Disputed parentage due to exchanged babies solved by HLA.

Two female newborns were suspected of having been exchanged. Each baby was tested for blood groups ABO, Rh and MN; for isoenzymes ADA, AcP1, GLO, PGM1, AK1 and for Hp; and for HLA-A and B phenotypes. In family 1 the baby girls was excluded on the basis of ADA, GLO, PGM1, AK1, Hp and HLA phenotypes. In family 2 the baby girl was excluded on the basis of Rh, PGM1, Hp and HLA phenotypes. Yet the phenotypes of each girl did fit with the parents of the other family. The odds for the babies to belong to the other families were 6.9 X 10(5):1 and 2.5 X 10(6):1. It could be seen that the odds obtained by HLA testing were much higher, usually by two or more orders of magnitude than those of each of the other marker systems. This makes the HLA an excellent single test for the resolution of disputed parentage. The odds of the simultaneous occurrence of 2 children each assigned to the other family was calculated to be 1.7 X 10(12):1.