No association of LEPR Gln223Arg polymorphism with leptin, obesity or metabolic disturbances in children

Genetics of Cholesterol-Related Genes in Metabolic Syndrome: A Review of Current Evidence

Metabolic syndrome (MetS) refers to a cluster of metabolic dysregulations, which include insulin resistance, obesity, atherogenic dyslipidemia and hypertension. The complex pathogenesis of MetS encompasses the interplay between environmental and genetic factors. Environmental factors such as excessive nutrients and sedentary lifestyle are modifiable and could be improved by lifestyle modification. However, genetic susceptibility to MetS, a non-modifiable factor, has attracted the attention of researchers, which could act as the basis for future diagnosis, prognosis, and therapy for MetS. Several cholesterol-related genes associated with each characteristic of MetS have been identified, such as apolipoprotein, lipoprotein lipase (LPL), cholesteryl ester transfer protein (CETP) and adiponectin. This review aims to summarize the genetic information of cholesterol-related genes in MetS, which may potentially serve as biomarkers for early prevention and management of MetS.

A study of leptin and its gene 2548 G/A Rs7799039 single-nucleotide polymorphisms in Egyptian children: A single-center experience

BACKGROUND/OBJECTIVES

The pathophysiology of obesity is multifactorial, including genetic and environmental factors. Previous studies had highlighted the association of the leptin gene/receptor with obesity. We aimed to study the leptin gene rs7799039 single nucleotide polymorphism (SNP) in children, and its association with the children's characteristics.

METHODS

A cross-sectional analytic study that included 143 children with obesity (cases) and a comparable group of 86 lean children as controls. The anthropometric measures, blood pressure, and biochemical testing were done for all participants. The real-time polymerase chain reaction was used to detect rs7799039 SNP variant alleles and ELISA for leptin level assessment.

RESULTS

The distribution of rs7799039 SNPs genotypes GG/GA/AA was comparable between both groups. Testing children regardless of their body mass index showed that the abnormalities in blood pressure, lipids values, insulin resistance, and hepatic insulin sensitivity were significantly associated with increased leptin levels. Among cases, the abnormal metabolic status was associated with higher leptin levels.

CONCLUSIONS

The genotype' distribution of leptin gene rs7799039 SNP was similar in both children with obesity and those with normal-weight. The high blood pressure, abnormal lipid profile, and metabolic disturbances, were significantly associated with higher leptin levels and not with leptin gene rs7799039 SNP.

Leptin Levels and Q223R Leptin Receptor Gene Polymorphism in Obese Mexican Young Adults

INTRODUCTION

The Q223R polymorphism of the leptin receptor (LEPR) gene is one of the most common polymorphisms and it is believed to be associated with a damaged capacity of LEPR signaling and with high circulating leptin levels.

METHODS

An observational, cross-sectional, analytical study was carried out in the Autonomous University of Ciudad Juarez, Mexico, where a sample of young adult participants (ranging from 18 to 30 years of age) was obtained. They were classified based on the results of body mass index: non-obese, and overweight/obese. The polymorphic variant was determined by Polymerase Chain Reaction (PCR) from the DNA sample and serum leptin levels were measured by Enzyme-Linked Immuno Sorbent Assay.

RESULTS

A total of 159 participants were included (non-obese, n=103; overweight/obese, n=56). Leptin levels were 15.14±12.3 ng/mL in the non-obese group and 26.13±19.0 ng/mL in the overweight/obese group (p≤0.001). The allelic frequencies of the Q and R alleles of the LEPR gene in the studied subjects were as follows: non-obese, Q=0.56, R=0.44; overweight/obese, Q=0.62, R=0.38. The relative risk for the Q/Q genotype was 1.18 (Cl 0.53-2.34), for Q/R was 1.14 (Cl 0.59-2.18) and for R/R was 0.59 (Cl 0.23-1.50).

CONCLUSIONS

This study shows that leptin levels are associated with overweight/obesity in Mexican young adults, but this is not related to the presence of the Q223R polymorphism in the LEPR gene, so the underlying mechanisms for a possible disturbance in leptin signaling in obese Mexican young adults await further studies.

