Gordon, Hymie

SUMMARY Factor VIII concentrations in plasma, platelet retention, and ear bleeding times were determined on 35 normal pigs, 40 obligate carriers of porcine von Willebrand's disease, and 25 bleeders. The bleeders could be distinguished from the normal pigs by each of the 3 tests. At most, only one-third of the carriers could be distinguished from the normal pigs by any one test. A hemostatic score, derived from the results of the 3 tests, increased the discrimination to slightly more than half. The degrees of abnormality on the 3 diagnostic tests seemed to vary from family to family and might have been related to the sire of the bleeder.

Atrial septal defect (ASD) of the fossa ovalis type was found in 16 members of one family and confirmed in 15 members at autopsy or surgery or by cardiac catheterization. Sinus rhythm was present in 12 affected members, 11 of whom had electrocardiographic evidence of prolonged atrioventricular (A-V) conduction. Five other family members without ASD also had prolonged A-V conduction. The pedigree chart suggests that the syndrome ASD with prolonged A-V conduction is the manifestation of a single mutant autosomal gene with dominant effect, a high degree of penetrance, and some variation in expressivity. Earlier reports of familial ASD showing the autosomal-dominant pattern of inheritance reveal a similar frequency of prolonged A-V conduction among affected persons. The great majority of cases of ASD are sporadic, with little likelihood of recurrence in subsequent sibs or children. We suggest, however, that when ASD of the fossa ovalis type is accompanied by prolonged A-V conduction, the genetic prognosis may be drastically changed to a risk of almost 50% that the condition will recur in subsequent sibs or children of affected persons.