Factor V Leiden

Question 1

What is Factor V Leiden

Answer 1

A clotting factor that causes venous thrombosis. It can cause complications in pregnancy and MI in young females who smoke.

Question 2

Who should be tested?

Answer 2

• anyone younger than 50 with an venous thrombosis
• Venous thrombosis at unusual sites; hepatic, mesenteric, cerebral)
• Recurrent venous thrombosis
• Venus thrombosis and a strong family hx of thrombotic disease
• Venous thrombosis during pregnancy or while taking oral contraceptives
• Relatives of individuals with venous thrombosis under 50
• MI in female smokers under 50

Question 3

Testing methods

Answer 3

Patients who test positive through functional assays should have DNA studies ordered to assess heterozygous or homozygous status. Heparin therapy and lupus can confound test and these patients should proceed to genetic testing.

Question 4

Risk factors and screening

Answer 4

it is not recommended that engagement in a risk factor be an indication for genetic testing.

Question 5

Risks associated with a mutation

Answer 5

Risk for venous thrombosis is increased 7x in heterozygous carriers. There is a 20x increased risk in homozygous mutation carriers.