While deficiency is rare, two forms exist. Both are autosomal recessive and affect both sexes. In one form the VII molecules are decreased while in the second group an abnormally formed molecule is produced. Bleeding symptoms may be severe in homozygotes and include epistaxis, ecchymoses, GI bleeding, hemarthroses, menorrhagia, and umbilical cord hemorrhage. Fatal cerebral hemorrhage may occur.
Heterozygotes are usually asymptomatic.
There are some patients reported to have thrombotic episodes. It is not clear if some of the clinical variation relates to molecular structural variants. Homozygous homocystinuria is associated with thromboembolism. Factor VII, AT III, and protein C levels have been reported as decreased in two sisters with this disease. 2 Decreased synthesis of liver produced coagulation factors may occur in homocystinuria.