each other. If the duplicates do not agree (e.g., where both a positive and a negative result are reported to the central controller by the clinical assay system), the interface program can halt transmission of the results so that the mass spectroscopy data can be reanalyzed or to allow the assays to be performed again.

The central controller also includes a software program for linking at least one other module of the system to the central controller (“linking software”). The module(s) also include linking software allowing the module(s) to communicate with the central controller. For example, the linking software can allow the central controller to control the module (e.g., to instruct the module as to when and whether to execute a function), and to provide to the module(s) information about the biological sample (e.g., the tests to be performed on the sample). The linking software also allows the central controller to receive information from the module(s), e.g., assay results, information about the location of the sample, and the like.

Also included within the clinical assay system is plate editor software 7. The plate editor software can be loaded on the central controller and/or on a separate computer, e.g., a second computer system. The plate editor software can receive information from an outside system or database, such as patient information, tests to be performed, billing information, etc., and create a file that maps on a hypothetical 384-well plate where each assay for each sample will be located, and links this location to all data and information associated with each assay (one sample can have several assays, e.g., 1, 2, 3, or 4 assays). In this way, the plate editor software “maps out,” in advance of processing a batch of samples through the clinical assay system, an arrangement of assays on a 384-well plate. This file can be used by other modules in the system, e.g., the sample PCR preparation system and the mass spectrometry system, to track the samples and their associated assay results as they move through the system.

Also included is a relational database 9, e.g., Oracle software. Like the plate editor software, the relational database can be loaded on the central controller and/or a separate controller, e.g., a second computer system. The relational database stores information from the plate editor and from an outside database or system (e.g., Meditech), and can be accessed by the outside system or database.

The sample transfer system 10 can include software causing it to receive at least one biological sample (e.g., a batch of samples), to obtain information about each sample (e.g., from a bar code associated with the sample), and to place an aliquot of the sample into a multiwell plate while keeping track of the location of the aliquot within the multiwell (e.g., a 96 well) plate. The software can instruct the sample transfer system to compile the information (e.g., identity of the sample and the location of the sample in the multiwell plate) into a file, which can then be transmitted to the central controller and/or other modules, e.g., the PCR preparation system.

An example of software that can be used, for example, with sample transfer system 10 is attached hereto as Appendix 1 and is described in detail below.

OutFileGenerator.exe

Laboratory software, e.g., Gemini™ (Tecan) software, allows users to control robotic and liquid handling functions and to write specific application scripts based on the user\'s needs. OutFileGenerator.exe is part of the Gemini program that performs specimen transfer from original bar-coded tubes into a 96-well destination plate, prior to extraction. First, all racks, test tubes, and destination plates are scanned by the barcode scanner. The positions of all racks, tubes, and destination plates, are loaded to the file C:\Program Files\Gemini\Output\” created by Gemini the function. OutFileGenerator.exe creates another file, called “outputdestID.csv” (destID=barcode of the destination plate), by rewriting the original “Output” file such that it contains the following information in a consistent order: DNA ID, DestWellID (well number in the destination plate), Dest ID (ID of destination plate (as determined by the barcode of the plate), SourceWell ID (position of the tube in the rack), and Source ID (barcode of the rack).

Because samples are often transferred from one plate to another during the extraction process, both plates can be assigned the same barcode number. Alternatively, a script similar to “output file generator” can be used to rename the file and destination plate ID after extraction is complete.

The PCR preparation system can include software causing it to obtain information (e.g., sample identification and assays to be performed on each sample) about each sample from the sample transfer system and the plate editor, and causing it to add specific PCR materials (e.g., specific primers, nucleotides, etc.) to each sample. In this way, the PCR preparation system is instructed as to which test(s) is to be performed on a given sample, and the PCR preparation system adds the materials appropriate for performing that test(s).

In particular and as discussed above, the software can cause the PCR preparation system to (a) dispense appropriate assay mixes; and (b) to add samples to the appropriate assay mix. Examples of programs instructing functions (a) and (b) are attached hereto as Appendix 2 and 3, respectively, and are described in further detail below.

