DNA technology for the detection of common genetic variants that predispose to thrombophilia

With the identification of common single locus point mutations as risk fact ors for thrombophilia, many DNA testing methodologies have been described f or detecting these variations. Traditionally, functional or immunological t esting methods have been used to investigate quantitative anticoagulant def iciencies. However, with the emergence of the genetic variations, factor V Leiden, prothrombin 20210 and, to a lesser extent, the methylene tetrahydro folate reductase (MTHFR677) and factor V HR2 haplotype, traditional testing methodologies have proved to be less useful and instead DNA technology is more commonly employed in diagnostics. This review considers many of the DN A techniques that have proved to be useful in the detection of common genet ic variants that predispose to thrombophilia. Techniques involving gel anal ysis are used to detect the presence or absence of restriction sites, elect rophoretic mobility shifts, as in single strand conformation polymorphism o r denaturing gradient gel electrophoresis, and product formation in allele- specific amplification. Such techniques may be sensitive, but are unwieldin g and often need to be validated objectively. In order to overcome some of the limitations of gel analysis, especially when dealing with larger sample numbers, many alternative detection formats, such as closed tube systems, microplates and microarrays (minisequencing, real-time polymerase chain rea ction, and oligonucleotide ligation assays) have been developed. In additio n, many of the emerging technologies take advantage of colourimetric or flu orescence detection (including energy transfer) that allows qualitative and quantitative interpretation of results. With the large variety of DNA tech nologies available, the choice of methodology will depend on several factor s including cost and the need for speed, simplicity and robustness. Blood C oagul Fibrinolysis 11:683-700 (C) 2000 Lippincott Williams & Wilkins.