Gln223Arg Polymorphism Research Articles

Leptin receptor Gln223Arg and Lys109Arg polymorphisms may be associated with HBV-related hepatocellular carcinoma risk: A system review and meta-analysis.

Increasing evidence has suggested a strong association of hepatocellular carcinoma (HCC) susceptibility and Gln223Arg (rs1137101) and Lys109Arg (rs1137100) polymorphisms in leptin receptor (LEPR) genes. To provide a quantitative assessment for such correlation, we reviewed all related systems and conducted meta-analysis for case and control researches. A literature search of Web of Science, EMBASE, PubMed, Scopus as well as China National Knowledge Infrastructure databases was collected. 95% confidence intervals (95% CIs) together with odds ratios (ORs) were calculated. Five case-control researches consisting of 1323 cases and 1919 control cases were incorporated into meta-analysis. Researches indicated A-allelic and AA genotype of rs1137101 were substantially related to boosted susceptibility of hepatitis B virus (HBV)-related HCC (mutant model, OR = 1.81, 95% CI = 1.36-2.41, p < .001; allelic model, OR = 1.55, 95% CI = 1.32-1.83, p < .001). On the contrary, we observed GG genotype of rs1137101 substantially related to reduced risk of HBV-related HCC (wild model, OR 0.59, 95%CI = 0.46-0.75, p < .001). We observed AA genotype of rs1137100 relevant to boosted HCC risk (mutant model, OR = 1.51, 95%CI = 1.14-2.01, p = .005) as well as in those with HBV-related HCCs (homozygous model, OR = 2.12, 95%CI = 1.49-3.02, p < .001; mutant model, OR = 1.67, 95%CI = 1.23-2.26, p = .001). G-allele and AA genotype of rs1137101 might be in connection with boosted HBV-related HCC susceptibility, and wild-type GG genotype might prevent diseases. AA genotype of rs1137100 might also improve HBV-related HCC susceptibility. Such conclusions ought to be validated by larger and better-designed researches.

The Arg/Arg genotype of leptin receptor gene Gln223Arg polymorphism may be an independent risk factor for nonalcoholic fatty liver disease.

Given that obesity and insulin resistance play key roles in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and the connection between leptin and these metabolic diseases, the association between NAFLD and a leptin receptor gene (LEPR) polymorphism was examined. In this genetic case-control association study, 144 biopsy-proven NAFLD patients and 144 controls were genotyped for the LEPR gene Gln223Arg (rs1137101) polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. The distributions of genotypes and alleles of Gln223Arg variant were in accordance with the Hardy-Weinberg equilibrium in the study groups (P > .05). Multivariate logistic regression analysis showed that the LEPR Gln223Arg Arg/Arg genotype was an independent risk factor for NAFLD; the Arg/Arg genotype, compared with the Gln/Gln genotype, was associated with a 2.09-fold increased risk for NAFLD (P = .036, odds ratio = 2.09 [95% CI = 1.31-5.95]). We found that the LEPR Gln223Arg Arg/Arg genotype was independently associated with a more than 2-fold rise in biopsy-proven NAFLD risk. Our findings, however, need to be corroborated by further studies.

Leptin Receptor Gln223Arg Polymorphism of Human Spermatozoa Associated with Male Infertility in a Chinese Population.

Leptin (LEP) is believed to play a crucial role in male reproduction, while the molecular mechanisms through which LEP affects the male reproductive system are unclear. LEP acts by binding to a leptin receptor (LEPR) which mediates its physiological action, but there are only limited studies on the function of LEPR in human sperm. This study aimed to determine the Gln223Arg polymorphisms of the LEPR gene in human spermatozoa and evaluate their possible relationship with semen variables. The study was performed on Chinese men: 115 healthy subjects and 108 patients with primary and 98 with secondary infertility. Semen samples were obtained from all patients, and semen variables were analyzed. The genotypic and allelic frequencies of Gln223Arg polymorphism in spermatozoa were determined by PCR and restriction fragment length polymorphism (RFLP) analyses. Statistical analyses were performed using the chi-square test, the Kruskal-Wallis test, and the Mann-Whitney test. There were no significant differences in genotypic or allelic frequency distributions of Gln223Arg polymorphism among men with primary infertility, secondary infertility, and controls. Similarly, semen volume and sperm concentration did not differ with the different genotypes in all groups of men. The percentages of motile sperm for AA + AG genotypes in men with primary infertility (31.98%) were significantly lower than those in secondary infertility, and control men with GG genotypes were 34.41% and 59.36%, respectively. At the same time, the percentages of normal morphology sperm for AA + AG genotypes in men with primary infertility (2.93%) were significantly lower than those in secondary infertility and control men with GG genotypes 3.71% and 6.54%, respectively. This study reveals a possible association between the Gln223Arg polymorphism of the LEPR gene in spermatozoa affecting spermatozoal membrane integrity and having a direct role in sperm motility.

