FACTOR V LEIDEN
R506Q mutation, Factor V mutation
DNA ANALYSIS
Also see: Thrombophilia Panel - DNA Analysis

Genetic risk factors are involved in the predisposition of individuals to venous thrombosis. These factors include inherited resistance to activated protein C (APC) as well as deficiencies in antithrombin III, protein C and protein S. APC resistance is a major basis for familial thrombosis and is common in the general population (2-5%). APC resistance is frequently associated with factor V Leiden, a point mutation in the factor V gene. Individuals heterozygous for this mutation have an increased risk for venous thrombosis (approximately 5- to 10-fold). Individuals homozygous for this mutation have an even higher risk for venous thrombosis (approximately 50- to 100-fold). Prophylactic anticoagulation therapy should be considered for carrier individuals at risk in situations where venous stasis is likely (i.e. prolonged bed rest after surgery).

Analysis for the Factor V Leiden R506Q mutation is offered as a specific DNA test, or as part of a Thrombophilia panel which also includes the Prothrombin (Factor II) 20210G-A mutation and the MTHFR 677 C-T variant.

Reasons for Referral:

Evaluation of patients with venous thrombosis
Evaluation of venous thrombosis in pregnant women or women taking oral contraceptives
Evaluation of female smokers with myocardial infarction under age 50
Evaluation of asymptomatic individuals with a family history of venous thrombosis
Evaluation of individuals with relatives known to have Factor V Leiden mutation
Evaluation of women with recurrent pregnancy loss, unexplained severe preeclampsia, intrauterine fetal growth retardation, or stillbirth

Testing Methodology:

Direct Mutation Analysis: Our laboratory uses DNA amplification (PCR) and an automated mini-sequencing methodology, Pyrosequencing, to test for the R506Q mutation in the Factor V gene.

Sensitivity:

Approximately 90% of APC-resistance is due to Factor V Leiden.

Specimen Requirements:

Blood: EDTA (purple-top) tubes: Adults: 14 cc; Child: 6 cc; Infant: 2-3 cc
Requisition form must accompany specimen. Prior to any genetic testing, we recommend genetic counseling and request that the subject, or their legal guardian, sign our consent form and submit it with the sample. To receive our forms and information about prenatal testing, please contact our laboratory.

Turnaround Time:

2 weeks

CPT Codes and Prices:

83914, 83912, 83898, 83891

Shipping Information

Forms:

>> DNA Requisition

Test Code:

6028