The Q223R Polymorphism of the Leptin Receptor Gene as a Predictor of Weight Gain in Childhood Obesity and the Identification of Possible Factors Involved

(1) Background: Childhood rapid weight gain during development has been postulated as a predictor of obesity. The objective of this study was to investigate the effect of single nucleotide polymorphisms (SNPs) on the annual weight gain and height growth, as well as identifying possible lifestyle factors involved. (2) Methods: As part of the GENYAL study, 221 children (6–8 years old) of Madrid (Spain) were enrolled. A total of 11 SNPs associated with high childhood body mass indexes (BMIs) were assessed. Anthropometric measurements, dietary and physical activity data, were collected in 2017 and 2018. Bonferroni-corrected linear models were used to fit the data. (3) Results: A significant association between the Q223R LEPR and the weight growth was found, showing a different behavior between GA and GG genotypes (p = 0.001). Regarding lifestyle factors, an interaction between Q223R genotypes and total active weekly hours/week to predict the weight growth (kg/year) was observed (p = 0.023). In all the genotypes, a beneficial effect against rapid weight growth was observed, but the effect size of the interaction was much more significant in homozygous (GG) minor homozygous (β = −0.61 (−0.95, −0.26) versus heterozygous (AG) and wild-type homozygous (AA) genotypes (β = −0.07 (−0.24, 0.09) and β = −0.12 (−0.32, 0.08), respectively). (4) Conclusions: These results may contribute to more personalized recommendations to prevent childhood obesity.

Incendiary Leptin

Leptin is a hormone released by adipose tissue that plays a key role in the control of energy homeostasis through its binding to leptin receptors (LepR), mainly expressed in the hypothalamus. Most scientific evidence points to leptin’s satiating effect being due to its dual capacity to promote the expression of anorexigenic neuropeptides and to reduce orexigenic expression in the hypothalamus. However, it has also been demonstrated that leptin can stimulate (i) thermogenesis in brown adipose tissue (BAT) and (ii) the browning of white adipose tissue (WAT). Since the demonstration of the importance of BAT in humans 10 years ago, its study has aroused great interest, mainly in the improvement of obesity-associated metabolic disorders through the induction of thermogenesis. Consequently, several strategies targeting BAT activation (mainly in rodent models) have demonstrated great potential to improve hyperlipidemias, hepatic steatosis, insulin resistance and weight gain, leading to an overall healthier metabolic profile. Here, we review the potential therapeutic ability of leptin to correct obesity and other metabolic disorders, not only through its satiating effect, but by also utilizing its thermogenic properties.

Food Consumption as a Modifier of the Association between LEPR Gene Variants and Excess Body Weight in Children and Adolescents: A Study of the SCAALA Cohort

No studies showing that food consumption is a modifier of the association of variants of the leptin receptor gene (LEPR) with body weight have involved a Brazilian population. The aim of this study was to evaluate the modifying effect of dietary intake on the association between the LEPR gene and excess weight. In this study, 1211 children and adolescents aged 4⁻11 years were assessed. Participants were genotyped for 112 single-nucleotide variants of the LEPR gene. Anthropometric measurements were performed, and dietary data were obtained. Logistic regressions were used to study the associations of interest. Of the participants, 13.4% were overweight/obese. The risk allele (G) of the rs1137100 variant was associated with excess weight in individuals with fat consumption below the median (odds ratio OR = 1.92; 95% confidence interval CI = 1.18⁻3.14), with daily frequency of consumption of drink/artificial juice (OR = 2.15; 95% CI = 1.26⁻3.68) and refined cereals (OR = 2.17; 95% CI = 1.31⁻3.62) above the median. The risk allele (G) of variant rs1177681 was also associated with excess weight (OR = 2.74; 95% CI = 1.65⁻4.57) in subjects with a daily frequency of refined cereal consumption above the median. The association between LEPR and excess weight can be modulated by the type and distribution of dietary fatty acids, sugary drinks, and refined cereals.

Association between LEPR, FTO, MC4R, and PPARG-2 polymorphisms with obesity traits and metabolic phenotypes in school-aged children

PURPOSE

Evaluate the relationship of leptin receptor (LEPR) rs1137101, fat mass obesity-associated (FTO) receptors 9939609, melanocortin-4 receptors (MC4R) rs2229616 and rs17782313, and proliferator-activated receptor-gamma (PPARG) rs1801282 with clinical and metabolic phenotypes in prepubertal children.

RESEARCH QUESTION

What is the effect of polymorphisms on clinical and metabolic phenotypes in prepubertal children?

