Two Cases of Hemophilia A in Girls

Abstract

Two cases of hemophilia A in girls were reported. Case 1 was a 5-year-old girl who had repeated episodes of bleeding since the age of one. There was no family history of bleeding tendency. She showed a low factor VIII activity (F. VIII : C) (6%) and factor VIII antigen (F. VIII : Ag) (5.6%). Case 2 was a 6-year-old girl who had also frequent episodes of bleeding since 2 years of age. There was no bleeding tendency among her family members. She had a low F. VIII : C (4%) and F. VIII : Ag (4%). Both cases showed normal von Willebrand factor antigen (vWF : Ag), ristocetin cofactor, multimer structure of vWF and ristocetin-induced platelet aggregation, respectively. They showed normal female appearance and karyotype. No alloantibody to F. VIII in both cases was detected. F. VIII : Ag/vWF : Ag ratio of their mothers was 0.57 and 0.59, respectively. It was considered that their mothers were heterozygous carriers. Low levels of F. VIII : C in both cases may be explained by extreme lyonization of a heterozygous carrier or homozygous state by the mutation on normal paternal X-chromosome.