On the genetics of the human serum paraoxonase (EC 3.1.1.2).

Incubation of the sera of 799 nonrelated persons with paraoxon led to varying degrees of inhibition of the serum cholinesterase (EC 3.1.1.8) with residual activity between 0% and 67.4% of the initial activity. This is the result of a differing paraoxonase (EC 3.1.1.2) activity. The residual activities show a trimodal distribution. The results of studies of 99 families with children show that an autosomal dominant herdity factor is most likely. Consideration of the constellations of the activity values within the families can thus yield a stochastic external criterion. This, together with the shape of the distribution of the individual values, gives good statistical estimates for the distributions and frequencies of the three groups obtained by an iteration technique. Tests of association that take account of group membership show that residual activity does not depend on the blood groups A, B, O, and Rh, or on age. A conclusive argument for our assumption of three activity groups is that the resulting group frequencies are consistent with the Hardy-Weinberg rule.