Association of leptin receptor gene Gln223Arg polymorphism with insulin resistance and hyperglycemia in patients with metabolic syndrome.

Worldwide, there has been an increase in the incidence of metabolic syndrome. The search for genetic markers of this syndrome is ongoing. The leptin receptor has recently received attention. One of the polymorphisms (Gln223Arg) is possibly associated with the development of obesity and insulin resistance. However, the results of studies on this polymorphism remain equivocal. Gln223Arg polymorphism has not been studied previously in the Kyrgyz population. Thus, we aimed to investigate the possible association of the Gln223Arg polymorphism of the leptin receptor gene with metabolic syndrome components in the Kyrgyz population. 237 Kyrgyz subjects, aged 35-70 years, were studied. For the analysis anthropometric data, glucose, insulin, lipid spectrum, leptin were obtained. The genotype of the Gln223Arg leptin polymorphism was evaluated using TaqMan real-time PCR. The distribution of genotypes was as follows: Gln223Gln 46.4%, Gln223Arg 40.1%, Arg223Arg 13.5%. In the study no association was found with abdominal obesity, arterial hypertension, hypertriglyceridemia or low-density cholesterol levels. Relationships of Gln223Arg and Arg223Arg genotypes with insulin resistance (p < 0.03) were found. Gln223Arg polymorphism was associated with a higher level of glycemia (5.54 vs. 5.39 mmol/l, p < 0.05) and insulinemia (8.3 vs. 7.1 µIU/ml, p < 0.05). Correlation analysis showed that carriers of the Arg223 allele demonstrated a higher risk of insulin resistance (odds ratio (OR) = 1.83, 95% CI: 1.03-3.24; p < 0.03) than carriers of the Gln223 allele. Gln223Arg polymorphism of the leptin receptor gene may be a marker of predisposition to insulin resistance in the Kyrgyz population. Further studies are necessary to confirm these results in populations from other regions.

Association of the Human Leptin Receptor Gene (rs1137101; Gln223Arg) Polymorphism and Circulating Leptin in Patients with Metabolic Syndrome in the Indian Population.

Phenotypic expression of metabolic syndrome is precipitated by environmental variables along with the individual genetic susceptibility to the obesogenic environment and growing body of evidence suggest a paramount role of adipocytokines. Therefore, identifying the genetic influence on circulation leptin levels and clarifying genotype-phenotype correlation of rs1137101 {Leptin receptor gene (LEPR) Gln223Arg (Q223R; A668G)} in metabolic syndrome were the primary objective of this study. A total of 447 adult participants, including 214 metabolic syndrome patients and 233 healthy controls, were genotyped using polymerase chain reaction-restriction fragment length polymorphism method to unravel the effects of genetic risk loci {Leptin receptor gene; Gln223Arg (Q223R; A668G); rs1137101} on the occurrence of metabolic syndrome in consort with circulation leptin levels. Suitable descriptive statistics was used for different variables. The genotype frequencies were found to be in Hardy-Weinberg equilibrium for both cases (p > 0.2722) as well as in controls (p > 0.2331). However, genotype (x2: 11.26, 2 d.f. p = 0.0036) and allele distribution (x2: 10.51, 2 d.f. p: 0.0012) of the LEPR Gln223Arg (Q223R; A668G) differed significantly between cases and controls. Gln/Arg genotype (OR = 1.6099; 95% CI = 1.0847-2.3893; p value = 0.0181), Arg/Arg genotype (OR = 2.8121; 95% CI = 1.4103-5.6074; p value = 0.0033) and R allele (OR = 1.5875; 95% CI = 1.1996-2.1008; p value = 0.0012) were significantly associated with increased risk of metabolic syndrome in univariate analysis. Further a multivariate logistic regression adjusted for potential confounders showed that Arg/Arg genotype (OR = 1.9; 95% CI = 1.271-2.639; p-value < 0.05) and Gln/Arg (OR: 1.3; 95% CI = 0.873-2.034; p value < 0.05) have a significant risk for the occurrence of the metabolic syndrome. A progressive increase in the serum leptin levels from major homozygous alleles to minor homozygous alleles were observed indicating that rs1137101 modify the serum leptin concentrations in patients with metabolic syndrome. These findings provide enough evidence of a significant association of LEPR Gln223Arg (Q223R; A668G) polymorphism in the LepR gene in Indian patients with increased risk of metabolic syndrome for R allele and Arg/Arg homozygote. Thus, rs1137101 might be a pleiotropic locus for metabolic syndrome and its components in studied population.