METHODS

A cross-sectional descriptive study was performed to evaluate anthropometric features, percentage body fat (%BF), biochemical parameters, and genotype in 773 prepubertal children.

RESULTS

FTO rs9939609 was associated with an increase in body mass index (BMI) and BMI z-score (zBMI). MC4R rs17782313 was associated with a decrease in BMI and +0.06 units in zBMI. LEPR, and PPARG-2 polymorphisms were associated with decreases in BMI and an increase and decrease units in zBMI, respectively. The homozygous SNPs demonstrated increases (FTO rs993609 and MC4R rs17782313) and decreases (LEPR rs1137101, PPARG rs1801282) in zBMI than the homozygous form of the major allele. In the overweight/obese group, the MC4R rs17782313 CC genotype showed higher average weight, zBMI, waist circumference, waist-circumference-to-height ratio, and waist-hip ratio, and lower BMI, mid-upper arm circumference, calf circumference, and %BF (P< 0.05). FTO rs9939609 AT and AA genotypes were associated with lower triglycerides (P < 0.05).

CONCLUSIONS

We showed that MC4R rs17782313 and FTO rs9939609 were positively associated with zBMI, with weak and very weak effects, respectively, suggesting a very scarce contribution to childhood obesity. LEPR rs1137101 and PPARG-2 rs1801282 had weak and medium negative effects on zBMI, respectively, and may slightly protect against childhood obesity.

Leptin Receptor Gene Variant rs11804091 Is Associated with BMI and Insulin Resistance in Spanish Female Obese Children: A Case-Control Study

Leptin is an endocrine hormone that has a critical role in body weight homoeostasis and mediates its effects via the leptin receptor (LEPR). Common polymorphisms in the genes coding leptin receptors have been associated with metabolic abnormalities. We assessed the association of 28 LEPR polymorphisms with body mass index (BMI) and their relationship with obesity-related phenotypes, inflammation and cardiovascular disease risk biomarkers. A multicentre case-control study was conducted in 522 children (286 with obesity and 236 with normal-BMI). All anthropometric, metabolic factors and biomarkers were higher in children with obesity except apolipoprotein (Apo)-AI, cholesterol, high-density lipoprotein cholesterol (HDL-c), and adiponectin, which were lower in the obesity group; and glucose, low-density lipoprotein cholesterol (LDL-c), and matrix metalloproteinase-9 that did not differ between groups. We identified the associations between rs11208659, rs11804091, rs10157275, rs9436303 and rs1627238, and BMI in the whole population, as well as the association of rs11804091, rs10157275, and rs1327118 with BMI in the female group, although only the rs11804091 remained associated after Bonferroni correction (p = 0.038). This single nucleotide polymorphisms (SNP) was also associated with insulin (p = 0.004), homeostasis model assessment for insulin resistance (HOMA-IR) (p = 0.006), quantitative insulin sensitivity check index (QUICKI) (p = 0.005) and adiponectin (p = 0.046) after adjusting for age, Tanner stage and BMI. Our results show a sex-specific association between the rs11804091 and obesity suggesting an influence of this SNP on insulin resistance.

Leptin Receptor Gene Polymorphism and the Risk of Cardiovascular Disease: A Systemic Review and Meta-Analysis

OBJECTIVE

Few studies have assessed the association between leptin receptor (LEPR) gene polymorphism and the risk of cardiovascular disease (CVD). Of the few epidemiological studies on this topic, the results are still controversial.

METHODS

PubMed and Embase were screened for studies from their inception to 9 October 2016. The pooled odds ratio (OR) with the corresponding confidence intervals (CI) were used to measure the effect size for studies that reported the association under allelic, homozygous, and dominant models. Pre-specified characteristics were conducted in the subgroup analysis. Heterogeneity between subgroups was evaluated by meta-regression analysis.

RESULTS

Seven eligible studies involving 44,133 participants were included in our meta-analysis. Borderline significant association was observed between the LEPR gene polymorphism (rs1137101, rs1137100, rs6700896, and rs8179183) and the increased risk of CVD with considerable heterogeneity under the allelic model, and the overall pooled OR (95% CI) was 1.10 (0.99, 1.22). The LEPR gene variant rs6700896, 109G allele, and 109GG genotype were significantly associated with the increased risk of CVD. Furthermore, stratified group analysis revealed that the association was more pronounced for stroke. Race-differences might also cause the considerable heterogeneity and non-significant association.

