Y Chromosome Deletions in Azoospermic Men in India

Abstract

Genetic factors cause about 10% of male infertility. Azoospermia factors (AZFa, AZFb, AZFc) are considered to be the most important for spermatogenesis. We therefore made an attempt to evaluate the genetic cause of azoospermia, Y chromosome deletion in particular, in Indian men. We have analyzed a total of 570 men, including 340 azoospermic men and 230 normal control subjects. DNA samples were initially screened with 30 sequence-tagged site (STS) markers representing AZF regions (AZFa, AZFb, AZFc). Samples, with deletion in the above regions were mapped by STS walking. Further, the deletions were confirmed by Southern hybridization using the probes from both euchromatic and heterochromatic regions. Of the total 340 azoospermic men analyzed, 29 individuals (8.5%) showed Y chromosome deletion, of which deletion in AZFc region was the most common (82.8%) followed by AZFb (55.2%) and AZFa (24.1%). Microdeletions were observed in AZFa, whereas macrodeletions were observed in AZFb and AZFc regions. Deletion of heterochromatic and azoospermic regions was detected in 20.7% of the azoospermic men. In 7 azoospermic men, deletion was found in more than 8.0 Mb spanning AZFb and AZFc regions. Sequence analysis at the break points on the Y chromosome revealed the presence of L1, ERV, and other retroviral repeat elements. We also identified a approximately 240-kb region consisting of 125 bp tandem repeats predominantly comprised of ERV elements in the AZFb region. Histological study of the testicular tissue of the azoospermic men, who showed Y chromosome deletion, revealed complete absence of germ cells and presence of only Sertoli cells.

Comparative Study of AZF Deletions and TSPY Gene Variation in Czech and Indian Infertile Men

“…66.6% AZFc deletions amongst the cases with AZF deletions, as seen for both population groups, is in agreement with the reports of Hopps et al (2003). However, Thangaraj et al (2003) reported high incidence of 82.8%. McElreavey et al (2000) have observed that deletions involving the AZFc region are the most frequent amongst all the AZF deletions.…”

“…Concurrent to these, OkutmanEmonts et al (2004) and Machatkova et al (2003) also did not find any AZFa deletion among their 71 Turkish and 198 Czech cases, respectively. Least frequencies of AZFa deletions among azoospermic men have been reported among Russians (Loginova et al 2003), Chinese (Yang et al 2003), North Americans (Hopps et al 2003), Indians (Thangaraj et al 2003) and Japanese (Kihaile et al 2005).…”

Clinical and laboratory evaluation of idiopathic male infertility in a secondary referral center in India

“…The reason is probably the strict selection criteria applied in our study as well as geographic and ethnic differences. Within India, studies have been carried out in different regions, which showed a frequency between 5% and 9.5% (21)(22)(23). The selection criteria in these were also different from the criteria used in our study, the number of STSs used were variable.…”

Male infertility in Northeast China: molecular detection of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome

“…No consensus has yet been reached about the optimal number of STSs that should be used, or the specific loci that should be imperatively screened (Choe et al, 2007). Some authors have suggested that using more sets of primers increases the chances of detecting microdeletions (Thangaraj et al, 2003;Mitra et al, 2006). On the other hand, other studies have shown that the prevalence of microdeletions detected did not increase with increasing numbers of STSs used (Choe et al, 2007).…”