Strong association between angiotensin I-converting enzyme I/D polymorphism and unexplained recurrent miscarriage of Chinese women--a case-control study.

The patients with recurrent miscarriage (RM) undergo multiple diagnostic tests to detect parental chromosomal anomalies, maternal thrombophilic, endocrine, or immunological disorders, and over 50% of the cases with RM are classified as idiopathic unexplained RM (URM). Angiotensin I-converting enzyme (ACE) is proposed to be a candidate gene in many common diseases, and the plasma ACE levels was associated with an insertion (I)/deletion (D) polymorphism involving about 287 bp situated in intron 16 of the ACE gene, the so-called ACE/ID polymorphism. In this study, we have estimated the ACE I/D polymorphism within a cohort of Chinese patients with URM. There were significant differences both in allele and genotype distribution between patients with URM and healthy controls. The association to URM reached significant both in dominate (1.63-fold, D allele) and in recessive mode (1.76-fold, DD genotype). To our knowledge, the present study is the first to establish the association between ACE I/D polymorphism and the development of URM and indicates that the D allele of the polymorphism possibly be a risk factor for URM in Chinese population.