Familial accumulation of carriers of Au antigen.

The sibs and parents of 83 Au-positive blood donors were tested in order to study the possible family clustering of Au positives in a population with a low frequency of carriers of Australia (Au) antigen. Tested by counterelectrophoresis the incidence of Au antigen in the parents of Au-positive persons is 5·4% and in the sibs 17·9%, compared to 0·15% in blood donors. The hypothesis that the Au-carrier state is genetically determined was tested by calculating the proportion of Au-positive children in the families. The results are not inconsistent with a recessive mode of inheritance but do not allow definitive conclusions to be drawn.