The DAZ-like (DAZL) gene located on the short arm of autosomal chromosome 3 (3p24), an essential master gene for the premeiotic development of male and female germ cells, is the father of the Y-chromosome DAZ gene cluster and encodes for RNA-binding proteins. Reported instances of positive association of DAZL gene mutations with infertility in men have been found in a Taiwanese population but not in Caucasians. There is no study from Tamil Nadu, South India, to demonstrate the role of DAZL gene in male infertility; we, therefore, analyzed a total of 287 men, including 147 infertile and 140 normozoospermic fertile controls from rural areas of Tamil Nadu, South India, to assess the phenotypic effect of DAZL mutations in this region of the world. Interestingly, all our samples showed absence of the A386G (T54A) mutation that was found to be associated with spermatogenic failure in the Taiwanese population. Therefore, we suggest that the A386G (T54A) mutation is not associated with male infertility in Tamil Nadu, South India.

Variations in the trinucleotide-CAG repeat number of the catalytic subunit of the mitochondrial DNA polymerase gamma (POLG) have been speculated to be associated with male infertility. The ten CAG repeats (10/10) were found to be the most common allele (88%), absence of which was found to be associated with male infertility. As no study on Indian population was conducted so far to support this view, we investigated the distribution of the POLG-CAG repeats in 509 oligoasthenozoospermic and 241 normozoospermic control Indian men from the same ethnic background. Our study suggested that the distribution of common allele (10/10) was almost similar in both infertile (75%) and normozoospermic (75.5%) men. Further, we had analysed the CAG repeat number in as many as 1306 Indian men belonging to different ethnic, geographical and linguistic backgrounds and found the common allele 10/10 at a frequency of 78.4%. Our study, therefore, suggests that the 10-CAG repeat is the most common allele present in Indian populations, but its absence and the occurrence of the other mutant homozygous (non 10/non 10) genotype should not be understood as being specific to infertility. It, thus, suggests that the POLG-CAG repeat variation is not associated with male infertility in Indian populations, and hence is not a useful marker for screening infertile men.

Purpose CAG repeat length of human miotochondrial DNA Polymerase gamma (POLG) gene is polymorphic with a major allele at 10 repeats and considered as the common allele whereas the mutant alleles (not 10/not 10 CAG repeats) were found to be associated with oligospermia / oligoasthenospermia in male infertility. To explore whether CAG trinucleotide repeat expansion in exon 1 of POLG gene is associated with spermatogenic failure. Methods One hundred twenty four infertile men (sperm count <20 million/ml) and 60 normozoospermic (sperm count >20 million/ml) control Indian men of Tamil Nadu, were enrolled. DNA was extracted from 10 ml of peripheral blood and from semen using standard procedures. CAG repeat expansion was analyzed by polymerase chain reaction. Amplified products were quantified by 2 % agarose gel electrophoresis and subjected to genescan analysis to ascertain the size of POLG-CAG alleles. Results This analysis interestingly revealed that the common allele 10 (10-CAG repeats) was widespread in infertile and normozoospermic control men with a frequency of 79 % and 71.7 % respectively. No statistical significance was found in POLG genotypic frequency distribution between infertile men and normospermic men. Conclusion The present study confirmed no association between the POLG gene polymorphism and male infertility. Thus, if associated with infertility, the POLG gene polymorphism should be only considered as a minor possible contributing factor in infertile male patients with no impact on obtaining a pregnancy.

Decline in fertility rate is alarming and it affects about 15.0 % of couples trying to conceive. Globally, 5.0-7.0% of the general male population is affected by infertility and the trend may increase in future. Diabetes mellitus, a state of chronic hyperglycemia, is found to be an effective cause associated with male infertility. Since both type I and type II diabetes influences male infertility, we aimed to identify the genetic link underlying diabetic male infertility. Y chromosome microdeletions were screened in 12 Type I & Type II diabetic infertile male patients of varying seminogram profile by employing Triplex (sY84, sY99 and sY156) and individual (sY86, sY100, sY134 and sY254) PCR. sY156 STS marker of AZFc region was invariably deleted in 5 diabetic infertile men in addition to sY86, sY100, sY134 STS markers. No functional gene has been assigned for the 923bp DNA fragment encoded by the sY156 STS marker. Rather, it belongs to a processed pseudogene TRIM60P8Y. Frequent deletion of sY156 marker in AZFc region in diabetic infertile men is unclear. The result showed can be further substantiated with more number of samples.

A case-control study conducted on fertile and infertile men in Coimbatore population. The study, aimed to identify and associate the following two single nucleotide polymorphisms (SNPs) rs2030259 and rs5911500 in genes KDM3A (lysine (K)-specific demethylase 3A) and LOC203413.The SNPs were identified by restriction fragment length polymorphism (RFLP) technique in 17 normospermic individuals and in 13 infertile males (9 oligospermic and 4 azoospermic) and results were analysed using fisher's exact test. Although the polymorphisms were found in both fertile and infertile men, no significant association is found for both 2 SNPs with infertility from the samples observed.