INHERITED FACTOR-VII DEFECT IN A NEGRO FAMILY
A case of factor-VII deficiency of a congenital nature in a Negro male child has been reported. As far as can be determined, this is the first case reported in this race. The defect was detected at 6 hours of age. Prothrombin, as contrasted to factor VII, after initially low levels normally found in infants, rose to adult levels. The patient's one-stage prothrombin time has ranged between 25 to 35 second (normal 11 to 12 seconds). In spite of this, he has never shown any manifestations of hemorrhage. The patient's family was studied and the findings indicate that the patient's defect represented a homozygous state and that both parents with a less severe deficiency were heterozygous for the trait. The defect is an autosomal disorder directly inherited. It is clinically apparent and easily detected only in the homozygous state. The heterozygous state is characterized by a very slight prolongation of the one-stage prothrombin time, the difference from the control value being so minimal as to be overlooked. In one subject studied, an aunt of the propositus, the quantitative defect (42% of normal) could not be regularly detected by the usual methods. Only by using the plasma of the propositus as the test plasma, was the defect in her plasma detected, thus explaining the transmission of the trait to her offspring. These findings explain the difficulties previously encountered in understanding the inheritance of the disorder.