PHENOTYPIC RANGE OF HEMOPHILIA-A CARRIERS

Abstract

A small kindred with X-linked hemophilia A was described. It was ascertained through a clinically affected female, the daughter of a man with moderately severe hemophilia. The pedigree and the proband''s phenotype suggested a heterozygote in whom most of the normal alleles at the VIII-1 locus are not active. She had 2 sisters, also obligatory carriers. The 3 sisters exhibited the 3 phenotypes possible for heterozygous females: clinically affected, clinically normal but phenotypically abnormal as determined by laboratory tests, and clinically and phenotypically normal.