PROBLEM: We have investigated the possible role of adenosine deaminase (ADA) genetic polymorphism in human fertility through a comparative study of couples with recurrent spontaneous abortion (RSA) and healthy puerperae.
METHOD OF STUDY: Adenosine deaminase phenotype has been determined in 209 women with repeated episodes of unexplained spontaneous abortion (RSA) and their husbands, as well as in 115 healthy pregnant women from the population of Rome. An independent sample of 286 puerperae along with their newborn infants in the population of Penne was also studied.
RESULTS: The proportion of carriers of ADA*2 allele, which is associated with the lowest enzymatic activity, is lower among women with RSA than among healthy pregnant women from the same population of Rome. Preliminary observations suggest a protective effect of ADA*2 against the development of autoantibodies in RSA. Such an effect seems to be mediated by an interaction with ABO blood groups. In the population of Penne the proportion of women carrying ADA*2 allele is higher among those who have had two or more previously born children than among women with only one or no children.
CONCLUSIONS: The data suggest that women carrying the ADA*2 allele are better protected against the spontaneous loss of embryos and have a higher fertility rate.