Factor X deficiency is a rare inherited bleeding disorder that causes abnormal blood coagulation, resulting from a shortage of the plasma protein factor X. Factor X is one of the vitamin K-dependent serine proteases, playing a crucial role in the coagulation cascade, as the first enzyme in the common pathway of thrombus formation. It is estimated that Factor X deficiency affects 1 individual per 500,000-1,000,000 population worldwide. Factor X deficiency is inherited as an autosomal recessive trait; with heterozygotes most often remaining clinically asymptomatic. The clinical phenotype is of variable hemorrhagic symptoms in homozygous individuals, including easy bruising, hematuria, hemarthroses, soft tissue hemorrhages, menorrhagia, and recurrent epistaxis.
Factor X deficiency is associated with mutations in F10 gene, which encodes coagulation factor X.