Familial hyper-alpha-lipoproteinemia in 26 kindreds.

The inheritance of familial hyper-alpha-lipoproteinemia was investigated in 161 individuals in 11 black kindreds and 15 white kindreds. After age and sex adjustment, the distribution of high density lipoprotein-cholesterol (C-HDL) in the relatives of probands was examined for evidence of bimodality. In whites, bimodality appeared to be present, with one mode at about 46 mg/dl and the other at about 69 mg/dl. In blacks, there was little convincing evidence of bimodality. In the white kindreds, it appeared that one factor with a relatively large effect is causing the familial aggregation of high C-HDL levels; this factor could be a major gene.