Role of Leu72Met of GHRL and Gln223Arg of LEPR Variants on Food Intake, Subjective Appetite, and Hunger-Satiety Hormones.

Appetite regulation has been recognized as a promising target for the prevention of obesity, which has become a worldwide health issue. Polymorphisms in the genes of hormones or receptors including Leu72Met for ghrelin and Gln223Arg for the leptin receptor could play a role in dietary intake, hunger, and satiety process. The aim of this study was to analyze subjective appetite assessments, dietary intake, and appetite hormones in relationship to these polymorphisms. Subjects (n = 132) with normal BMIs were enrolled. Dietary intake was analyzed with 3-day diet records. Subjective appetite was measured by visual analogue scales. Biochemical parameters were measured after 12 h of fasting and 120′ following ingestion of a test meal. Ghrelin and leptin levels were measured by ELISA assay (enzyme-linked immunosorbent assay) and insulin by chemiluminescence assay. The polymorphisms were determined by allelic discrimination using TaqMan® probes. Fasting ghrelin levels differed significantly between men and women. The consumption of fruit and bread/starch with added sugar servings, as indicated by dietary records, and measured ghrelin levels were higher in carriers of Leu72Met/Met72Met compared to Leu72Leu carriers; total sugar intake was higher in Gln223Gln carriers than in Gln223Arg/Arg223Arg carriers. In conclusion, the Leu72Met and Gln223Arg polymorphism in ghrelin and LEPR may contribute to differential responses to a standardized meal as evidenced by higher postprandial levels of ghrelin and may also contribute to a higher dietary sugar intake.

Association of TNF-α 308G/A and LEPR Gln223Arg Polymorphisms with the Risk of Type 2 Diabetes Mellitus.

The objective of the present study was to identify the association of the TNF-α- 308G/A and leptin receptor (LEPR) Gln223Arg polymorphisms with the risk of development of type 2 diabetes mellitus (T2DM). Methods: A total of 160 volunteers were studied: 108 with T2DM and 52 participants as control, who served as the control group. Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) for the genomic region of TNF-α- 308G/A and LEPR Gln223Arg were carried out. Results: The frequency of LEPR Gln223Arg genotypes in T2DM and control groups showed significant differences in the distribution of genotypes (p < 0.05). The frequency also of TNF-α- 308G/A genotypes in T2DM and control subjects showed significant differences in the distribution of genotypes (p < 0.05). Conclusion: Our results indicate that there are significant differences in the distribution of genotypes and alleles between the individuals with T2DM and control subjects (p < 0.05).

The Relationship of Leptin (+19) AG, Leptin (2548) GA, and Leptin Receptor Gln223Arg Gene Polymorphisms with Obesity and Metabolic Syndrome in Obese Children and Adolescents.

