Association of androgen receptor GGN repeat length polymorphism and male infertility in Khuzestan, Iran.

BACKGROUND: Androgens play critical role in secondary sexual and male gonads differentiations such as spermatogenesis, via androgen receptor. The human androgen receptor (AR) encoding gene contains two regions with three nucleotide polymorphic repeats (CAG and GGN) in the first exon. Unlike the CAG repeats, the GGN has been less studied because of technical difficulties, so the functional role of these polymorphic repeats is still unclear. OBJECTIVE: The goal of this study was to investigate any relationship between GGN repeat length in the first exon of AR gene and idiopathic male infertility in southwest of Iran. MATERIALS AND METHODS: This is the first study on GGN repeat of AR gene in infertile male in Khuzestan, Iran. We used polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis to categorize GGN repeat lengths in 72 infertile and 72 fertile men. Afterwards we sequenced the PCR products to determine the exact length of GGN repeat in each category. Our samples included 36 azoospermic and 36 oligozoospermic men as cases and 72 fertile men as control group. RESULTS: We found that the numbers of repeats in the cases range from 18 to 25, while in the controls this range is from 20 to 28. The results showed a significant relation between the length of GGN repeat and fertility (p=0.015). The most frequent alleles were alleles with 24 and 25 repeats respectively in case and control groups. On the other hand no significant differences were found between Arab and non-Arab cases by considering GGN repeat lengths (p=0.234). CONCLUSION: Due to our results, there is a significant association between the presence of allele with 24 repeats and susceptibility to male infertility. Therefore this polymorphism should be considered in future studies to clarify etiology of disorders related to androgen receptor activity.

SLC30A8 gene polymorphism (rs13266634 C/T) and type 2 diabetes mellitus in south Iranian population.

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder which is characterized by chronic hyperglycemia. T2DM is due to the interplay of genetic susceptibility and environmental factors. Zinc is an important element for insulin storage and secretion. Zinc transporters ensure zinc transportation across the biological membranes and enable the cellular flow of zinc into the extracellular matrix or the intracellular vesicles. Solute carrier family 30 member 8 (SLC30A8) gene encodes zinc transporter protein member 8. The rs13266634 C/T polymorphism in SLC30A8 gene has been reported with higher risk of T2DM in literature. Thus, the present study aimed to investigate the association between rs13266634 polymorphism and T2DM in Fars province, Southern Iran and compare the results with other populations. A total of 306 subjects were collected from the outpatients of Shahid Motahhari clinic affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. These subjects were genotyped using polymerase chain reaction-restriction fragment length polymorphism and validated by direct sequencing. The frequency of CC genotype in diabetic and control groups was 90 (59.6%) and 89 (57.4%). The number of CT genotype was 51 (33.8%) in the case and 49 (31.6%) in the control group. The TT genotype was 10 (6.6%) and 17 (11%) in diabetic and non-diabetic subjects, respectively. No significant difference was found between the normal and T2DM subjects regarding the allelic and genotypic distribution (p=0.35, OR=1.19, 95% CI 0.82-1.7) and (p=0.94, OR=1.7, 95% CI 0.7-3.9). No significant difference was found between the normal and diabetic subjects regarding the rs13266634 C/T polymorphism in SLC30A8 gene. In comparison with other ethnic groups, the C allele frequency in our population was very similar to that of the European but higher than that of the Eastern Asian and lower than the African populations.

The investigation of allele and genotype frequencies of human C3 (rs2230199) in south Iranian population.

The complement system is an important mediator of natural and acquired immunity. The complement system genes coding complement proteins have polymorphisms. Hereditary deficiencies of this system predispose to autoimmune conditions such as age-dependent macular degeneration or impairment of immunity against microorganisms. When different populations are compared, the frequency of complement polymorphism shows a very marked geographical distribution. The frequency of the functional polymorphism rs2230199 (Arg80Gly; C > G) in the C3 gene was determined in population from south of Iran (n = 200), using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). One hundred thirty-eight persons (69 %) were homozygous for C allele (CC or SS); fifty-six person (28 %) heterozygote GC (FS) and six people were homozygous for G allele (GG or FF) (3 %). The allele frequency was 82 % for C3S and 18 % for C3F. A distribution of C3C allele frequency in our population is different from the reports of Asians (100 %); Indians (90-98 %); African-American (93 %); Africans (99 %) and south Brazilian (97 %). However, this finding is similar with the findings Caucasian (80-82 %) ( http://www.ncbi.nlm.nih.gov/SNP ); Americans (80 %); Pushtoon, Hazaras, Osbek and Tajik ethnic groups in Afghanistan (88-90 %) and Tunisian population (84 %). Our study confirmed significant inter-ethnic differences in C3 (rs2230199) frequencies between south Iranians and other ethnic groups. The analysis of genetic variation in complement genes is a tool to provide new insights into the evolution of the human immune system.