ABSTRACT
DAZL (deleted in azoospermia-like) 260A>G and MTHFR (methylene tetrahydrofolate reductase) 677C>T are two important autosomal variants associated with impaired spermatogenesis. In this study, we investigated DAZL 260A>G and MTHFR 677C>T variants in sperm DNA and their frequency in oligozoospermic infertile men of Indian origin. The study on sperm DNA was performed, since it is more prone to oxidative stress-induced damage and mutation. One hundred oligozoopsermic infertile men having normal chromosomal complement with intact Y chromosome and 100 age- and ethnically-matched fertile controls were investigated for these variants in their sperm genome. Spermatozoa were separated by gradient centrifugation and DNA was isolated and analyzed for the single nucleotide polymorphisms (SNPs) by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The results showed no significant differences in the frequency of DAZL AG (P = 0.58) and MTHFR CT (P = 0.44) between oligozoospermic infertile men and controls. However, 8% (8/100) oligozoospermic infertile men harbored both the variants and showed significantly (P<0.0001) lower sperm count (3.28 ± 1.1 vs 12.50 ± 4.09) compared to infertile men with either of the single variant. None of the fertile controls showed the presence of the both variants. In conclusion, the combined effect of both DAZL 260A>G and MTHFR 677C>T variants may have role in compromised sperm count. However, further studies are required to find the pathological role of these combined variants in male infertility.
Subject(s)
Base Sequence , DNA Primers , Humans , Infertility, Male/genetics , Male , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , RNA-Binding Proteins/genetics , Spermatozoa/ultrastructureABSTRACT
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.