Genetic and epigenetic effects in sex determination.

Sex determination is a complex and dynamic process with multiple genetic and environmental causes, in which germ and somatic cells receive various sex-specific features. During the fifth week of fetal life, the bipotential embryonic gonad starts to develop in humans. In the bipotential gonadal tissue, certain cell groups start to differentiate to form the ovaries or testes. Despite considerable efforts and advances in identifying the mechanisms playing a role in sex determination and differentiation, the underlying mechanisms of the exact functions of many genes, gene-gene interactions, and epigenetic modifications that are involved in different stages of this cascade are not completely understood. This review aims at discussing current data on the genetic effects via genes and epigenetic mechanisms that affect the regulation of sex determination. Birth Defects Research (Part C) 108:321-336, 2016. © 2016 Wiley Periodicals, Inc.

Smoking and Male Infertility: An Evidence-Based Review.

Many studies have reported that the contents of cigarette smoke negatively affect sperm parameters, seminal plasma, and various other fertility factors. Nevertheless, the actual effect of smoking on male fertility is not clear. The effect of smoking on semen parameters is based on the well-established biological finding that smoking increases the presence of reactive oxygen species, thereby resulting in oxidative stress (OS). OS has devastating effects on sperm parameters, such as viability and morphology, and impairs sperm function, hence reducing male fertility. However, not all studies have come to the same conclusions. This review sheds light upon the arguable association between smoking and male fertility and also assesses the impact of non-smoking routes of tobacco consumption on male infertility. It also highlights the evidence that links smoking with male infertility, including newly emerging genetic and epigenetic data, and discusses the clinical implications thereof.

An epileptic case with mosaic ring chromosome 6 and 6q terminal deletion.

Ring chromosomes are rare chromosome disorders that arise usually de novo. Children with ring chromosome 6 have a wide range of intellectual functioning and congenital anomalies. We report an epileptic case of a 10-year-old boy to be mild psychomotor retardation and dysmorphic traits including microcephaly, brachycephaly, flat occiput, large and apparently low set ears, and bilateral syndactyly between his second and third fingers with mosaic ring chromosome 6 and 6q terminal deletion. Peripheral chromosome and fluorescent in situ hybridisation (FISH) analysis of the patient showed mos46,XY,r(6)(p24;q26),del(6)(q27) [30]/46,XY,del(6)(q27) [20] de novo. We presented the patient in the light of literature because the mosaic ring 6 and 6q terminal deletion was different caryotypically from other mosaic ring 6 patients.

Association of the polymorphisms in promoter and intron regions of the interleukin-4 gene with chronic periodontitis in a Turkish population.

OBJECTIVES: The etiology of periodontitis is related to the interaction between micro-organisms and host responses. Host modifying factors, such as genetic predisposition, may increase the severity of periodontitis. Recent works have shown that the levels of cytokine expression are regulated by genetic polymorphisms, and that these variations can interfere with progression of the disease. This study therefore aimed to evaluate whether interleukin (IL) 4 gene polymorphisms are associated with severe generalized chronic periodontitis. MATERIAL AND METHODS: Seventy-five severe generalized chronic periodontitis patients and 73 healthy subjects were examined. Blood samples were taken and genomic DNA was amplified by polymerase chain reaction (PCR). Identification of 70 base-pair repeat polymorphisms in intron 2 and C-->T polymorphisms at -590 position of the promoter region was performed through PCR-restriction fragment length polymorphism (RFLP). RESULTS: No significant differences were found in the allele and genotype frequencies between the control and periodontitis group. CONCLUSION: The IL-4 polymorphisms were not related to severe generalized chronic periodontitis in a Turkish population.

Lack of evidence for association between endothelial nitric oxide synthase gene polymorphism (glu298asp) with Behçet's disease in the Turkish population.

Endothelial nitric oxide synthase (eNOS) could be a candidate gene for Behçet's disease (BD). This study investigated the relationship of the eNOS Glu298 --> Asp polymorphism with the presence and severity of BD in the Turkish population. Ninety-two patients with BD and 100 controls were studied. Analyses of Glu298Asp polymorphism in exon 7 of the eNOS gene were made by the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique. The frequencies of the eNOS genotypes were similar for BD patients (GG:GT:TT = 58.7%:38%:3.3%) and controls (59.2%:33.7%:7.1 %), P = 0.335. No evidence of difference was found in the frequency of the T allele between BD patients (22.3%) and controls (24%), [OR = 0.91, 95% CI (0.55-1.50), P = 0.690]. Glu298 --> Asp polymorphism of the eNOS gene does not appear to be associated with the presence of BD in the Turkish population.