Lack of association between the C276T polymorphism of the neuronal nitric oxide synthase gene and migraine.

A migraine attack is a spectacularly complex brain event that can produce a wide array of neurological and systemic symptoms. The molecular mechanisms and genetics of migraine have not yet been clarified. The objective of this study was to analyze the genotype distributions and allele frequencies for the C276T polymorphism of the neuronal nitric oxide synthase (nNOS) gene among the patients with migraine. The diagnosis of migraine was made clinically based on questionnaires. One hundred and twenty patients with migraine were genotyped for the C276T polymorphism of the nNOS gene and compared with 185 age-matched healthy controls. Genomic DNA from migraine patients and controls was analyzed by polymerase chain reaction (PCR). A PCR-restriction fragment-length polymorphism analysis of nNOS gene polymorphism was performed, and the results were compared. Neither genotype distributions nor the allele frequencies for the C276T polymorphism showed a significant difference between the groups. Additionally, there was no marked differences in genotype distribution or allele frequencies for the migraine without aura and migraine with aura subgroups when compared to control group. These results suggested that migraine of the Turkish population seemed to develop without any alterations in nNOS C276T polymorphism. Our data showed that there is no marked association between the C276T polymorphism of the nNOS gene and migraine.

[Determination of the cytokine gene polymorphism and genetic susceptibility in tuberculosis patients]. / Tüberküloz hastalarinda sitokin gen polimorfizmi ve genetik yatkinligin belirlenmesi.

Tuberculosis (TB) is a complicated disease in which biological, socioeconomical and environmental factors play role. Since only 10% of the individuals infected with Mycobacterium tuberculosis develop active disease, it has been suggested that host genetic factors may influence the risk for the development of TB. In this study, we aimed to investigate the presence and role of single nucleotide polymorphisms in the gene regions responsible for cytokine production, since these factors are considered to be associated with susceptibility or resistance to disease development. Single nucleotide polymorphisms were investigated by Amplification Refractory Mutational System (ARMS) Polymerase Chain Reaction (PCR) and PCR-Restriction Fragment Length Polymorphism (RFLP) methods. The presence of single nucleotide polymorphisms were analyzed in tumor necrosis factor alpha (TNF-α) gene promoter -308 G>A (rs1800629) region, interferon gamma (IFN-γ) gene +874 T>A (rs61923114) region, interleukin (IL)-12B p40 gene 1188 A>C (rs3212227) region, IL-10 gene promoter -1082 G>A (rs1800896) region and IL-4 gene promoter -590 C>T (rs2243250) region. A total of 84 patients (71 male, 13 female; mean age: 32.57 ± 15.94 years) whose clinical samples yielded M.tuberculosis complex growth, and 110 healthy blood donors (93 male, 17 female; mean age: 29.40 ± 11.56 years) as control group were included in this study. Of the patients, 76 (90.5%) were diagnosed as pulmonary and 8 (9.5%) as extrapulmonary TB. While 79 (94.1%) patients were newly diagnosed as TB, 5 (5.9%) patients had a TB history (relapsed TB). It was detected that acid-fast bacilli (AFB) were positive in 58 (69%) patients. According to the single nucleotide polymorphism results, gene frequencies could not be compared for TNF-a gene promoter -308 G>A region since healthy controls were in Hardy-Weinberg equilibrium while the patients were not. There were no statistically significant differences in allele and genotype distribution between the patients and healthy controls in IFN-γ gene +874 T>A region, IL-12B p40 gene 1188 A>C region, IL-10 gene promoter -1082 G>A region and IL-4 gene promoter -590 C>T region (p> 0.05). There were also no statistically significant differences between AFB positive (n= 58) and negative (n= 26) patients, and AFB positive (n= 56) and negative (n= 20) pulmonary TB patients (p> 0.05). In conclusion, no statistically significant differences were found associated with the susceptibility or resistance to TB with single nucleotide polymorphisms in the gene regions responsible for cytokine production in the study population. Only some of the single nucleotide polymorphisms of the gene regions responsible for cytokine release were investigated in our study. Therefore further detailed studies to investigate the polymorphisms in the genes that control the cytokine release and receptors specific for these cytokines, should be conducted. Although this study was performed in a relatively small sized population, these findings might provide a significant contribution to the epidemiologic data about the molecular immunology of TB in Turkey.

