Frequency and heredity of ADA types in the Polish population

Phenotypes of the ADA system were determined in a population sample of n = 208. Two ADA phenotypes were encountered: ADA 1-1 with a frequency of 0-82, and ADA 2-1 with a frequency of 0-18. Gene frequencies were: ADA1 = 0-911 and ADA2 = 0-089. Distribution of phenotypes in 9 families with 28 children and in 93 mother-child pairs was consistent with the hypothesis of heredity of the ADA group system.