Factor XI Deficiency (F11)
Factor XI deficiency, also known as Hemophilia C, is an autosomal recessive bleeding disorder that is caused by deficiency of clotting factor XI. Factor XI is encoded by the gene F11 and is particularly common in individuals of Ashkenazi Jewish descent, although it is found in many ethnicities around the world. The bleeding symptoms are fairly moderate and bleeding episodes typically occur after surgery or trauma. There is no genotype-phenotype correlation, as the residual amount of factor XI in the blood does not correlate with the severity of the disease. Heterozygote carriers may sometimes manifest symptoms. With proper disease management, life expectancy is not reduced.
For information about carrier frequency and residual risk, please see the Expanded Carrier Screen brochure.