FSHR single nucleotide polymorphism frequencies in proven fathers and infertile men in Southeast Turkey.

The influence of FSH receptor (FSHR) variants on male infertility is not completely understood. The present investigation is the first screening study for SNP at nucleotide position -29 in the core promoter region and codon 680 in exon 10 of the FSHR and the effect of the serum levels of FSH on male infertility in Southeast Turkey. The SNPs in codon 680 and at position -29 of the FSHR gene were analyzed by PCR-RFLP technique in 240 men with proven fathers, and 270 infertile men (150 nonobstructive azoospermic and 120 severe oligozoospermic). The separate analysis for SNP at nucleotide position -29 did not show any difference in genotypic frequencies and serum FSH levels. The genotype distribution of SNP at position 680 was different but does not influence serum FSH levels. Together the two SNPs form four discrete haplotypes (A-Thr-Asn, G-Thr-Asn, A-Ala-Ser, and G-Ala-Ser) occurring in 10 combinations. A statistically significant difference in the allelic distribution of G-Asn/G-Ser and G-Ser/G-Ser genotype between proven fathers and infertile men but there were not any statistically significant difference in the overall frequency of the four FSHR haplotypes. We conclude that the FSHR haplotype does not associate with different serum FSH levels but it is differently distributed in proven fathers and infertile men.

Association of (-1,607) 1G/2G polymorphism of matrix metalloproteinase-1 gene with knee osteoarthritis in the Turkish population (knee osteoarthritis and MMPs gene polymorphisms).

The aim of this study was to investigate whether functional polymorphisms in the promoter of matrix metalloproteinase-1 (MMP-1), MMP-2 and MMP-9 genes were associated with susceptibility to knee osteoarthritis in the Turkish population. The MMP-1 -1,607 1G/2G (rs1799750), MMP-2 -1,306 C/T (rs243865), and MMP-9 -1,562 C/T (rs3918242) polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism assay in 157 patients diagnosed with knee osteoarthritis based on the criteria of American College of Rheumatology and in 84 controls in Mersin, Turkey. Genotype distributions and allele frequencies of MMP-1, MMP-2, and MMP-9 gene polymorphisms were compared between the patients and controls. There were significant differences between the groups regarding the genotype distribution of MMP-1 polymorphism (P = 0.001). The frequencies of 1G/1G and 1G/2G genotypes were significantly higher in the knee osteoarthritis than in the controls (P = 0.002, and P = 0.006, respectively). In addition, 1G allele frequency of MMP-1 gene was higher in the patients than in the control group (P = 0.0001). The genotype distributions and allele frequencies of MMP-2 and MMP-9 gene polymorphisms did not differ between the osteoarthritis and the control groups (P > 0.05). These findings suggest that the -1,607 1G/2G polymorphism in the MMP-1 gene may contribute to susceptibility to knee osteoarthritis in the Turkish population.

Lack of association between DRD3 gene polymorphism and response to clozapine in Turkish schizoprenia patients.

It is hypothesized that molecular components of dopaminergic system, especially the dopamine D3 receptor gene (DRD3), may play a crucial role in the pathophysiology of schizophrenia, because it is abundant in the limbic system of the brain and it binds antipsychotic drugs. Several groups attempted to find an association between a serine-to-glycine polymorphism of the DRD3 gene (Ser9Gly) and schizophrenia; however, the results were inconsistent. In this study, we aimed to investigate the relationship of the Serine/Glycine polymorphism of the DRD3 gene with therapeutic response to clozapine treatment between Turkish schizophrenia patients (N = 92) and healthy controls (N = 100). Genotype groups were comparable in BPRS, SAPS, SANS analysis of response to clozapine. Our results suggest that an association between the Ser/Gly polymorphism of DRD3 gene and response to clozapine in Turkish schizophrenia patients is unlikely to exist.

Lack of association polymorphisms of the IL1RN, IL1A, and IL1B genes with knee osteoarthritis in Turkish patients.

