The anxiety level of an athlete is important. The serotonin transporter protein is encoded by the SLC6A4 gene. Serotonin is one of the most important members of anxiety metabolism. Serotonin transporter protein plays a role in bringing serotonin back from the synaptic space to the presynaptic neuron. We aimed to determine the genotype and allele distributions of the SLC6A4 promoter L/S polymorphism in football players and compare it with the control group. For this purpose, 20 football players participated in our study. Genotyping was performed by PCR after DNAs were isolated from buccal epithelial cells. When we examined the genotype distributions, the LL, LS and SS were found as 4 (20%), 8 (40%) and 8 (40%), respectively. In the control group, the same genotype number and percentages were determined as 10 (23%), 25 (57%) and 9 (20%), respectively. In terms of genotype distribution, no statistically significant significance was found between the two groups (p = 0.2493). When allelic distributions were examined in the athlete group, the L allele was counted as 16 (40%) and the S allele as 24 (60%). In the control group, the L allele 45 (51%) and the S allele were counted as 43 (49%). When the two groups were compared statistically in terms of allelic distribution, no statistically significant difference was found (p = 0.2423). As a result, LS and SS genotype were co-dominant and at the same time higher than LL genotype. At the same time, when we compared the S allele with the L allele, it was found that the S allele was more in percentage. Studies have found that the S allele is associated with anxiety. Sports psychologist can support athletes with S allele who are prone to anxiety problems. This is the first study to report that S allele is more common than L allele in Turkish football players.

Sports genetics studies are gaining importance day by day and the kind of exercise that athletes are prone to can be determined as a result of these studies. In our study, we aimed to analyze the rs4680 polymorphism of the Catechol-O-Methyltransferase (COMT) gene, which plays an important role in the development of athletic performance, in swimmers and young national ski runners and to compare them with the sedentary individuals. 19 ski runners, 24 swimmers and 45 sedentary individuals were enrolled for the study. Buccal cells were collected with the help of the collector swap and DNA isolations were made by using a commercially available isolation kit. Genotyping was completed by real time polymerase chain reaction (RT-PCR). Comparison of variables between groups was performed by chi-square test. According to the results, in swimmers, AG and GG genotype distributions were found as 13 (%54,17) ve 11 (%45,83), respectively, whereas same genotypes were found as  15 (% 78.95)  and 4 (%21.05), in skie runners. We detected no AA genotype in athletes. For sedentary individuals, the respective numbers of AA, AG, and GG genotypes were 4 (%8,89), 24 (%53,33) and 17 (%37,78). No statistically significant difference was determined in the terms of genotypes. When we consider the allelic distributions, in swimmers, A allele  was counted as 13 (%27.08) and G allele as 35 (67,44), whereas the same numbers for ski runners were 15 (%39.47) and 23 (%60.53) for A and G alleles, respevtively. For the sedentary group, A allele was counted as 32 (%35.56) and G allele as 58 (%64,44). For the alleles, we detected no significant difference between athletes and sedentary group. COMT rs4680 polymorphism plays an active role in the metabolism of dopamine and is an important genetic marker in determining athletic performance. To support our findings, more studies including the related polymorphisms are needed.

There are many parameters that have effects the success of athletes, like exercise, motivation, determination, nutrition, all of which have genetic backgrounds. To have the optimal approach, all of these conditions should complement each other. In this study, we aimed to analyze and compare the monocarboxyl transferase 1 (MCT1) rs1049434 polymorphism, which is important to determine the lactate levels, in long and short distance running athletes. A total of 30 athletes, 15 of which were power athletes and 15 were endurance, were enrolled for the study. DNA isolations were carried out by using commercially available DNA isolation Kit, and genotyping process was by real-time PCR. Of the 15 power athletes, 14 (93%) and 1 (7%) athletes had AT and TT genotypes, respectively. We detected no AA genotype in power athletes. In endurance cohort, 4 (27%), 8 (53%) and 3 (20%) athletes had AA, AT and TT genotypes, respectively. When we count the alleles, A allele was counted as 14 (47%) and 16 (53%) in power and endurance athletes. For T allele, 16 (53%) and 14 (47%) were counted in power and endurance cohorts. No statistically significant difference was found between groups in the terms of genotype and allele. In our cohort, AT genotype was higher in both groups, whereas both alleles were equal in our cohort. Our basic goal is to be able to channel the athlete correctly and carry it to maximum success in a shorter period of time considering the genetic predisposition.

Objective: Genetic and environmental risk factors constitute the major part of the etiology of autism, a multifactorial disorder. In this study, we aimed to investigate the MTHFR (Methyltetrahydrofolate Reductase Gene) C677T polymorphism in autistic children who were subjected to glutamate - caseinous and GAPS (Bowel and Psychology Syndrome) diets and to determine whether autism was related to decrease of enzyme activity caused by 677T allele of MTHFR gene.
Materials and Methods: Thirty autistic and 90 healthy children were included in the study. DNA was obtained using a special commercial kit (GeneAll, Korea). Genotyping was performed by PCR - RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) protocol and images were obtained by agarose gel electrophoresis.
Results and Discussion: No statistically significant difference was found in the MTHFR 677T allele frequency as 13.33% in the patient group and 19.4% in the control group as p = 0.285. Due to the fact that the number of patients included in the study was not desired and not homogeneous, we recommend looking at MTHFR A1298C polymorphism and COMT (catechol-O-methyltransferase), BDNF (brain-derived neurotrophic factor), PTEN (phosphate and tensin homolog) genes.

One of the most important members of serotonin metabolism is serotonin transporter (5HTT), which takes the serotonin back from the synaptic cavity into the presynaptic neuron (reuptake). This protein is encoded by the SLC6A4 gene and the functional deletion / insertion mutation in the promoter region of this gene affects the transcription rate. The “S” allele is referred to be the short form of the gene and studies in this field reported its relationship with anxiety. In the present study, we aimed to determine the distribution of the short (S) and long (L) alleles of SLC6A4 gene in 44 young, successful and healthy Turkish male soccer players. Genotyping process was completed by conventional polymerase chain reaction (PCR) after DNA isolation. According to the results, 10 (23%) of the players had LL, 25 (57%) had LS and 9 (20%) had SS genotypes. In the allele distributions, L allele was counted as 45 (51%) and S allel as 43 (49%). It has been reported that SLC6A4 alleles show large variation in individuals with neuropsychiatric disorders compared to the healthy individuals. This is the first study to report that LL genotype and L allele are more frequent than SS genotype and S allele in Turkish young professional soccer players

Studies to date have shown the contribution of an athletes’ genetic endowment in athletic performance. Although these studies revealed that cognitive abilities influence athletes’ competitive performance, there are only a few studies trying to investigate the association between genetic polymorphisms, which is associated with cognitive ability, and athletic performance. In the present study, we aimed investigate the link between dopamine receptor-2 (DRD2) gene rs1800497 polymorphism, which is known to exert influences on brain dopaminergic system and athletic performance of volleyball players and bodybuilders. In this regard, we enrolled 9 female volleyball players and 15 active bodybuilders in the study. Real-time PCR methodology was used for genotyping. The respective numbers and percentages of A1A1, A1A2 and A2A2 genotypes in bodybuilders were 2 (13%), 1 (7%) and 12 (80%). All the volleyball players had A2A2 genotypes. The results have revealed that addiction related A1 allele is underrepresented in volleyball players and bodybuilders. These first findings indicate that the polygenic or multifactorial mechanism may explain effect of cognitive abilities in athletes’ performance.