Azoospermia factor gene microdeletions in infertile men with non-obstructive azoospermia and normal karyotype: First case-control study from Kashmir

Abstract

BackgroundMicro-deletions in the Y chromosome are recognized as the causative factor for male infertility. The prevalence of Y chromosome micro-deletions exhibits variation among infertile males across different areas and races globally. The study of Y chromosome micro- deletions is crucial among genetic variables owing to their ability to transmit genetic defects to the progeny. Microdeletion of the azoospermia factor (AZF) region associated with the long arm of the Y chromosome (Yq) has three sub-regions (AZFa, AZFb, and AZFc) that play an important role in spermatogenesis. The genes associated with the AZF region of the Y chromosome are believed to play a crucial role in the process of spermatogenesis by performing several activities such as gene silencing, transcription, ubiquitination, and maintenance of microtubule networks. Due to the absence of epidemiological research on Y chromosome micro-deletions in ethnic infertile male population of Kashmir, our study sought to examine the Y chromosome micro-deletions among non-obstructive azospermic infertile men in Kashmir. ObjectiveThe research was aimed to establish the frequency and characteristics of micro-deletions in the AZF region of Y chromosome in infertile males of our population with non-obstructive Azoospermia and normal Karyotype. MethodsA total of 120 subjects were included in the study. Samples from 60 male patients with fertility issues (non-obstructive azoospermia) and an equal number of samples from normal men having established fatherhood (biological fathers) were taken for the study. The average age in years of cases and controls were 32.80 and 34.88 respectively. A total of 26.66 % of cases and 13.33 % of controls were found to be consanguineous, 36.66 % of cases and 40 % of controls were urban while 63.33 % of cases and 60 % of controls were from rural population. Molecular analysis was performed by multiplex polymerase chain reactions (PCR) using sequence tagged sites (STS) from 3 different regions of AZF of Y chromosome. To assess the frequency of AZF micro-deletions, molecular analysis was performed by multiplex polymerase chain reactions (PCR) using sequence tagged sites (STS) from 3 different regions of the Y chromosome (sY84 and sY86 for AZFa region; sY127 and sY134 for AZFb; sY254 and sY255 for AZFc region). ResultsIn the present study a total of 9 out of 60 cases (15 %) were found to have Y chromosome micro- deletions in AZF region of Yq arm. The most frequent micro deletions were observed in AZFb region, 8 out of 60 cases (13.33 %) from AZFb region were found to have deletions.5 out of 60 cases (8.33 %) were reported with deletions associated to AZFc region region and 6.66 % of cases were found to harbor deletions in both AZFb and AZFc region. However no deletion was reported in the AZFa region in all the studied cases. No micro-deletions were reported in the controls during the study. ConclusionThe study represents the first report on the incidence of Y chromosome microdeletions in infertile men from our population. The findings from the present study indicate the prevalence of these gene microdeletions as a major contributing factor to the etiology of infertility in males. This study emphasizes that the multiplex PCR based screening is a reliable method in ruling Y chromosome micro deletions as a factor in the pathogenicity of male infertility and recommends genetic testing prior to planning of any reproductive assistance.