PurposeObesity is defined as the abnormal or excessive accumulation of fat over acceptable limits. Leptin is a metabolic hormone present in the circulation in amounts proportional to fat mass. Leptin reduces food intake and increases energy expenditure, thus regulating body weight and homeostasis. Various polymorphisms are present in the leptin gene and its receptor. These polymorphisms may be associated with obesity. This study aimed to show the association of leptin (+19) AG, leptin (2548) GA, and Gln223Arg leptin receptor polymorphisms with obesity and metabolic syndrome in Turkish children aged 6–17 years, and to conduct further investigations regarding the genetic etiology of obesity.MethodsA total of 174 patients diagnosed with obesity and 150 healthy children who were treated at Tokat Gaziosmanpaşa Medical School Hospital between September 2014 and March 2015 were included in this study. The ages of the children were between 6 and 17 years, and anthropometric and laboratory results were recorded. Genotyping of leptin (+19) AG, leptin (2548) GA, and leptin receptor Gln223Arg polymorphisms was performed by polymerase chain reaction.ResultsAn association between leptin receptor Gln223Arg gene polymorphism and obesity was detected.ConclusionFurther studies are needed to determine the role of genetic etiologies and to indicate the role of leptin signal transmission impairment in the pathogenesis of obesity. We hope that gene therapy can soon provide a solution for obesity.

Reduction of Soluble Leptin Receptor Levels in Women with Unexplained Infertility and the Effect of Leptin Receptor Gln223Arg Polymorphism on its Serum Level

Reduction of Soluble Leptin Receptor Levels in Women with Unexplained Infertility and the Effect of Leptin Receptor Gln223Arg Polymorphism on its Serum Level

Is leptin receptor gene (Gln223Arg) polymorphism associated with disease susceptibility and severity in patients of primary knee osteoarthritis?

Aim of the workA significant role of Leptin receptor (LEPR) is documented in inflammation, body weight homeostasis and maintenance of cartilage. This study was conducted to detect the existence of genetic association between Knee osteoarthritis (KOA) susceptibility and severity; and LEPR (Gln223Arg) single nucleotide polymorphism (SNP). Patients and methods73 primary KOA patients and 73 matched healthy controls were studied. Kellgren Laurence (K/L) radiographic grading system, Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and Visual Analogue Scale (VAS) were used to assess the severity of KOA. LEPR Gln223Arg SNP (rs1137101) was genotyped in KOA patients and controls using polymerase chain reaction-restriction fragment length polymorphism (PCR –RFLP) technique and verified by direct DNA sequencing. ResultsIn the current study, a significant genetic association was found between KOA patients carrying the AA genotype of LEPR and the extent of radiological severity (p < 0.044). In addition, a significant difference was detected within the patients between Body Mass Index (BMI) and the SNP. Patients carrying the wild type (GG) genotype showed lower body mass index (BMI) in comparison to patients carrying the heterozygous (AG) genotype and the mutant (AA) genotype (p < 0.032). However, no direct genetic association was detected between the SNP and KOA. ConclusionLeptin receptor gene (Gln223Arg) SNP might be associated with severity of KOA. There is a significant genetic association between the SNP and BMI hence, LEPR SNP might be indirectly associated with the incidence of KOA. Furthermore, the SNP is not directly associated with KOA susceptibility in the Egyptian population.

Variability in the leptin receptor gene and other risk factors for post-transplant diabetes mellitus in renal transplant recipients

Aim Post-transplant diabetes mellitus (PTDM) is one of the main complications after kidney transplantation. It is known that leptin plays an important role in glucose metabolism and mutations in the leptin receptor gene (LEPR) are responsible for different complications in renal transplant recipients. We aimed to analyse the association of polymorphisms in LEPR with the development of PTDM in these patients. Methods A total of 315 renal transplant recipients were genotyped for the Lys109Arg, Gln223Arg and Lys656Asn polymorphisms. The impact of these genetic variables together with other clinical and demographic parameters on PTDM risk was evaluated in a multivariate regression analysis. Results The 223Arg variant showed a significant association with PTDM risk [OR = 3.26 (1.35–7.85), p = 0.009] after correcting for multiple testing. Carriers of this variant also showed higher BMI values (26.95 ± 4.23) than non-carriers (25.67 ± 4.43, p = 0.025). In addition, it was BMI at transplant and not the BMI increment in the first year after grafting that was associated with PTDM (p > 0.00001). Haplotype analyses did not reveal significant associations. Conclusions Our result show, for the first time to our knowledge, that genetic variability in the LEPR may contribute significantly to the risk for PTDM in renal transplant recipients. KEY MESSAGES The LEPR Gln223Arg polymorphism significantly contributes to the development of PTDM in renal transplant recipients. The effect of the 223Arg variant on PTDM is strongly modulated by the age of the recipient. The 223Arg variant in the leptin receptor is related to higher BMI in renal transplant recipients.

