Objective: A genetic variation in the androgen receptor (AR) has been associated with the risk of developing endometriosis. The AR gene is located on the X chromosome and contains a highly polymorphic trinucleotide repeat (cytosine, adenine, and guanine: CAG) in its first exon, whose length and methylation pattern affect both AR expression and function. Thus, we sought to further investigate the potential association between endometriosis and the AR-CAG polymorphism.
Methods: Genomic DNA was obtained from a consecutive series of 197 white Italian women of reproductive age who underwent laparoscopy for benign gynecologic pathologies. Molecular analysis of AR-CAG repeats was performed by polymerase chain reaction amplification and Genescan evaluation. The pattern of CAG repeat distribution was compared between subjects with and without endometriosis.
Results: Endometriosis was documented in 105 women (stage I-II in 33 women and stage III-IV in 72 women). We found no difference in the number of AR-CAG repeats between women with endometriosis and controls. The CAG repeat length ranged from eight to 27 (mean +/- standard deviation, 17.4 +/- 1.9) for endometriosis patients and from 11 to 27 (mean +/- standard deviation, 17.4 +/- 2) for controls. Moreover, no association was found between AR gene polymorphisms and the various clinical manifestations of the disease.
Conclusion: We conclude that AR-CAG repeat length does not constitute an important factor for the genetic predisposition to endometriosis.