PURPOSE: To examine whether polymorphisms of the interleukin 1 receptor antagonist (IL1RN), interleukin 1 alpha (IL1A) and interleukin 1 beta (IL1B) genes are markers of genetic susceptibility to knee osteoarthritis in Turkish patients. METHODS: One hundred and seven patients with knee osteoarthritis and 67 controls were studied. Three polymorphisms of IL1A, IL1B, and IL1RN genes were typed from genomic DNA. Allelic frequencies were compared between patients and control subjects. RESULTS: No significant differences were observed in genotype and allele frequencies of the IL1RN VNTR, IL1A+4845, IL1B+3953 genes polymorphisms between patients and controls. Furthermore, we did not detect any association genotypes of the polymorphisms with the clinical, radiological, and laboratory profiles of patients. CONCLUSIONS: The present study suggest that the IL1RN VNTR, IL1A+4845, IL1B+3953 genes polymorphisms are not genetic markers of susceptibility to knee osteoarthritis in Turkish patients, and are unrelated to the clinical, radiological, and laboratory characteristics of knee osteoarthritis.

Lack of association with TNF-alpha-308 promoter polymorphism in patients with vitiligo.

Vitiligo is an acquired depigmentary disorder of the skin, characterized by incomplete penetrance, multiple susceptibility loci and genetic heterogeneity. An immunologic hypothesis is currently advanced as a possible pathogenesis of vitiligo. The cytokines have an important role in pathogenesis of autoimmunity in which tumor necrosis factor-alpha (TNF-alpha), a paracrine inhibitor of melanocytes, is especially important. Several single-nucleotide polymorphisms (SNP) have been identified in the human TNF gene promoter. The polymorphism at position -308 (TNF-308), which involves substituting G for A and designing the AA genotype, leads to a higher rate of TNF gene transcription than the wild-type GG genotype in in vitro expression studies. It has also been linked to increased susceptibility to several chronic metabolic, degenerative, inflammatory and autoimmune diseases. Therefore, we investigated the TNF-alpha-308 SNP in patients with vitiligo. We examined 61 patients with vitiligo. Healthy age-, ethnically- and sex-matched individuals (n = 123) served as controls. Polymerase chain reaction amplification was used for analysis of the polymorphism at position -308 in promoter of TNF-alpha gene. We found that the distribution of TNF-alpha genotypes in vitiligo patients did not differ from that in control subjects (P > 0.05). Moreover, there was no association between TNF-alpha genotypes and types of vitiligo. In conclusion, we suggest that TNF-alpha-308 SNP is not a genetic risk factor for vitiligo susceptibility.

Association of serotonin transporter gene polymorphism with obstructive sleep apnea syndrome.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnea syndrome (OSAS) is a common condition characterized by repetitive pharyngeal collapse during sleep and daytime sleepiness. There is genetic predisposition to sleep disorders. Serotonin is involved in the regulation of sleep. The synaptic 5-hydroxytryptamine (HT) is inactivated by presynaptic reuptake, which is mediated by the serotonin transporter. Blockage of the serotonin transporter leads to increased extracellular 5-HT. Polymorphism of the serotonin transporter gene (STG) leads to alterations in serotonin level and may be important in OSAS. In this study, we aimed to assess the role of STG polymorphism in OSAS. METHODS: Twenty-seven OSAS patients and 162 healthy volunteers were involved in the study. STG polymorphism was investigated using leukocytes obtained from peripheral blood. RESULTS: There was no difference between the genotypes and allele frequencies of the patients and controls regarding VNTR and HTTLPR polymorphisms (P > .05). The VNTR and HTTLPR variants and the frequencies of 12/12, 12/10, L, and S alleles were not significantly different between male and female control subjects (P > .05). The 12/12 and SS genotypes were over-represented in the female patients, whereas 12/10 and LL genotypes were over-represented in the male patients (P < .05). The genotypes 12 to 12 were over-represented in the male controls, whereas the genotypes 12 to 10 and L/S were over-represented in the male patients (P < .05). The alleles 10 and L were more frequent in the male patients than male controls (P < .05). The genotypes of female patients and female controls were not significantly different (P > .05). The allele 10 and L were less frequent in the female patients than female controls with Fisher's exact testing (P < .05). There was no relation between genotypes and clinical data of the patients (P > .05). CONCLUSION: STG polymorphism appears to be associated with the occurrence of OSAS, especially in male patients. Absence of association of between genetic variants and polysomnography findings may suggest that some mechanisms other than STG polymorphism are involved in OSAS pathophysiology. Our results need confirmation in a larger group of patients with OSAS.