Metabolic syndrome in occupational respiratory diseases

Introduction.Metabolic syndrome (MS) is currently considered as aninterdisciplinary medical problem, which is due to its wide prevalence and interrelation with the development of cardiovascular diseases and type 2 diabetes. It is of interest to study the combination of MS and respiratory diseases due to their common pathogenetic mechanisms.Objectiveis to assess an importance of studying MS in patients with occupational respiratory diseases and a possibility of using laboratory parameters as risk markers for developing occupational respiratory diseases and metabolic syndrome combination.Materials and methods.The results of examination of 257 patients with occupational bronchopulmonary pathology were analyzed. Additional tests in patients with occupational asthma (OA) included levels of serum leptin and polymorphisms of inflammatory process regulation genes (interleukins–4, 6, 10, tumor necrosis factor-α, C-reactive protein (CRP), leptin receptor).Study results and discussion.MS was detected in 58.7% of patients with occupational bronchial asthma (OA), in 44.1% of patients with occupational chronic bronchitis, in 48.6% of patients with occupational COPD, and in 38.7% of patients with pneumoconiosis. MS components appeared to be associated with respiratory function parameters. Role of Gln223Arg polymorphisms of leptin receptor gene and C3872T of CRP gene in development of leptin resistance has been confirmed. Findings are that genotype CC (C174G) of IL–6 gene gets 2.5-fold increase of MS development risk (OR=2.507, 95% CI=1.045–6.017), the presence of three or more cytokine gene polymorphisms 2.4 times increases the need to use systemic steroids to control OA (OR=2.449, 95% CI=1.127–5.324).Conclusion.Measures aimed to prevent the development of metabolic disorders in workers exposed to industrial aerosol are at the same time measures to reduce the risk of developing respiratory diseases and to prevent progression of existing diseases. Using informative laboratory markers can optimize treatment and preventive measures, taking into account the individual characteristics of the organism.

Association of LEPRGln223ArgPolymorphism with Obstructive Sleep Apnea Syndrome: A Meta-Analysis.

Previous studies examining the association of leptin receptor (LEPR) Gln223Arg polymorphism with obstructive sleep apnea-hypopnea syndrome (OSAHS) risk have yielded controversial outcomes. We aimed to clarify whether LEPR Gln223Arg polymorphism was critically involved in the development of OSAHS. We thoroughly searched PubMed as well as CNKI datasets for collection of relevant studies, followed by analysis of odds ratios (ORs) with corresponding 95% confidence intervals (CIs). Of the seven case-control studies we enrolled, there was insignificant correlation ofthe LEPR Gln223Arg polymorphism with OSAHSrisk. However, subgroup analysis by Newcastle-Ottawa scale (NOS) scores revealed that, LEPR Gln223Arg polymorphism was significantly related to OSAHS risk in high-quality studies. In addition, we found no publication bias. Our findings suggest that LEPR Gln223Arg polymorphism might contribute to the risk of OSAHS. Well-designed studies with more subjects are needed for further validation of these results.

Relationships between plasma leptin levels, leptin receptor Gln223Arg polymorphism and insulin resistance in Kyrgyz native subjects

Relationships between plasma leptin levels, leptin receptor Gln223Arg polymorphism and insulin resistance in Kyrgyz native subjects

The Relationship between Obstructive Sleep Apnea and Gln223Arg Polymorphism in Human Leptin Receptor Gene

