Is Factor V Leiden hereditary?

Factor V Leiden is an inherited genetic condition caused by a specific mutation in the F5 gene that increases an individual's risk for developing abnormal blood clots.

Inheritance and Genetic Patterns

Factor V Leiden is a hereditary condition, meaning it is passed down from parents to children through DNA. The mutation follows an autosomal dominant pattern of inheritance, although it is often described as having "incomplete dominance." This means that inheriting just one copy of the mutated gene from one parent (heterozygous) increases your risk of clotting, while inheriting two copies (homozygous)—one from each parent—significantly elevates that risk further. Because it is autosomal, the condition affects both males and females equally, and it is not linked to sex chromosomes.

Risk and Genetic Testing

If one parent carries one copy of the Factor V Leiden mutation, there is a 50% chance they will pass the gene to each child. Genetic testing is available via a simple blood test that analyzes DNA to identify the specific F5 gene variant. Testing is generally not recommended for the general population; instead, it is typically reserved for individuals who have already experienced an unexplained blood clot, or those with a very strong family history of venous thromboembolism (VTE). De novo (spontaneous) mutations for Factor V Leiden are extremely rare; the vast majority of cases are inherited from a parent.

Genetic Counseling and Family Planning

For those planning a pregnancy, genetic counseling is a valuable resource. A counselor can help assess your specific risk level based on whether you are heterozygous or homozygous for Factor V Leiden. They can also discuss how the hormonal changes of pregnancy, which naturally increase clotting risk, interact with your genetic predisposition. While prenatal diagnosis is technically possible, it is rarely performed for this condition because Factor V Leiden is considered a manageable risk factor rather than a condition that requires intervention in utero. Understanding your genetic status allows you and your hematologist to create a proactive management plan to ensure safety during high-risk periods like surgery, long-distance travel, or pregnancy.

Medical Disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment. Always seek the advice of your hematologist or a qualified healthcare provider with any questions regarding your health or genetic status.

References

• NIH Genetic and Rare Diseases Information Center (GARD)


• Orphanet: The portal for rare diseases and orphan drugs


• OMIM (Online Mendelian Inheritance in Man): Factor V Leiden variant