CONCLUSIONS

This is the first systematic review and meta-analysis to investigate the association between LEPR gene variants and CVD risk. Some LEPR gene variants were significantly associated with the increased risk of CVD. However, the present study is limited in its small number of included studies, considerable heterogeneity, and observational study design. Further research is still warranted to confirm the magnitude of the association.

The FTO rs9939609 and LEPR rs1137101 mothers-newborns gene polymorphisms and maternal fat mass index effects on anthropometric characteristics in newborns: A cross-sectional study on mothers-newborns gene polymorphisms-The FTO-LEPR Study (STROBE-compliant article)

The aim of this study was to assess the impact of mothers' and newborns' fat mass and obesity-associated gene (FTO) rs9939609 and leptin receptor (LEPR) rs1137101 gene polymorphisms on neonatal anthropometric parameters in order to identify a potential risk for developing obesity.We performed a cross-sectional study on 355 mother-newborn couples in an Obstetrics Gynecology Tertiary Hospital from Romania, evaluated with regard to anthropometric parameters, clinical and laboratory parameters besides 2 genetic polymorphisms (FTO rs9939609 and LEPR rs1137101).Newborns with mothers carrying variant AT or AA genotype for FTO rs9939609 presented lower BMI (P = 0.012) and lower MUAC (P = 0.029). There was a significant interaction effect between newborn and mother LEPR rs1137101 polymorphism on birth weight (P = 0.009) and BMI (P = 0.007). We noticed significantly increased birth weight and BMI in newborns carriers of AG + GG genotype, coming from mothers with AA genotype (P = 0.006). There was no evidence of significant interaction effect between newborn and mother FTO rs9939609 polymorphism on the studied anthropometrical data (P > 0.05). In addition, lower BMI scores (P = 0.042) were observed in newborns carriers of TT genotype whose mothers had AA + AT genotype. Lower MUAC scores (P = 0.041) were noticed in newborns carriers of AA + AT genotype whose mothers had AA + AT genotype for FTO rs9939609 gene polymorphism. Newborns carriers of the AG + GG genotype (P = 0.003) of LEPR rs1137101 coming from mothers with increased FMI (upper tertile) had significantly increased BMIs.Presence of the variant A allele of FTO rs9939609 polymorphism in mothers decreased BMI and MUAC in newborns. The impact of LEPR rs1137101 polymorphism on BMI and birth weight in newborns differed depending on the presence/absence of the dominant LEPR allele in mothers. In addition, we noticed that maternal FMI presented a significant positive effect on newborns' BMI by changing the effect of LEPR rs1137101.We can conclude that mothers' FTO rs9939609 and LEPR rs1137101 gene polymorphisms presented an impact on birth weight and newborns' BMI, therefore being involved in the newborns' nutritional status and in the design of a potential protocol.

Correlations Between Leptin Gene Polymorphisms 223 A/G, 1019 G/A, 492 G/C, 976 C/A, and Anthropometrical and Biochemical Parameters in Children With Obesity: A Prospective Case-Control Study in a Romanian Population-The Nutrichild Study

The aim of this study was to establish the manner in which the LEPR 223, 1019, 492, and 976 gene polymorphisms influence child obesity.We performed a prospective case-control study on 264 hospitalized children from Romania (Nutrichild study) whom we divided into 2 groups: Group I -143 controls and Group II-121 obese children.The 2 groups were evaluated regarding the anthropometry (MUAC, TST, H/L, hip, and abdominal circumference), paraclinical results (protein, leptin, adiponectin, TNF alfa, IL 6, IL 8, VEGF, protein, albumin) and LEPR 223, 1019, 492, and 976 gene polymorphisms. We noticed that the most frequent genotypes in obese children were AG+GG for LEPR 223 gene (P = 0.0001) and GA+AA for LEPR 1019 gene (P = 0.0001), whereas LEPR 492 and LEPR 976 gene polymorphisms did not correlate with obesity. MUAC, TST, H/L, leptin, and adiponectin were correlated with the GG genotype of the LEPR 223 gene, whereas the AG genotype correlated with TNF alpha and serum IL 8. Hip and abdominal perimeters were higher in LEPR 1019 AA genotype carriers, whereas TNF alpha and IL 6 correlated with the GG genotype of the same gene. Obesity did not correlate with protein serum levels.We observed that obesity is more frequent in children with LEPR 223 AG+GG and LEPR 1019 GA+AA genotypes. In obese children LEPR 223/492/1019 AG/GG/GA, GG/GG/GA and AA/GG/GA combined genotypes are more frequent.