(a) Assay Transfer.gem

Assay Transfer.gem is an exemplary Gemini program (Appendix 2) for dispensing an aliquot 3 μl, e.g., of assay mixes to PCR plates, e.g., 384-well plates, (i.e., performing function (a) as discussed above). It uses a file called “input file,” which is exported from Plate Editor MassARRAY (Sequenom). This file contains all information about the PCR plate, e.g., the location on a plate a particular assay will be run and into which a particular DNA sample should be placed, as well as the barcode of the plate. The following fields are exported from the Plate Editor and are contained in “input file”: Plate ID—PCR plate barcode number; Group ID—name of the MassARRAY file; Assay ID—name of the assay; Sample ID—specimen\'s barcode; and Well Position—position in the plate. Hence, each position in the plate(s) is described by the fields described above, i.e., plate ID, Assay ID, and Sample ID. This file is used in both Assay Transfer.gem and DNA Transfer.gem, which is described in further detail below.

In this Gemini program are imbedded three executable scripts written in Visual Basic (VB): PCRMix Transfer.exe, Move File Assays.exe, and MoveFileProcessed.exe. Generally, in this program, Module 1 changes the name of a letter/number well (e.g., A1, A2) description, into a well number for a 96 well plate; Module 2 performs the same function as Module 1, but for a 384 well plate; Module 3 includes comments for module 4 execution; and Module 4 generates a worklist for making the transfer of assay mixes into a 384 well plate.

Specifically, the events as dictated by the program are as follows: 1) the barcode of the PCR plate is read by barcode reader (Gemini script); 2) the major part of the program is run by PCRMix Transfer.exe, VB script: a) the input file is opened and the column “Well Position” containing alphanumeric characters is divided into two columns: one contains alpha-characters and the second contains numerical characters; b) the file is sorted by column containing numerical characters, meaning that assay mixes will be dispensed later by columns. Hence, all 8 tips will be used at the same time in most cases, speeding up the process of dispensing PCR mixes; c) module 2 PCR Mix takes a combination letter/number well description and converts it to a well number for a plate (e.g., A1=1); d) the Gemini program loads “worklist,” and Module 3 contains directions to read the .ini file which describes the location and names of: Input File=C:Gemini\Data\Assays\Input File; Worklist file=C:\Gemini\Data\Assays\assays.gwl; Source Type=Trough 1 column; Dest Plate=384 well Marsh; Volume=3 (volume of assay mix dispensed); and WashWorklist; and e) module 4: (1) opens the sorted Input file and parses it to determine the well into which a particular PCR mix goes into; (2) gives information about where to find the PCR Mix—the ID of the PCR Mix (assay) is written in Gemini file by naming the Trough with the PCR Mix ID; (3) directs when, where and how washes are performed. Each wash is carried out as follows: (i) aspiration of 290-400 μl of bleach; (ii) tips are immersed in the bleach for 10 seconds; (iii) bleach is dispensed into wash station; followed by (iv) three washes with water, for example: 10 ml, 5 ml, 5 ml each. Bleach washes of the tips are performed if the Mix ID is different. A full wash (both bleach and water) is always performed at the end of worklist. 3) the data from the run is exported into an output file by the “Export Data” command in the Gemini program; 4) the worklist is copied and saved under a barcode.txt file name (i.e., barcode of 384-well PCR plate) by Move File Assays.exe. Hence, the worklist file is emptied and ready for the next run; and 5) the above file is moved from the original directory into an Output Processed Directory by MoveFileProcessed.exe script.

In short, the following commands are contained in the Gemini program: number of plates to be run (in Gemini); reading of barcodes (instructions in Gemini); Execute: C:\programFiles\PCRMixTransfer\PCRMix Transfer.exe; Load Worklist; C;Gemini\Data\Assays\assays.gwl; Execute loaded worklist; Export Data; Execute: C:\ProgramFiles\\Project\Move File Assays.exe; and Execute: C:\ProgramFiles\MoveFileProcessed\MoveFileProcessed.exe.

(b) DNA Transfer.gem

The DNA Transfer.gem program (Appendix 3) is an exemplary Gemini program for obtaining an aliquot, e.g., 2 μl, of DNA aspirated from DNA plate, e.g., a 96-well plate, and dispensing it to PCR plate, e.g., a 384 well plate, which contains a particular PCR mix. There are four executable scripts written in VB in this program: DNATransfer.exe; MoveFile.exe; FinalOutputConverter.exe; and CompareFiles.exe.

