Duplex PCR-RFLP for simultaneous detection of factor V Leiden and prothrombin G20210A

Factor V Leiden and prothrombin 20210G>A [corrected] mutation and paediatric ischaemic stroke: a case-control study and two meta-analyses

AIM

To determine whether factor V Leiden (FVL) and prothrombin (PT) 20210G>A mutation are associated with paediatric ischaemic stroke.

METHODS

The study consisted of two parts. Case-control study included neuroradiologically confirmed paediatric ischaemic stroke patients from two tertiary children's hospitals in Estonia. For control group, DNA was obtained from 400 anonymous screening test cards of newborns born consecutively in all delivery departments of Estonia in January 2005. Meta-analyses was performed to assess the association between paediatric sinovenous thrombosis and FVL and PT 20210G>A.

RESULTS

A total of 75 children (45 boys, 30 girls) were included into the case-control study: 19 with childhood arterial ischaemic stroke, 49 with perinatal arterial ischaemic stroke and seven with cerebral venous thrombosis. Both FVL and PT 20210G>A occurred significantly more frequently among patients with sinovenous thrombosis compared with controls (OR = 12.9; 95% CI: 2.3-73.0 and OR = 11.9; 95% CI: 2.1-67.2, respectively). The difference was not significant between childhood/perinatal arterial ischaemic stroke and controls. Meta-analyses (including our study) revealed that both FVL and PT 20210G>A are associated with paediatric sinovenous thrombosis (OR = 3.1; 95% CI: 1.8-5.5 and OR = 3.1; 95% CI: 1.4-6.8, respectively).

CONCLUSION

FVL and PT 20210G>A are associated with paediatric sinovenous thrombosis.

Analytic validity of genetic tests to identify factor V Leiden and prothrombin G20210A

The objective of this study is to systematically review methods for detecting Factor V Leiden or prothrombin G20210A. English-language literature from MEDLINE, EMBASE, The Cochrane Library, the Cumulative Index to Nursing and Allied Health Literature, PsycInfo(c), 2000-December 2008. Studies assessed methods for detection of these mutations in at least 10 human blood samples and reported concordance, discordance, or reproducibility. Two investigators abstracted data on the sample selection criteria, test operators, DNA extraction, experimental test, reference standard, commercial instruments, concordance rates, explanation of any discordance, and whether discordance resolved after repetition. We assessed strength of the evidence using the GRADE criteria. We reviewed 7,777 titles and included 66 articles. The majority of the reviewed studies used PCR-RFLP or AS-PCR as the reference standard. The studies demonstrated that commercially available and precommercial tests have high analytic validity with all having greater than 99% concordance with the reference standard. With a few exceptions, discordance resolved with repetition of the test, suggesting operator or administrative errors were responsible for the discordant results. In the quality assurance studies, greater than 98% of laboratories demonstrated high, even perfect, accuracy when asked to diagnose a sample with a known mutation. The majority of errors came from a limited number of laboratories. Although not all methods may be accurate, there is high-grade evidence that genetic tests for the detection of FVL and prothrombin G20210A have excellent analytic validity. There is high-grade evidence that most, but not all, clinical laboratories test for FVL and prothrombin G20210A accurately.

Multiplex PCR-RFLP assay for detection of factor V Leiden and prothrombin G20210A

Factor V Leiden and prothrombin G20210A are clinically relevant genetic risk factors for venous thrombosis. Molecular diagnostic testing for factor V Leiden and prothrombin G20210A is widespread, and laboratories use a variety of technical approaches. Here we introduce a multiplex polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based on single (Mn/l) restriction endonuclease digestion. The assay was shown to simultaneously and accurately detect factor V Leiden and prothrombin G20210A mutations.