A possible autosomal dominant trait of familial recurrent spontaneous abortions and defective reproductive fitness

It has been postulated and experimentally supported that some idiopathic recurrent spontaneous abortions are caused by recessive lethal genes, probably linked to the major histocompatibility complex. The biggest problem in a trait analysis of some hereditary phenotypic characteristic or disease is genetical heterogeneity. The other problem is a possibility that the predisposition for disease is autosomal dominant characteristic, although disease is caused by recessive genes. In order to investigate genetics of idiopathic recurrent spontaneous abortions and defective reproductive fitness as a separated and unique clinical and immunologycal entity, 122 couples with two or less (44 couples), three or more (19) spontaneous abortions, blighted ovum or missed abortion (14), malformed child with or without spontaneous abortion (32) and sterility (13), were cytogenetically and genetically analysed. All gynaecological and hormonal causes are ruled out previously. Overall frequency of major chromosomal aberration is 13.1% (16/122) and 18% (22/122) for the chromosomal variants. Although, it is not still clear if the chromosomal variants or duplication of heterochromatin can interfere with reproductive fitness, those couples are also excluded because the content of heterochromatin of couples with malformed child with or without spontaneous abortion is significantly higher than in the control group (9 couples with one or more children and with no history of sp.ab.). The family pedigree of couples with familial spontaneous abortion shows vertical, no sex-related expression through several generation and no consanguinity, what leads us to conclusion that idiopathic recurrent spontaneous abortion or its predisposition has autosomal dominant trait. The next step will be to see if those genes are HLA-related or not.