Generally, the program uses two files. The first, “InputFile,” is exported from the Plate Editor of MassARRAY software saved in csv format (which is the same file used in AssayTranfer.gem for dispensing the PCR mixes). This file dictates where the DNA will be dispensed in the PCR plate (e.g., 384-well plate) by giving for each specimen ID an exact destination, i.e., a specific plate and well. The second, “Output\'barcode#.csv,” (made on Freedom™ (Tecan) by OutFileGenerator.exe) specifies the location of DNA samples in a particular 96-well DNA plate. Based on these two files, a worklist is prepared, which dictates where the DNA samples are dispensed to the PCR plate (destination plate).

In short, the following commands are contained in this Gemini program: How many DNA plates will be run (in Gemini)?; How many PCR plates will be run (in Gemini)?; Reading the plates barcodes (instructions in Gemini); Execute: C:\programFiles\DNATransfer\DNATransfer.exe; Loading worklist C:\Gemini\Data\DNAtransfer\DNA list gwl; Execute loaded worklist; Export Data; Execute: C:\programFiles\MoveExistFiles\MoveFile.exe; Execute: C:\programFiles\FinalOutputConverter\FinalOutputConverter.exe; and Execute: C:\programFiles\CompareFiles\CompareFiles.exe

The details of the program are provided below. 1) At the start of the program, there are instructions written in Gemini which ask: how many DNA plates will be run? How many PCR plates will be run? Instructions for reading the barcodes of each DNA plate and PCR plate are provided. 2) The major part of the DNA Transfer.gem is run by DNA Transfer.exe in VB script: Module 1: instructs that the ‘input file’ is opened and the column “Well Position” containing alphanumeric characters is divided into two columns: one contain alpha-characters and second containing numerical characters; the file is sorted by column containing numerical characters first and then by column with alpha-characters. Module 2: instructs conversion of combination letter/number well descriptions to a well number for a 384 well plate. (for example A1=1). Module 3: contains instructions to read the .ini file which describes the location and names of: DataFile-=Input File; Worklist; Source Type=96 well plate Sarstedt; Destination Plate=384-well Marsh; and Volume=2 (volume of dispensed DNA). Module 4: (a) contains a loop that takes each DNA ID from the ‘inputfile’ and goes through all files in the Output directory (containing Output\'barcode#.csv” files) looking for the match of the ID to determine which well of the source plate from which a sample should be taken; and (b) creates a workfile containing all information needed for each DNA transfer, such as DNA ID, source well number, source plate type, source plate ID (that is a barcode of the 96-well DNA plate), volume to transfer, destination plate type, destination plate ID (barcode of 384-well PCR plate), destination well and tip number to be used; (c) CreatesTextFile(“C:\Gemini\Logfiles\DNAIdLog.txt”); (d) instructs when, where and how the washes are performed. Each wash is carried out as follows: (i) aspiration of 290-400 μl of bleach; (ii) tips are immersed in the bleach for 10 seconds; (iii) bleach is dispensed into wash station; followed by (iv) three washes with water, for example: 10 ml, 5 ml, 5 ml each. Bleach washes of the tips are performed if the Mix ID is different. A full wash (both bleach and water) is always performed at the end of worklist; and e) instructs termination of the run if it cannot file DNA in the outputbarcode file .csv plate, giving the message:“DNA Ids missing! See DNAIdLog, fix files, and rerun”; (f) when all DNAs are found, the worklist is made and the files Output\'barcode#.csv are moved from :\Gemini\Output directory to C:\Gemini\OutputProcessed. 3) Worklist is loaded to Gemini and executed by Gemini command. 4) Worklist is copied and saved under ‘outbarcode.txt’ file name (barcode of 384-well PCR plate) by MoveFile.exe. Hence, the worklist file is emptied (cleaned out) and ready for the next run. 5) FinalOutputConverter.exe module 1 converts the original output file and puts it in a readable format containing: “DNA ID,” “Destination Well ID,” “Destination plate ID,” “Source Well ID,” and “Source Plate Id.” Module 2 converts well number from integer (1) back to alphanumeric well number (A1). Module 3 scans the directory and looks for files and converts them by adding the date to the files. 6) In addition to checking DNA IDs between two files: ‘InputFile’ and ‘BarcodeOutput file(s)’ before the transfer starts (DNATransfer.exe module 4) CompareFiles.exe compares the “InputFile” with LogFile for correctness in transfer from source 96-well plate(s) to destination 384-well plate(s). It gives an error message if DNA is found to be missing.

