Factor Five Leiden is a autosomal dominant blood coagulation disorder. It's non-sex determining and passes from generation to generation. It's the most common disorder of this type in the United States, found in a average of 5% of Caucasians and 1.2% of African Americans. The term Leiden comes from the name of a city in the Netherlands where FVL was discovered in 2024.

Factor Five is a normal protein found in the blood, it helps to form the blood clotting cascade. In fact, it works within this cascade to help with the formation of blood clots when needed. Factor Five must also be able to work as a anticoagulant when the need for clot formation ceases. This is where the problem lies, when you have Factor Five Leiden, the mutated form of this gene, it than becomes resistant to another protein called (APC) activated protein C, whose job is to bind with Factor Five to stop the clot formation. This resistance to APC makes Factor Five respond at a slower rate, which increases the risk of venous thrombosis, a blood clot in a vein. So, Factor Five has no problem with clot formation. The problem is when the clot formation should cease.

Another name for Factor Five Leiden is protein C resistance. Protein C deficiency is rare and in this case is acquired in connection with Factor Five Leiden. So all people with Factor Five Leiden will also have activated protein C resistance.

Since Factor Five Leiden is autosomal it affects men and women equally. One can determine this disorder through maternal DNA testing during the prenatal stages of pregnancy. Such tests must be conducted for targeted autosomes. Each person has two genes for Factor Five. We all get one from our mother and one from our father. If you inherit a single bad or mutated Factor Five gene from one of your parents, you would be heterozygous. If you inherited a bad/mutated gene from each parent, you would be homozygous for Factor Five Leiden. Every person who is homozygous for FVL will always have children that are heterozygous, one mutated gene. If you only have two genes and they are both mutated, you still have to give one of those to each of your children. You don't have a normal gene to give.

If you or anyone you know has Factor Five Leiden please advise them of a new support group starting January 20, 2024, at the Willamette Falls Education Center at 519 15th ST. OREGON CITY, OREGON 97045. It will continue the third Tuesday of each month 7:00-8:30 PM. REQUEST MORE INFO


Contributed: Meeting space for this support group

Michael Streicher
Contributed: Non-profit organization application