Tardive dyskinesia is not associated with the polymorphisms of 5-HT2A receptor gene, serotonin transporter gene and catechol-o-methyltransferase gene.

BACKGROUND: The pathophysiology of tardive dyskinesia (TD) is not completely understood.Aim. - To assess the relationship of TD with 5-HT2A receptor gene, serotonin transporter gene (5 HTT), and catechol-o-methyltransferase (COMT) gene polymorphisms. METHOD: Our study comprised 111 unrelated subjects who strictly met DSM-IV criteria for schizophrenia and 32 TD, and 79 healthy unrelated controls; all the subjects were of Turkish origin. The analyses of 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were performed using polymerase chain reaction (PCR) technique. RESULTS: The polymorphisms of these genes were not significantly different between the schizophrenic patients, TD and control subjects. CONCLUSION: Our findings indicated that 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were similar in schizophrenia with non-TD, schizophrenia with TD, and healthy controls. These polymorphisms, though, do not help to evaluate the susceptibility to TD.

T102C and -1438 G/A polymorphisms of the 5-HT2A receptor gene in Turkish patients with obsessive-compulsive disorder.

OBJECTIVE: This study aimed to investigate the possible association between T102C and -1438 G/A polymorphism in the 5-HT2A receptor gene and susceptibility to and clinical features of obsessive-compulsive disorder (OCD). METHOD: Fifty-eight patients with OCD and 83 healthy controls were included in the study. All patients were interviewed and rated by Yale-Brown Obsessive-Compulsive Scale. T102C and -1438 G/A polymorphisms of 5-HT2A receptor gene were determined by PCR technique in DNAs of peripheral leucocytes. RESULTS: OCD patients and healthy controls did not show significant differences in genotype distribution for both polymorphisms investigated. We found that frequencies of the TT genotype for T102C polymorphism and the AA genotype for -1438 G/A polymorphism were significantly higher in patients with severe OCD compared to those with moderate or moderate-severe OCD. CONCLUSION: The -1438 G/A and T102C polymorphisms of the 5-HT2A receptor gene are not associated with an increased risk of OCD. Our data suggest that the TT genotype of T102C and the AA genotype of -1438 G/A polymorphism might be a factor in clinical severity of OCD.

DRD4 and DAT1 polymorphisms modulate human gamma band responses.

Gamma oscillations (30-80 Hz) have been demonstrated to be important for perceptual and cognitive processes. Animal and in vitro studies have revealed possible underlying generation mechanisms of the gamma rhythm. However, little is known about the neurochemical modulation of these oscillations during human cognition. Schizophrenia and Attention Deficit Hyperactivity Disorder, which lead to failure of attentional modulation and working memory, introduce significant changes in gamma responses and have significant associations with genetic polymorphisms of dopamine receptor D4 (DRD4), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT). Therefore, the presence of direct relations between these polymorphisms and gamma oscillations was investigated in human subjects using an auditory target detection paradigm. The 7-repeat isoform of the DRD4 polymorphism that produces a subsensitive variant of the D4 receptor enhanced the auditory evoked and induced gamma responses to both standard and target stimuli. The 10/10 genotype of the DAT1 polymorphism, which reduces DAT expression and hence yields an increase in extracellular dopamine, specifically enhanced evoked gamma responses to target stimuli. The COMT polymorphism did not significantly change gamma responses. It seems plausible to assume that the modulation pattern of the evoked gamma response by DRD4 polymorphism relates to reduced inhibition via the D4 receptor, whereas the DAT1 effect is related to the target detection mechanism probably mediated by the D1 receptor.

Association of GABA(B)R1 receptor gene polymorphism with obstructive sleep apnea syndrome.