The primer extension preparation system can include similar software, i.e., software that causes it to receive information about each sample and the assays to be performed, so that the primer extension preparation system adds the specific primer extension reaction materials (e.g., specific detection extension primers, termination mixes, etc.) appropriate for performing that test(s) on the sample.

The methods and systems described herein can use a communications network to transmit information from the system (e.g., from the central controller) to healthcare providers and/or insurance companies. These communications networks can use either wired or wireless interfaces. For example, a communications network can be the internet, or a wire or optical cable.

The new methods can be carried out using various means of data storage. For example, the information or data relating to each sample can be stored on a computer-readable medium or in a computer memory. The information can be transferred physically on diskettes or electronically, e.g., on a dedicated intranet, or on the Internet. The data can be encrypted using standard encryption software from such companies as RSA Security (Bedford, Mass.) and Baltimore®. The data can be stored in various formats, e.g., spreadsheets or databases.

The invention can be implemented in hardware or software, or a combination of both. The invention can be implemented in computer programs using standard programming techniques following the method stern and figures disclosed herein. The programs (or scripts) should be designed to execute on the various modules or in the central controller. The output information is transmitted to one or more output devices such as a printer, or a CRT or other monitor, or a web page on a computer monitor with access to a website.

Each program used in the new methods can be implemented in a procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In any case, the language can be a compiled or interpreted language.

Each computer program can be stored on a storage medium or device (e.g., ROM or magnetic diskette) readable by a general or special purpose programmable computer, for configuring and operating the central controller when the storage media or device is read by the controller (or a given module) to perform the steps or procedures described herein. The system can also be considered to be implemented as a computer-readable medium, configured or encoded with a computer program, where the storage medium so configured causes a computer to operate in a specific and predefined manner to perform the functions described herein.

Although any communications network can be used, the Internet provides a useful choice to transmit data. In this method, files of data are transmitted from the system to a user in encrypted form, with each party privy to the decryption technique necessary to process the particular data, ending with the completely processed data being sent to the health care provider over the Internet in a similarly encrypted manner. In this method, the entire process can be performed in minutes once the biological sample has been obtained and processed.

The data is typically provided in digital form that can be transmitted and read electronically, e.g., via the Internet, on diskette, or any other mode of electronic or non-electronic communication.

As used herein, “sequence information” refers to any nucleotide and/or amino acid sequence information, including but not limited to full-length nucleotide and/or amino acid sequences, partial nucleotide and/or amino acid sequences, or mutated sequences. Moreover, information “related to” the sequence information includes detection of the presence or absence of a sequence (e.g., detection of a mutation or deletion), determination of the concentration of a sequence in the sample, and the like. These sequences can be read by electronic apparatus and can be stored on any suitable medium for storing, holding, or containing data or information that can be read and accessed by an electronic apparatus. Such media can include, but are not limited to: magnetic storage media, such as floppy discs, hard disc storage medium, and magnetic tape; optical storage media such as compact disc; electronic storage media such as RAM, ROM, EPROM, EEPROM and the like; general hard disks and hybrids of these categories such as magnetic/optical storage media. The medium is adapted or configured for having recorded thereon sequence information.

As used herein, the term “electronic apparatus” is intended to include any suitable computing or processing apparatus or other device configured or adapted for storing data or information. Examples of electronic apparatus suitable for use with the present invention include stand-alone computing apparatus; communications networks, including local area networks (LAN), wide area networks (WAN), Internet, Intranet, and Extranet; and local and distributed processing systems.

As used herein, “stored” refers to a process for encoding information on the electronic apparatus readable medium. Those skilled in the art can readily adopt any of the presently known methods for recording information on known media to generate manufactures comprising the sequence information.

A variety of software programs and formats can be used to store the sequence information on the electronic apparatus readable medium. Any number of data processor structuring formats (e.g., text file or database) can be employed to obtain or create a medium having recorded thereon the sequence information.

By providing sequence information in computer-readable form, one can routinely access the sequence information for a variety of purposes. For example, one skilled in the art can use the sequence information in readable form to compare a specific sequence with the sequence information stored within a database. Search means are used to identify fragments or regions of the sequences that match a particular sequence.

The present invention therefore provides a medium for holding instructions for performing a method for determining whether an individual has a specific disease or disorder or a pre-disposition, for a specific disease or disorder based on genetic information.

The new methods make use of the new clinical assay systems described herein. One method 26 of using an exemplary configuration of the clinical assay system is described below and illustrated in FIG. 2.