Leptin is derived from an adipocyte and acts through the leptin receptor (LEPR). Gln223Arg polymorphism of the LEPR gene is thought to be associated with impaired signaling capacity of LEPR and with higher mean circulating levels of leptin and obesity; therefore, it may contribute to the pathogenesis of obstructive sleep apnea syndrome (OSAS). The aim of this study was to investigate the frequency of distribution of LEPR gene polymorphism (Gln223Arg) in OSAS patients in relation to polysomnographic traits and phenotype. In total, 230 men (152 OSAS patients and 78 controls) were included in the study. All participants were evaluated by polysomnography in addition to anthropometric, metabolic, and hemodynamic variables. The relationship between these phenotypes and polymorphism of the LEPR gene was investigated by PCR-RFLP. There was no difference between the genotype frequencies of the Gln223Arg polymorphism in the OSAS and control groups. However, OSAS patients carrying the R allele (RR and QR genotypes) had significantly lower Body Mass Index (BMI) than those carrying the Q allele (QQ). OSAS patients with the RR genotype had a significantly lower diastolic blood pressure value than those with the QQ and QR genotypes. When all participants were grouped by blood pressure, the genotype frequency of RR individuals was more prevalent among normotensive men compared to hypertensive men. Gln223Arg polymorphism of LEPR does not seem to be associated with OSAS. This polymorphism may, however, predispose the carrier to reduced BMI and blood pressure. Further studies are needed to unveil the genetic basis of OSAS pathophysiology.

Association of Leptin Receptor Gene Gln223Arg and lys109Arg Polymorphisms with Obesity and Overweight in an Iranian Young Population

Background: Obesity is an energy imbalance disorder that happens due to deficiency of energy intake and consumption. Leptin is an important hormone that regulates energy expenditure. Leptin through its receptors located in the hypothalamus regulates appetite and energy consumption. Objectives: In this study we tried to determine the association of leptin receptor (LEPR) gene polymorphisms (rs1137101), Lys223Arg and Gln109Arg (rs1137100), with overweight and obesity. Methods: We examined the two polymorphisms in 240 subjects consisting of obese, overweight, low-weight, and normal weight (as control) subjects among students of Zanjan Islamic Azad University. For Genotyping, we used PCR-RFLP. Statistical analysis was performed using t-test and chi-square test to show any significant difference between the groups. Results: There was no significant difference in allelic and genotypic frequency of Gln109Arg polymorphism (by A > G substitution) between our study groups. In Lys223Arg polymorphism by A > G substitution, the frequency of AG genotype was higher in the normal group, and the frequency of AA genotype was higher in the obese and overweight groups; but, there was no significant difference in GG genotype and allelic frequency (P < 0.05). Conclusions: In our population, Lys223Arg polymorphism of LEPR gene was associated with obesity; Gln 223 of leptin receptor gene was located in the extra cellular part of receptor and substitution of Glu by Arg in this position might affect leptin signaling. Lys/Arg heterozygote might have protective effects.

LEPR Gene Polymorphism and Plasma Soluble Leptin Receptor Levels are Associated with Polycystic Ovary Syndrome in Han Chinese Women

To investigate the association of LEPR polymorphisms and plasma leptin and soluble leptin receptor (sOB-R) levels with polycystic ovary syndrome (PCOS) in Chinese women. LEPR Lys109Arg (rs1137100) and Gln223Arg (rs1137101) polymorphisms of PCOS patients and the controls were genotyped. Plasma leptin and sOB-R levels of two groups were measured. The genotypic distributions of Lys109Arg (rs1137100) differed between the PCOS and control groups. Plasma sOB-R levels increased significantly in PCOS patients and were associated with PCOS independent of BMI. Furthermore, luteinizing hormone, triglyceride and fasting blood glucose correlated significantly to PCOS patients' sOB-R levels. LEPR Lys109Arg (rs1137100) was associated with PCOS susceptibility and genotype AA was deduced to be a protective factor for PCOS; sOB-R levels might be recognized as a new indicator for the severity of PCOS.