OBJECTIVE: GABA(B)R (gamma-amino butyric acid B receptor)-mediated neurotransmission has been implicated in the pathophysiology of a variety of neuropsychiatric disorders. GABA(B)R1 gene variants were identified by single-strand conformation analysis. The nucleotide exchanges cause a substitution of alanine to valine in exon 1a1 (Ala20Val), a substitution of glycine to serine in exon 7 (Gly489Ser) and a silent C to G nucleotide exchange encoding the amino acid phenylalanine in exon 11 (Phe658Phe). The significance of GABA(B)R1a gene polymorphism in obstructive sleep apnea syndrome (OSAS) as well as the association of these polymorphisms with the polysomnography findings in OSAS patients are not known. In this study, we aimed to assess the significance of 3 different GABA(B)R1 gene polymorphisms (Ala20Val, Gly489Ser and Phe658Phe) in OSAS. METHODS: Seventy-five patients (23 female and 52 male) with OSAS and 99 healthy volunteers (51 female, 48 male) were included in the study to assess Ala20Val, Gly489Ser and Phe658Phe polymorphisms of the GABA(B)R1 gene. RESULTS: For the Ala20Val variants, there was no significant difference between the genotypes and allele frequencies of the patients and controls, nor between both genders (p > 0.05). For Phe658Phe polymorphism, there was no significant difference between genotypes and allele frequencies of the patients and controls (p > 0.05). However, the C/C genotype was overrepresented and the T/C genotype was less frequent in male than female patients (p = 0.03). The C/C genotype was overrepresented and the T/C genotype was less frequent in male patients than male controls (p = 0.01). For GABA(B)R1-Gly489Ser polymorphism, all of the patients and controls had G/G genotype. The apnea arousal index scores of the male patients with C/C genotype were significantly higher than in the patients with C/T genotype (p = 0.01). The percent total sleep time in non-REM 1 scores of the male patients with T/T genotype were significantly higher than in the patients with T/C genotype (p = 0.021). The percent total sleep time in non-REM 2 scores of the female patients with C/C genotype were significantly higher than in the patients with C/T genotype (p = 0.006). CONCLUSION: The Ala20Val polymorphism of the GABA(B)R1 gene may be associated with OSAS, whereas Gly489Ser polymorphism does not seem to be involved in OSAS. The C/C variant of the Phe658Phe polymorphism GABA(B)R1 gene seems associated with the occurrence of OSAS and is also associated with some sleep related parameters (apnea arousal index and percent total sleep time in non-REM) recorded by polysomnography.

T102C polymorphisms at the 5-HT2A receptor gene in Turkish schizophrenia patients: a possible association with prognosis.

BACKGROUND: Serotonergic system abnormalities have been implicated in the pathogenesis of schizophrenia. The 5-HT2A receptor gene polymorphism has long been implicated to play a role in the pathogenesis of schizophrenia. AIM: In this study, we assessed the relationship of schizophrenia and its subgroups with 5-HT2A receptor gene polymorphism, and attempted to evaluate a possible correlation between the severity and prognosis of the illness and 5-HT2A receptor gene polymorphism. METHOD: Our study comprised 141 unrelated subjects who strictly met DSM-IV criteria for schizophrenia, and 79 healthy unrelated controls, all of Turkish origin. A clinical evaluation of all patients was accomplished applying the Brief Psychiatric Rating Scale (BPRS) test. The analysis of 5-HT2A receptor gene polymorphism was performed using the polymerase chain reaction technique. RESULTS: Regarding 5-HT2A receptor gene polymorphisms, no statistically significant difference was found between schizophrenic patients and control subjects (p > 0.05). There was no significant difference between the average of BPRS points of the patients and 5-HT2A receptor gene polymorphisms (p > 0.05). Although there was no correlation between the duration of illness and polymorphism (p > 0.05), the frequency of hospitalization was found to be higher in the patients with T/C and T/T genotypes compared with the patients with C/C genotype (p < 0.05). CONCLUSION: Our findings indicate that the T102C polymorphisms of the 5-HT2A receptor gene does not play a substantial role in schizophrenia nor help evaluate susceptibility to schizophrenia. Since the 5-HT2A receptor gene polymorphism is associated with the frequency of hospitalization of the patients, it may be an indicator of prognosis in schizophrenia or help differentiate the patients who are somewhat refractory to antipsychotic treatment.

Serotonin transporter gene polymorphism in irritable bowel syndrome.

