Differentiation of the Factor VII Complex

Polycythaemia vera and Christmas disease with slightly prolonged prothrombin time

A family is reported in which Christmas disease in one member and polycythaemia in another were associated with prolongations of the one-stage prothrombin time of the factor-VII deficiency type. Changes in the prothrombin time were present in the siblings of the case of Christmas disease and in a number of unrelated cases of polycythaemia vera. The use of "mixing procedures" did not reveal any significant mutual correction of the changes in prothrombin time.

[Clinical studies of familial hereditary factor VII deficiency (author's transl)]

The discovery of a severe factor VII deficiency with increased bleeding tendency resulted in investigations of 22 members of the family. In the propositus and in two of his siblings a severe hypoproconvertinemia was demonstrated, a partial deficiency was found in ten persons. Studies of the family confirmed that this disorder is transmitted by an autosomal gene with intermediate penetrance. The mutated gene produces a severe deficiency in the homozygote and partial deficiency in the heterozygote. The parents of the homozygote patients were consanguineous. Hemorrhagic diathesis was noted only in patients with a severe factor VII deficiency. Causes for the variability of the clinical manifestations are discussed.