ADIPOQ -11377C>G Polymorphism Increases the Risk of Adipokine Abnormalities and Child Obesity Regardless of Dietary Intake

OBJECTIVE

The aim of the present study was to verify whether selected functional single nucleotide polymorphisms in LEP, LEPR, and ADIPOQ loci are associated with the development of obesity and serum levels of the respective adipokines in prepubertal white children with obesity.

METHODS

Frequencies of -2548G>A LEP (rs7799039), Q223R (rs1137101) and K656N (rs8129183) LEPR, and -11377C>G (rs266729) and -11426A>G (rs16861194) ADIPOQ polymorphisms were analyzed by restriction fragment length polymorphism in 101 obese (standard deviation score [SDS]-body mass index [BMI] >2) and 67 normal-weight (SDS-BMI <- 1 + 1 >) children. Serum adipokine concentrations were measured using the enzyme-linked immunosorbent assay method.

RESULTS

The GC/GG genotypes of -11377C>G ADIPOQ polymorphism were associated with a higher risk of obesity (P = 0.022, odds ratio 2.08 [95% confidence interval 1.11-3.90]). Individuals carrying the GG genotype had a higher leptin/total adiponectin ratio by 25% than CC homozygotes (P trend = 0.05). In the multivariate linear regression model, we found differences among particular genotypes of this polymorphism in concentrations of high molecular weight (HMW) adiponectin (P trend = 0.043) and HMW/total adiponectin ratio (P trend = 0.048), with the lowest values in GG homozygotes. Positive correlations between SDS-BMI and dietary reference intake percentage were observed in individuals homozygous for allele C (r = 0.403, P = 0.01) and CG heterozygotes (r = 0.428, P = 0.004). No significant correlations between both parameters were found in the GG homozygotes.

CONCLUSIONS

Among the analyzed polymorphisms, only -11377C>G ADIPOQ single nucleotide polymorphism was associated with obesity during the prepubertal period. Adipokine abnormalities coexisting with the lack of relations between SDS-BMI and dietary intake may predict a higher risk of future obesity-related disorders in obese children carrying the GG genotype than in those with other genotypes.

Common variants in LEPR, IL6, AMD1, and NAMPT do not associate with risk of juvenile and childhood obesity in Danes: a case-control study

Background

Childhood obesity is a highly heritable disorder, for which the underlying genetic architecture is largely unknown. Four common variants involved in inflammatory-adipokine triggering (IL6 rs2069845, LEPR rs1137100, NAMPT rs3801266, and AMD1 rs2796749) have recently been associated with obesity and related traits in Indian children. The current study aimed to examine the effect of these variants on risk of childhood/juvenile onset obesity and on obesity-related quantitative traits in two Danish cohorts.

Methods

Genotype information was obtained for 1461 young Caucasian men from the Genetics of Overweight Young Adults (GOYA) study (overweight/obese: 739 and normal weight: 722) and the Danish Childhood Obesity Biobank (TDCOB; overweight/obese: 1022 and normal weight: 650).

Overweight/obesity was defined as having a body mass index (BMI) ≥25 kg/m²; among children and youths, this cut-off was defined using age and sex-specific cut-offs corresponding to an adult body mass index ≥25 kg/m². Risk of obesity was assessed using a logistic regression model whereas obesity-related quantitative measures were analyzed using a general linear model (based on z-scores) stratifying on the case status and adjusting for age and gender. Meta-analyses were performed using the fixed effects model.

Results

No statistically significant association with childhood/juvenile obesity was found for any of the four gene variants among the individual or combined analyses (rs2069845 OR: 0.94 CI: 0.85–1.04; rs1137100 OR: 1.01 CI: 0.90–1.14; rs3801266: 0.96 CI: 0.84–1.10; rs2796749 OR: 1.02 CI: 0.90–1.15; p > 0.05). However, among normal weight children and juvenile men, the LEPR rs1137100 A-allele significantly associated with lower BMI (β = −0.12, p = 0.0026).

Conclusions

The IL6, LEPR, NAMPT, and AMD1 gene variants previously found to associate among Indian children did not associate with risk of obesity or obesity-related quantitative measures among Caucasian children and juvenile men from Denmark.