OBJECTIVES: Serotonin is a key mediator of intestinal peristalsis, and after it is secreted, it is effectively cleansed from the neuronal gap by means of a high affinity substance called serotonin transporter (SERT), which depends on the Na+ and Cl- ions localized in the presynaptic neuronal membranes. The aim of this study was to investigate SERT polymorphism in patients with irritable bowel syndrome (IBS). METHODS: SERT gene polymorphism was assessed by polymerase chain reaction on DNA chains obtained from leukocytes in serum samples from 54 patients diagnosed with IBS and 91 healthy subjects. The polymorphism of two regions (variable number tandem repeats and the SERT gene-linked polymorphic region [5-HTTLPR]) of SERT was assessed. RESULTS: SERT polymorphisms were found to be similar in healthy subjects and IBS patients (p > 0.05). IBS patients were divided into three groups: diarrhea predominant (n = 18), constipation predominant (n = 26), and alternating diarrhea and constipation (n = 10). These groups were compared with respect to gene polymorphism, and it was found that the 5-HTTLPR allele S/S genotype occurred with greater frequency in the constipation predominant group than in the other two subgroups (p < 0.05), and L/S genotype frequency in the diarrhea predominant group was higher than those in the constipation and control groups. CONCLUSIONS: No relationship was found between IBS and SERT gene polymorphism. It is conceivable that the presence of the S/S genotype in IBS patients carries an increased risk of the constipation predominant type of IBS, whereas the presence of the 5-HTTLPR allele L/S genotype carries an increased risk of the diarrhea predominant type.

Lack of association of catechol-O-methyltransferase gene polymorphism in obsessive-compulsive disorder.

The COMT gene has been implicated to be involved in the pathogenesis of obsessive-compulsive disorder (OCD) and various other psychiatric disorders. COMT enzyme activity is governed by a common genetic polymorphism at codon 158 that results in substantial 3- to 4-fold variation in enzymatic activity [a high-activity COMT variant (H) and a low activity variant (L)]. This study evaluates the association between OCD and the COMT gene polymorphism. Fifty-nine OCD patients that were diagnosed according to DSM-IV criteria and 114 healthy control subjects were included in the study. PCR technique was used for molecular analysis. The genotypic pattern of distribution of the COMT gene (H/H, H/L, and L/L genotypes) was not different between the OCD patients and controls. There were no significant differences among the patients with positive family history for OCD, those with negative family history for OCD, and the controls with respect to allele frequencies of the COMT gene polymorphisms. Patients that were homozygous or heterozygous for the L allele had significantly higher insight scores (i.e., poorer insight) on Y-BOCS compared to those homozygous for the H allele. We did not find an association between OCD, family history for OCD, and the COMT gene polymorphism. This study suggests that the COMT gene polymorphism is not directly associated with OCD in our patient group.

Association between the N-acetylation genetic polymorphism and bronchial asthma.

AIMS: Since polymorphic N-acetyltransferase 2 (NAT2) has been suggested as a susceptibility factor for atopic diseases, the study was undertaken to investigate whether an association exists between acetylation polymorphism and asthma patients with atopy. METHODS: The frequencies of NAT2 alleles and genotypes were determined by PCR/RFLP in a total of 210 asthma patients (extrinsic (n = 108) and intrinsic (n = 102) asthmatics) and 240 control subjects. Presence of the NAT2*4 (wild-type) allele defined a NAT2 genotype as rapid and combinations of mutant alleles NAT2*5 A, *5B, *5C, *6 A, and *7B as slow. RESULTS: Genotypes coding for slow acetylation were detected in 70.4, 58.4 and 58.3% of extrinsic asthmatics, but intrinsic asthmatics and control subjects, respectively. The frequency of slow acetylators was higher among extrinsic asthmatics than intrinsic asthmatics, this difference did not reach statistical significance (odds ratio 1.02, 95% confidence interval 0.64, 1.63, P = 0.085). However, we found a relatively moderate, but significantly higher, increased frequency of slow acetylators among extrinsic asthma patients compared with control subjects (odds ratio 1.70, 95% confidence interval 1.04, 2.76, P = 0.042). CONCLUSIONS: This study shows an association between acetylation polymorphism and susceptibility to extrinsic asthma, but not to intrinsic asthma, suggesting a minor role of the NAT2 polymorphism in the development of atopic asthma.