Biological samples to be processed (e.g., blood samples) typically arrive at the clinical assay system in multiple containers such as test tubes. Information about the samples (e.g., patient identification, tests to be performed, expected turn-around time) can accompany the sample and/or can be encoded within a barcode associated with the sample. Referring to FIG. 2, the information is first entered into the central controller (step 28) and/or the plate editor, e.g., using a keyboard or bar code scanner, and optionally coordinated (e.g., matched) with information about the sample received by the central controller from an outside system or database (step 30) (e.g., via a Meditech interface). Information obtained by the central controller can be transmitted to one or more modules of the clinical assay system immediately and/or at appropriate intervals during operation of the system.

The biological samples are deposited in holders in the sample transfer system. Aliquots of the biological samples are removed from the biological sample containers and deposited into multiwell plates by the sample transfer system (step 32). The sample transfer system can include a subsystem, e.g., a barcode scanner and appropriate software, capable of tracking where each aliquot of a biological sample is deposited within the multiwell plate. The information generated via the subsystem can be transmitted to the subsequent modules in the system and/or to the central controller.

The plate containing the aliquots is then transferred to the nucleic acid extraction system for DNA or total nucleic acids extraction (step 34). Following execution of the extraction process, the aliquots are transferred by the nucleic acid extraction system to a different multiwell plate.

The plate containing extracted nucleic acid samples is then transferred to the nucleic acid measurement system wherein the concentration of extracted nucleic acids in each aliquot is measured (step 36). The nucleic acid measurement system can include a subsystem, e.g., appropriate software, for assigning the data generated during the measurement process to each individual aliquot and transmitting this data to the central controller.

The plate is then transferred to the PCR preparation system. The PCR preparation system performs at least related two steps: (1) dispensing appropriate assay mixes, which include all components required for carrying out PCR reactions (e.g., buffers, dNTPs, primers, and polymerase enzyme(s)) (step 37); and (2) dispensing nucleic acid samples, e.g., control and patient DNA samples (step 38). The PCR preparation system can also include a subsystem, e.g., appropriate software, which allows the PCR preparation system to receive from the central controller information specifying which assay(s) is to be performed on a given aliquot, to locate the aliquot on the plate, and to dispense appropriate primers and nucleic acid samples based on those specifications into the aliquot.

The plate is then transferred to the thermocycling system for amplification of the target nucleic acid sequence (step 40). The PCR reactions can be performed using any appropriate thermocycling protocol, e.g., a protocol as described in the Examples section of the present application.

Following execution of the PCR reaction, the plate is transferred from the thermocycling system to the primer extension preparation system. The primer extension preparation system adds a dephosphorylating enzyme, e.g., Shrimp Alkaline Phosphatase (SAP), to each aliquot to dephosphorylate unincorporated dNTPs leftover from the PCR reaction (step 41). The plate is then optionally incubated. An extension mix, which includes the extension primer, appropriate enzymes, and a mixture of dNTPs and ddNTPs, is added to each aliquot by the primer extension preparation system (step 42). The primer extension preparation system can also include a subsystem, e.g., appropriate software, which allows the primer extension preparation system to receive from the plate editor information specifying which assay(s) is to be performed on a given aliquot, to locate the aliquot on the plate, and to dispense into each aliquot appropriate extension primers and mixtures of dNTPs and ddNTPs based to those specifications.

The plates are then transferred back to the thermocycling system, or to a second thermocycling system (e.g., a second thermocycling system contained within the primer extension preparation system), to allow the primer extension reaction to occur (step 44). After the primer extension reaction is complete, the plates are optionally transferred back to the primer extension preparation system, where resin is added by the system to the plates to remove salts, which could potentially interfere with MALDI-TOF analysis.

The plates are then transferred to the mass spectrometry preparation system. The system transfers a sample (e.g., nanoliter volume samples) of each aliquot on the plate to a chip (e.g., a silicon chip) for MAI DI-TOF analysis (step 46).

Chips containing the samples are transferred from the mass spectrometry preparation system to the mass spectrometry system. The mass spectrometry system analyzes the samples using MALDI-TOF mass spectrometry (step 48). Specifically, the mass spectrometry system analyzes extended detection extension primers on the basis of molecular weight. Software associated with the mass spectrometry system receives the raw mass spectrometry data, performs digital signal processing (e.g., de-noise, baseline determination, and data compression), analyzes the data, and calls the geneotype according to the resulting data (e.g., mass data). The software associated with the mass spectrometry system optionally receives information from the central controller and matches the data with information about the sample (e.g., patient identification and the assay performed). The data is exported from the mass spectrometry system to the relational database and/or central controller (step 49).