The Association of Polymorphisms in Leptin/Leptin Receptor Genes and Ghrelin/Ghrelin Receptor Genes With Overweight/Obesity and the Related Metabolic Disturbances: A Review

CONTEXT

Leptin and ghrelin are two important appetite and energy balance-regulating peptides. Common polymorphisms in the genes coding these peptides and their related receptors are shown to be associated with body weight, different markers of obesity and metabolic abnormalities. This review article aims to investigate the association of common polymorphisms of these genes with overweight/obesity and the metabolic disturbances related to it.

EVIDENCE ACQUISITION

The keywords leptin, ghrelin, polymorphism, single-nucleotide polymorphism (SNP), obesity, overweight, Body Mass Index, metabolic syndrome, and type 2 diabetes mellitus (T2DM) (MeSH headings) were used to search in the following databases: Pubmed, Sciencedirect (Elsevier), and Google scholar. Overall, 24 case-control studies, relevant to our topic, met the criteria and were included in the review.

RESULTS

The most prevalent leptin/leptin receptor genes (LEP/LEPR) and ghrelin/ghrelin receptor genes (GHRL/GHSR) single nucleotide polymorphisms studied were LEP G-2548A, LEPR Q223R, and Leu72Met, respectively. Nine studies of the 17 studies on LEP/LEPR, and three studies of the seven studies on GHRL/GHSR showed significant relationships.

CONCLUSIONS

In general, our study suggests that the association between LEP/LEPR and GHRL/GHSR with overweight/obesity and the related metabolic disturbances is inconclusive. These results may be due to unidentified gene-environment interactions. More investigations are needed to further clarify this association.

IGF2, LEPR, POMC, PPARG, and PPARGC1 gene variants are associated with obesity-related risk phenotypes in Brazilian children and adolescents

Association studies of genetic variants and obesity and/or obesity-related risk factors have yielded contradictory results. The aim of the present study was to determine the possible association of five single-nucleotide polymorphisms (SNPs) located in the IGF2, LEPR, POMC, PPARG, and PPARGC1 genes with obesity or obesity-related risk phenotypes. This case-control study assessed overweight (n=192) and normal-weight (n=211) children and adolescents. The SNPs were analyzed using minisequencing assays, and variables and genotype distributions between the groups were compared using one-way analysis of variance and Pearson's chi-square or Fisher's exact tests. Logistic regression analysis adjusted for age and gender was used to calculate the odds ratios (ORs) for selected phenotype risks in each group. No difference in SNP distribution was observed between groups. In children, POMC rs28932472(C) was associated with lower diastolic blood pressure (P=0.001), higher low-density lipoprotein (LDL) cholesterol (P=0.014), and higher risk in overweight children of altered total cholesterol (OR=7.35, P=0.006). In adolescents, IGF2 rs680(A) was associated with higher glucose (P=0.012) and higher risk in overweight adolescents for altered insulin (OR=10.08, P=0.005) and homeostasis model of insulin resistance (HOMA-IR) (OR=6.34, P=0.010). PPARG rs1801282(G) conferred a higher risk of altered insulin (OR=12.31, P=0.003), and HOMA-IR (OR=7.47, P=0.005) in overweight adolescents. PARGC1 rs8192678(A) was associated with higher triacylglycerols (P=0.005), and LEPR rs1137101(A) was marginally associated with higher LDL cholesterol (P=0.017). LEPR rs1137101(A) conferred higher risk for altered insulin, and HOMA-IR in overweight adolescents. The associations observed in this population suggested increased risk for cardiovascular diseases and/or type 2 diabetes later in life for individuals carrying these alleles.

Relationship between leptin receptor and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, which is involved in the multi-system disease, and its etiology is still not clearly understood. It is currently considered that not only the genetic factors but also the environment factors play a crucial role in the pathogenesis of PCOS. Obesity plays an important role through the insulin, leptin and endocannabinoid system in the pathological process of PCOS, leading to more severe clinical manifestations. The aim of our present study is to investigate whether there is association between single nucleotide polymorphisms (SNPs) of Gln223Arg and Pro1019Pro in the leptin receptor gene (LEPR) and PCOS in a Korean population. Interestingly, a significant association was found between the Pro1019Pro in LEPR gene and PCOS, and a highly significant association was found between the Gln223Arg in LEPR gene and PCOS (P=0.033, OR=1.523, 95% confidence interval and P<0.0001, OR=0.446, 95% confidence interval). Moreover, genotype combination and haplotype analyses indicate that Gln223Arg and Pro1019Pro polymorphisms of LEPR are significantly associated with the risk of PCOS.

