Excess of HLA parental sharing in families with Turner patients.

In utero selection processes are probably related to mother-father compatibility as has been reported in abortion-prone couples and in Down syndrome studies. In order to analyse this phenomenon, we investigated families with chromosomal imbalance (Turner syndrome). We chose this model because previous data indicated a high frequency of HLA-A31 and B38 in Turner patients and in their mothers. We report high HLA antigen sharing in Turner families and great histocompatibility between mother and affected daughter, not related to abortion histories. The proportion of HLA-A homozygous cases among Turner children was higher than expected. The level of lymphocytotoxic antibodies against fetus in mothers of Turner patients was comparable to that of mothers of families with normal fertility and probably favoured these pregnancies.