The finalized data, e.g., patient name, assays performed, and genotype, are exported from the relational database and/or the central controller to an outside system or database (e.g., a Meditech database) (step 50), e.g., via an interface program, e.g., automatically. The outside system or database is accessible by healthcare providers and/or third party payors. Optionally, the information exported from the central controller to the outside system or database can include billing information, e.g., billing codes for the test or tests performed, allowing direct billing of a third party payor for services rendered.

Optionally, the central controller can be programmed to include with the test results diagnosis information. Such information can be used to facilitate, or give a definitive, diagnosis. For example, with regard to infectious diseases, the diagnostic information can include an indication that a patient has been infected with a particular pathogen, the severity of the infection, the genotype of the organism (e.g., to facilitate the tailoring of a treatment, e.g., to treat a drug resistant organism with a drug to which it is sensitive), and a recommended regimen of treatment. As another example, with respect to genetic mutations that predispose an individual to genetic disease, the information can indicate whether the patient is hetero- or homozygous for the mutation, the likelihood that the patient will develop a disease or condition because of the mutation, and recommend a course of action such as a regimen of treatment or prevention. Such information can be associated with the patient data as necessary and exported from the central controller to the outside database or system.

In addition to the new system, the present invention provides novel diagnostic assays. The assays employ novel primer sequences and mass spectrometry (e.g., MALDI) to detect the presence of target nucleic acid sequences and/or sequence variations (e.g., insertions, mutations and/or polymorphisms) in biological samples. The assays can be categorized into two groups: genetic tests (e.g., to detect mutations) and infectious disease/pathogen testing (e.g., to detect the presence and/or amount of foreign, e.g., viral and/or bacterial, nucleic acids, and/or to genotype the pathogen). A general description of the assays is provided below, and several exemplary assays are described in the Examples.

Design of Primers and Specific Considerations

In one embodiment, the novel genetic assays of the present invention require primers for PCR amplification of a target sequence and detection extension primers for carrying out primer extension reactions.

A target sequence can be, e.g., a sequence that is part of a gene, or a mutation (e.g., insertions, deletions, transitions, or transversions), which is known, or suspected, to be associated with (e.g., cause, increase, or decrease the risk of) a genetic disease or disorder. A target sequence can also be a sequence that is part of a pathogen\'s (e.g., a virus, bacterium, or fungus) genome, which optionally is known or suspected to include variations (e.g., insertions, deletions, transitions, transversions, etc.) conferring special characteristics, e.g., possession of virulence factors and/or drug resistance, and/or which serve to differentiate among strains of the organism.

Generally, to generate amplification primers, a 100 bp stretch of nucleotides is first selected from either or both sides of a target sequence. A set of primers is then created manually and/or by using commercially available primer-generating software. An example of such a program is the Sequenom® Spectro Designer™ program. This results in a first generation of amplification primers and appropriate detection extension primers.

The first generation of extension and/or amplification primers is analyzed using a second program, such as OLIGO® Primer Analysis Software (Macintosh, Molecular Biology Insights, Inc.), which evaluates each primer with regard to melting temperature of the primer (Tm), potential hairpins in each primer (judged by free energy (AG), number of nucleotides in the loop, and Tm of the hairpin), and potential for primer dimerization. This analysis results in a second generation of primers.

The second generation of amplification and/or extension primers is then compared to other known sequences, e.g., using a BLAST program (see, e.g., the National Institutes of Health\'s National Center for Biotechnology Information (NCBI) website on the World Wide Web at address ncbi.nlm.nih.gov). Primers that match with a sequence other than the target sequence are disregarded. Primers that match with only the target sequence are considered a third generation of amplification primers and are retained for further analysis.

All possible combinations of the third generation of amplification primers and the detection extension primers are run through the diagnostic genetic assay with positive and negative controls to identify sets of primers that are accurate in 100% of genotype calls. Amplification primers so identified are considered a fourth generation of amplification primers, and are suitable for use in the assays of the present invention.