Impact of leptin receptor gene variants on risk of non-alcoholic fatty liver disease and its interaction with adiponutrin gene

BACKGROUND AND AIM

Genetic polymorphism has been implicated as a factor for the occurrence of non-alcoholic fatty liver disease (NAFLD). This study attempted to assess whether polymorphisms in the leptin receptor (LEPR) gene and its combined effect with patatin-like phospholipase domain-containing protein 3 (PNPLA3/adiponutrin) are associated with risk of NAFLD.

METHODS

A total of 144 biopsy-proven NAFLD and 198 controls were genotyped using the Sequenom MassARRAY platform.

RESULTS

We observed a significant association between the LEPR rs1137100 and rs1137101 with susceptibility to NAFLD (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.18-2.28, P = 0.003; and OR 1.61, 95% CI 1.11-2.34, P = 0.013, respectively) and to non-alcoholic steatohepatitis (OR 1.49, 95% CI 1.05-2.12, P = 0.026; and OR 1.57, 95% CI 1.05-2.35, P = 0.029, respectively). The LEPR rs1137100 is also associated with simple steatosis (OR 2.27, 95% CI 1.27-4.08, P = 0.006). Analysis of gene-gene interaction revealed a strong interaction between the LEPR and PNPLA3 genes (empirical P = 0.001). The joint effect of LEPR and PNPLA3 greatly exacerbated the risk of NAFLD (OR 3.73, 95% CI 1.84-7.55, P < 0.0001). The G allele of rs1137100 is associated with lower fibrosis score (OR 0.47, 95% CI 0.28-0.78, P = 0.001).

CONCLUSIONS

We report an association between variants of LEPR rs1137100 and rs1137101 with risk of NAFLD. This study suggests that rs1137100, specifically the G allele, is associated with a less severe form of liver disease in patients with NAFLD. The interaction between LEPR and PNPLA3 genes showed increased risk of NAFLD compared to either gene alone.

Does Q223R Polymorphism of Leptin Receptor Influence on Anthropometric Parameters and Bone Density in Childhood Cancer Survivors?

Childhood cancer survivors are in augmented risk for developing obesity. For many factors leptin and leptin receptor gene polymorphism play an important role in the development and metabolism not only of fat, but also, bone tissue. The aim of the analysis was to find the relationships between Q223R, leptin levels, and anthropometric parameters. Patients and Methods. In the study 74 cancer survivors participated (ALL n = 64, lymphomas n = 10), and the control group consisted of 51 healthy peers. Leptin blood concentration was determined by ELISA method. To estimate leptin receptor gene polymorphism, RFLP method was used. Bone mineral density (BMD) and content (BMC), fat, and lean tissue measurements were obtained by DXA. Results. We found no correlations between serum leptin concentrations and anthropometric parameters nor BMD. Serum leptin concentrations were significantly lower in the group of cancer survivors compared to controls; however, in those overweight from examined group we found leptin levels higher than those in nonoverweight. Genotype Q223R was not associated with higher leptin levels, BMI, BMD, body fat or lean tissue. Conclusion. To our knowledge, this is the first report describing the relationship between BMD and Q223R polymorphism in childhood cancer survivors. Further analysis, based on a larger group of patients, is needed to confirm these findings.

Aerobic fitness does not modify the effect of FTO variation on body composition traits

PURPOSE

Poor physical fitness and obesity are risk factors for all cause morbidity and mortality. We aimed to clarify whether common genetic variants of key energy intake determinants in leptin (LEP), leptin receptor (LEPR), and fat mass and obesity-associated (FTO) are associated with aerobic and neuromuscular performance, and whether aerobic fitness can alter the effect of these genotypes on body composition.

METHODS

846 healthy Finnish males of Caucasian origin were genotyped for FTO (rs8050136), LEP (rs7799039) and LEPR (rs8179183 and rs1137101) single nucleotide polymorphisms (SNPs), and studied for associations with maximal oxygen consumption, body fat percent, serum leptin levels, waist circumference and maximal force of leg extensor muscles.

