Hemophilia A in a phenotypic female with normal male karyotype associated with a low factor XII level.

Hemophilia A was detected in a 40-year-old black Gabonese female prior to thoracic surgery for empyema. The diagnosis of mild hemophilia A was supported by the findings of low factor VIII coagulant activity (VIII:C 4%), normal levels of factors VIII related antigen (VIIIR:Ag) and VIII von Willebrand (VIIIR:WF), without detectable circulating anticoagulant. Neither the patient nor her immediate relatives had past histories of abnormal bleeding. The physical features were phenotypically female with developed breasts, pubic hair and normal external genitalia: however, she had primary amenorrhea, a blind vagina with no uterus and her karyotype was 46,XY. These findings are consistent with the diagnosis of testicular feminization thereby explaining the apparent contradiction between the phenotype and the known six-linked inheritance of hemophilia A. In addition to factor VIII deficiency a low level of factor XII (20%) was detected although it cannot be concluded whether the patient is truly factor XII deficient or whether she represents a low variant of the normal distribution.