Einfluss des Angiotensin-Converting-Enzym-Polymorphismus auf die männliche Fertilität
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Numerous data from animal experiments have suggested a causal relationship of the ACE gene product with male infertility as well as with renal pathology. In the human, a polymorphism of the ACE gene (490bp, 190+490bp, 190bp) has been described in the context with urological abnormalities. We therefore examined whether this polymorphism might also be involved in human infertility. Ejaculates from 114 male partners from sterile couples were obtained and sperm quality was assessed according to WHO criteria. DNA was isolated from sperm cells and ACE gene polymorphism was analysed using PCR and agarose gel electrophoresis. Sperm quality and pregnancies achieved were correlated to ACE polymorphism. Chi square and Fisher’s exact test were used for statistical analysis. Eight healthy fertile control persons who had fathered a child within the last 2 years were also analyzed and compared to patients‘ results. 17 patients (14.9%) were homozygous for the 490bp polymorphism, 32 patients (28.1%) were heterozygous and 65 patients (52.6%) were homozygous for the 190bp polymorphism. The healthy controls showed a similar distribution. No significant correlation was found between ACE polymorphism and sperm quality for the entire patient group. Regarding pregnancies achieved, there was no significant correlation for the entire patient group irrespective of cause of infertility and also no significant correlation, when only couples with male infertility were analyzed. Although animal experiments suggest a causal relationship between ACE and male infertility, the (490bp, 190+490bp, 190bp) polymorphism present in humans appears to be unrelated to human procreation. Possibly, full deletion of ACE alleles or different mutations of the gene might be necessary to cause infertility in the human. At present, we are unaware whether such conditions exist.