The procedures discussed above can be modified for designing primers for a target gene when a homologous pseudogene(s) is known to be present, e.g., the glucocerebrosidase (GC) gene, which is involved in Gaucher Disease. Many commercially available software packages are not able to design specific primers when a homologous sequence to the target gene is present in the genome. Many design primers that amplify short stretches of DNA sequence (60 bp to 150 bp) because PCR is more efficient when short fragments of DNA are amplified. Where pseudogenes are present, however, the amplified fragments of DNA often must be as large as 1000 bp or more. In such cases, at least one of the amplification primer sequences directed against the functional gene must not be present in the pseudogene sequence. For example, based on a comparison of the target gene and pseudogene sequences, a primer can be designed, manually or using software, e.g., software other than SpectroDESIGNER™, that will prime the target gene, but not the pseudogene (homologous) sequence. The extension primer can then be designed using software, e.g., SpectroDESIGNER™. Each amplification and extend primer can then be analyzed using a program like BLAST for specificity (i.e. absence of repetitive or homologous sequences) of the sequence. At least one of the amplification primers should be specific.

In certain embodiments of the invention, duplicative confirming assays are used. In such cases, an assay is designed around a target using both the sense and antisense strand sequences, designing both forward and reverse detection extension primers. The results from both assays can be compared. Duplicative confirming assays can be beneficial, for example, if the region surrounding the target includes polymorphisms that prevent the PCR amplification and/or extension primers from working, which would cause erroneous results. They can also reduce the occurrence of mistaken calls, e.g., the calling of a heterozygote as a homozygote in an instance when one primer on one allele does not work because of a polymorphic sequence. Generally, when designing these types of confirming assays, two sets of amplification primers are prepared, each extend primer having its own pair of amplification primers. The second pair of amplification primers are designed either manually or using a program, e.g., a program other than SpectroDESIGNER™.

In certain other embodiments, primers for targets can be designed using more than one type of software, e.g., using SpectroDESIGNER with the input of another sequence aligning software, for additional security when manipulating sequences. For example, in one assay design protocol, the sequence having the deletion/insertion is duplicated. One of the sequences is used to design a forward extension primer, while the other sequence is used to design a reverse extension primer. SpectroDESIGNER™ is used to design extension primers in the forward or reverse direction. To force SpectroDESIGNER™ to design extend primers in the forward or reverse direction, the letter “N” can be introduced into the sequence at a position 3′ to the deletion/insertion site when designing the forward extend primer, or 5′ to the deletion/insertion site when designing a reverse extension primer.

The targets for SpectroDESIGNER™ when designing primers for a deletion/insertion site is the first base in the deletion or insertion and the first base after the deletion or insertion. Often, these two nucleotide targets differ for the forward and reverse extension primers. The sequence following the target nucleotides for a forward extend primer can omit the first nucleotide after the deletion/insertion; and, similarly for the reverse extend primer, the nucleotide prior to the deletion/insertion can be omitted. For the purpose of designing the assay with a forward extension primer, in certain instances the sequence following a target should be the sequence that actually follows the deletion/insertion site in genomic DNA. In other cases, the target should be followed by the deleted/inserted sequence. Similar considerations are applicable to designing reverse primers. The choices of how to design the primers in view of these considerations can be dictated to SpectroDESIGNER™ by a second type of software, e.g., software other than SpectroDESIGNER™. The validity of the extension primer designed by SpectroDESIGNER™ is checked by aligning the extended primer sequences (Ext1 and Ex2) with the template sequence, with and without the insertion/deletion in order to check the validity of assay design.

Novel Primers

A number of novel primers were isolated for use in the assays of the present invention. Accordingly, the present invention includes the following nucleic acid sequences, in which the MTHFR primers are used to detect mutations in the 5,10-Methylenetetrahydrofolate Reductase gene, the FaII primers are used to detect mutations in the Coagulation Factor II (FII) gene, the FaV primers are used to detect mutations in the Coagulation Factor V (FaV) gene, and the HFE and FM primers are used to detect mutations in the HFE gene. All others are used to detect the presence and amount of cytomegalovirus (CMV) in a biological sample.

(SEQ ID NO: 1) MTHFR-F1 5′-ACGTTGGATGATGCCTTCACAAAGCGGAAG-3′ (SEQ ID NO: 2) MTHFR-R2 5′-ACGTTGGATGCTTGAAGGAGAAGGTGTCTG-3′ (SEQ ID NO: 3)

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