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factor V Leiden mutation (PT 20210)

Indications: - hypercoagulability - deep vein thrombosis Contraindications: - routine testing not indicated in offspring of patients with factor V Leiden mutation [1] Clinical significance: 1) most common genetic risk factor for venous thrombosis - least thrombogenic of genetic risk factors [1] 2) 5-7% of the general white population is heterozygous for the factor V Leiden mutation - most heterozygous patients are asymptomatic 3) occurs in up to 15% of Greek population 4) occurs almost exclusively in white population 5) 20% of patients with 1st thrombosis will have the factor V Leiden mutation 6) 50% of patients with recurrent spontaneous thromboses will have the factor V Leiden mutation - heterozygousity for factor V Leident mutation only confers 1.5 fold risk of recurrent DVT [1] 7) heterozygotes have roughly 3 to 5-fold increased risk of thromboembolism [1,3] a) absolute 10 year risk is 0.7% if 1] < 40 years of age 2] BMI < 25 kg/m2 3] NON smoker b) absolute 10 year risk is 10% if 1] > 60 years of age 2] BMI > 30 kg/m2 3] smoker 8) homozygotes have roughly 15 fold increased risk of thromboembolism [3] a) absolute 10 year risk is 3% if 1] < 40 years of age 2] BMI < 25 kg/m2 3] NON smoker b) absolute 10 year risk is 51% if 1] > 60 years of age 2] BMI > 30 kg/m2 3] smoker 9) not a factor in atherothrombotic events (arterial thrombosis) [6] Principle: - the Leiden mutation affects the factor V gene (chromosome 1) mRNA base 1691 from G to A & the protein amino acid 506 from Arg to Gln - this results in the factor V protein being resistant to inactivation by activated protein C - the mutation is detected by amplification of exon 10 from the gene followed by RFLP analysis of an MnI site also affected by the mutation - genetic variation can affect the analysis, thus clinical correlation is important Specimen: whole blood, lavender top. Minimal volume 3 mL. Storage: room temperature (includes shipping) 3) Method: PCR, RFLP.

Related

activated protein C (APC) resistance coagulation factor V; activated protein C cofactor; proaccelerin, labile factor; contains: coagulation factor V heavy chain; coagulation factor V light chain (F5)

General

factor V (F5) gene mutation point mutation

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018.
  2. Journal Watch 21(20):159, 2001 Middeldorp S et al, Ann Intern Med 135:322, 2001 PMID: 11529695
  3. Journal Watch 24(7):55, 2004 Juul K et al, Ann Intern Med 140:330, 2004 PMID: 14996674
  4. ARUP Consult: Factor V Leiden (F5) R506Q Variant https://arupconsult.com/ati/factor-v-leiden-f5-r506q-variant
  5. ARUP laboratories Panel of 6 tests Laboratory Test Directory ARUP: 30133 - Mini Panel of 2 tests: APC Resistance . Factor V Leiden by PCR Laboratory Test Directory ARUP: 30192 - Factor V Leiden (F5) R506Q Mutation Laboratory Test Directory ARUP: 97720
  6. Mahmoodi BK et al. Association of factor V Leiden with subsequent atherothrombotic events: A GENIUS-CHD study of individual participant data. Circulation 2020 Jul 13; PMID: 32654539 https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.119.045526

Component-of

thrombophilia (hypercoagulability) molecular diagnostic panel