RESULTS

Genotype AA of the FTO SNP rs8050136 associated with higher BMI and greater waist circumference compared to the genotype CC. In general linear model, no significant interaction for FTO genotype-relative VO(2)max (mL·kg(-1)·min(-1)) or FTO genotype-absolute VO(2)max (L·min(-1)) on BMI or waist circumference was found. Main effects of aerobic performance on body composition traits were significant (p<0.001). Logistic regression modelling found no significant interaction between aerobic fitness and FTO genotype. LEP SNP rs7799039, LEPR SNPs rs8179183 and rs1137101 did not associate with any of the measured variables, and no significant interactions of LEP or LEPR genotype with aerobic fitness were observed. In addition, none of the studied SNPs associated with aerobic or neuromuscular performance.

CONCLUSIONS

Aerobic fitness may not modify the effect of FTO variation on body composition traits. However, relative aerobic capacity associates with lower BMI and waist circumference regardless of the FTO genotype. FTO, LEP and LEPR genotypes unlikely associate with physical performance.

Genetic polymorphisms in adipokine genes and the risk of obesity: a systematic review and meta-analysis

Polymorphisms in adipokine genes, such as leptin (LEP), leptin receptor (LEPR), resistin (RETN), adiponectin (ADIPOQ), interleukin-1β (IL-1β), IL-6 (IL-6), and tumor necrosis factor-α (TNF-α) may be involved in the development of obesity. We conducted a systematic review of published evidence on the association between different adipokine genes and the risk of obesity. Librarian-designed searches of PubMed and HuGeNet, review of reference lists from published reviews and content expert advice identified potentially eligible studies. The genotyping information and polymorphisms of different adipokine genes, numbers of genotyped cases and controls and frequencies of genotypes were extracted from 48 eligible studies included in this review. Twenty-one polymorphisms each associated with obesity in at least one study were identified. Polymorphisms in the adipokine genes, LEP, LEPR, and RETN were not associated with obesity susceptibility, whereas ADIPOQ G276T (T vs. G: odds ratio (OR), 1.59; 95% confidence interval (CI), 1.39-1.81), IL-1β C3953T (CC vs. CT+TT: OR, 1.61; 95% CI, 1.18-2.20), and TNF-α G308A (GG vs. GA+AA: OR, 1.19; 95% CI, 1.02-1.39) polymorphisms were associated with an increased risk of obesity. The IL-6 G174C polymorphism was also associated obesity when using allelic comparisons, the recessive genetic model and the dominant genetic model with OR (95% CI) of 1.95 (1.37-2.77), 1.44 (1.15-1.80), and 1.36 (1.16-1.59), respectively. No significant evidence of publication bias was present. However, these "null" results were underpowered due to a small pooled sample size, and analysis of additional case-control studies with larger sample sizes should provide further clarifications.

Association between variants of the leptin receptor gene (LEPR) and overweight: a systematic review and an analysis of the CoLaus study

BACKGROUND

Three non-synonymous single nucleotide polymorphisms (Q223R, K109R and K656N) of the leptin receptor gene (LEPR) have been tested for association with obesity-related outcomes in multiple studies, showing inconclusive results. We performed a systematic review and meta-analysis on the association of the three LEPR variants with BMI. In addition, we analysed 15 SNPs within the LEPR gene in the CoLaus study, assessing the interaction of the variants with sex.

METHODOLOGY/PRINCIPAL FINDINGS

We searched electronic databases, including population-based studies that investigated the association between LEPR variants Q223R, K109R and K656N and obesity- related phenotypes in healthy, unrelated subjects. We furthermore performed meta-analyses of the genotype and allele frequencies in case-control studies. Results were stratified by SNP and by potential effect modifiers. CoLaus data were analysed by logistic and linear regressions and tested for interaction with sex. The meta-analysis of published data did not show an overall association between any of the tested LEPR variants and overweight. However, the choice of a BMI cut-off value to distinguish cases from controls was crucial to explain heterogeneity in Q223R. Differences in allele frequencies across ethnic groups are compatible with natural selection of derived alleles in Q223R and K109R and of the ancient allele in K656N in Asians. In CoLaus, the rs10128072, rs3790438 and rs3790437 variants showed interaction with sex for their association with overweight, waist circumference and fat mass in linear regressions.

CONCLUSIONS

Our systematic review and analysis of primary data from the CoLaus study did not show an overall association between LEPR SNPs and overweight. Most studies were underpowered to detect small effect sizes. A potential effect modification by sex, population stratification, as well as the role of natural selection should be addressed in future genetic association studies.