Androgen Receptor Gene CAG and GGN Repeat Polymorphisms in Chilean Men With Primary Severe Spermatogenic Failure

There is ample documentation supporting the fact that androgens are required for normal spermatogenesis A minority of infertile men have abnormal testosterone blood levels or mild androgen receptor mutations We investigated the androgen receptor CAG and GGN repeat lengths in Chilean men with spermatogenic impairment We studied 117 secretory azoosper mic/oligozoospermic men (93 idiopathic and 24 excryptorchidic) without Y chromosome microdeletions, and 121 controls with normal spermatogenesis (42 obstructive and 79 normozoospermic men) Peripheral blood was drawn to obtain genomic DNA for polymerase chain reaction and automated sequencing of CAG and GGN repeats Testicular characterization included hormonal studies, physical evaluation and seminal and biopsy analysis The CAG and GGN polymorphism distributions were similar among idiopathic men excryptorchidic men and controls and among the different types of spermatogenic impairment However the proportion of the CAG 21 allele was significantly increased in idiopathic cases compared to controls (P = 012 by Bonferroni test odds ratio = 2 99 95% confidence interval 1 27-7 0) and the CAG 32 allele only was observed in excryptorchidic patients (P < 0002 Bonferroni test) Idiopathic cases with Sertoli cell only syndrome showed the highest proportion of the CAG 21 allele (P = 024 chi(2) test) On the other hand in idiopathic cases and controls the most common GGN allele was 23 followed by 24 but an inverse relation was found among excryptorchidic cases The Joint distribution of GAG and GGN in control idiopathic and excryptorchidic groups did not show an association between the 2 allele repeat polymorphisms (P > 0 05 chi(2) test) Our results suggest that the CAG 21 allele seems to increase the risk of idiopathic Sertoli cell only syndrome Moreover the GGN 24 allele could be contributing to deranged androgen receptor function associated with cryptorchidism and spermatogenic failure Key words Glutamine and glycine repeat polymorphisms male infertility Sertoli cell only syndrome