Gln223Arg polymorphism in the Caucasian population and Pro1019Pro polymorphism in the Chinese population are risk factors for OSAS: An updated meta-analysis of 1159 subjects

BackgroundWe conducted a meta-analysis of published literature to identify the correlation between leptin receptor gene polymorphisms and the risk of obstructive sleep apnea syndrome (OSAS). MethodsFive different single nucleotide polymorphisms (SNPs) were studied. Only Gln223Arg and Pro1019Pro had multiple studies. Nine studies focused on the correlation between Gln223Arg and Pro1019Pro polymorphisms and OSAS risk. Fixed-effects model or random-effects model was used to calculate the pooled odds ratio (ORs) and its corresponding 95% confidence interval (95% CI). The Begg's, Egger's, Perter's and Harbord tests were used to measure publication bias. Sensitivity analysis was also performed to ensure the robustness of the findings. ResultsSix studies on Gln223Arg polymorphisms (661 cases and 498 controls) and three studies on Pro1019Pro polymorphisms (561 cases and 561 controls) were extracted. There was no correlation between the leptin receptor Gln223Arg polymorphism and the risk of OSAS (odd ratio=0.86, 95% CI=0.68–1.10, P=0.23). However, Caucasian OSAS patients had a higher Arg allele frequency; whereas Chinese population with G genotype were more susceptible to OSAS (odd ratio=1.28, 95% CI=1.04–1.57, P=0.02) in the studies on Pro1019Pro polymorphisms. ConclusionThe Gln223Arg polymorphisms in the Caucasian population and the Pro1019Pro polymorphisms in the Chinese population are risk factors for OSAS.

Genetic Variation in Leptin Receptor Gene in Diabetic and Non-Diabetic Obese Subjects from Erbil City

There have been numerous genetic causes of obesity specifically leptin, genetic variants of the leptin receptor gene (LEPR Gln223Arg) which appeared to be polymorphismized (A&gt;G; rs1137101) have been implicated in the pathogenesis of obesity in several populations, although no association has been evidenced in other regions in the world. In this study, the association between LEPR Gln223Arg polymorphism with Body Mass Index (BMI) and plasma leptin levels in obese diabetic and obese non-diabetic adults who are randomly selected from Erbil city is evaluated. Blood samples were collected for DNA extraction, and plasma leptin measurements. LEPR (A &gt; G; rs1137101) genotypes were identified by a PCR- RFLP. The results show that plasma leptin concentrations increased with body mass index, and in obese diabetic group was more than two-fold increases p=0.001 when compared to those of obese non-diabetic patients. LEPR (A &gt; G; rs1137101) gene polymorphisms did not found associated with BMI in the whole studied population. Furthermore an increased frequency of the GG genotype in the female control group 32.1 compared to obese group 19.2, but the frequency did not significant (OR= 1.38: 95% CI; 0.74-2.03, P=0.07 ) which indicated that this genotype might be associated with a protective effect against obesity in female only and that this effect was independent of diabetes. Further analysis of a larger population is required to confirm the biological relevance of this polymorphism for obesity in the Kurdish population.

Leptin and leptin-receptor polymorphisms in fertile and infertile men

ABSTRACTThe association of leptin (LEP) -2548G/A and/or leptin receptor (LEPR) Gln223Arg polymorphisms with male infertility and plasma FSH, LH, and testosterone (T) levels was examined. The genotypes and allele frequency distributions of LEP -2548G/A and LEPR Gln223Arg polymorphisms were investigated in 150 fertile and 150 infertile men by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Also, plasma levels of FSH, LH, and T were measured using commercial ELISA kits. Frequencies of AA, AG and GG genotypes of LEP-2548G/A polymorphism were statistically different in fertile and infertile men (p=0.012). The AG genotype showed a protective effect which could decrease risk of male infertility about 3 fold (p = 0.004). We did not observe any differences in frequencies of LEPR Gln223Arg alleles and genotypes between groups (p > 0.05). Sperm counts from infertile men with the AG and GG genotypes of the LEP polymorphism were significantly higher than AA genotype (p<0.05). Moreover, infertile men who carried the RR genotype of LEPR showed a statistically higher percentage of sperm with progressive motility than individuals with other genotypes (p = 0.004). There was no correlation between different combinations of LEP and LEPR genotypes and LH, FSH, and T levels (p > 0.05). Our study suggests that the LEP -2548G/A polymorphism may play a role in male fertility and the AG genotype may have a protective effect through increasing sperm counts. The distribution of genotypes of LEP -2548G/A polymorphism are different in fertile and infertile males and may be a useful tool in evaluation of male infertility.Abbreviations: LEP: leptin; LEPR: leptin receptor; T: testosterone; FSH: follicle-stimulating hormone; LH: luteinizing hormone