Association of leptin/receptor and TNF-α gene variants with adolescent obesity in Malaysia

Association between Leptin (G2548A) and Leptin Receptor (Q223R) Polymorphisms with Plasma Leptin, BMI, Stress, Sleep and Eating Patterns among the Multiethnic Young Malaysian Adult Population from a Healthcare University

Relative leptin resistance in childhood to absolute leptin resistance in maturity suggests sleep, eating behaviour, and the psychological state as probable causes. The current body of research provides inconclusive evidence linking G2548A and Q223R to obesity. Furthermore, we could find very little data that have observed the association between the environment and gene polymorphism, especially in the multiethnic population that exists in Malaysia. This study searched for a possible link between sleeping habits, eating behaviour, and stress indicators with plasma leptin and its genetic variation in young adult Malaysian healthcare students. The study involved 185 first- and second-year medical and dental students from a healthcare university. Polymerase Chain Reaction−Restriction Fragment Length Polymorphism(PCR-RFLP) determined the genotype, Enzyme Linked Immunoabsorbant Assay (ELISA) tested the serum leptin, and a self-administered questionnaire evaluated sleep, eating behaviour, and psychological condition. Gender and ethnicity are linked to fasting plasma leptin levels (p < 0.001). Plasma leptin also affects stress, anxiety, and sadness. Leptin (LEP) and Leptin Receptor (LEPR) polymorphisms were not associated with BMI, plasma leptin, sleep, eating behaviour, or psychological state. Young adult Malaysian Indians were obese and overweight, while Chinese were underweight. These findings imply overweight and obese participants were in stage I of leptin resistance and lifestyle change or leptin therapy could prevent them from becoming cripplingly obese as they age.

Association analysis of genetic variants in the ghrelin and tumor necrosis factor α genes and the risk for non-Hodgkin's lymphoma in Kuwaitis

BACKGROUND:

Non-Hodgkin’s lymphoma (NHL) is the most common hematological malignancy in the world. Many etiologic factors have been implicated in the risk of developing NHL, including genetic susceptibility and obesity. Single-nucleotide polymorphisms (SNPs) in Ghrelin (GHRL), an anti-inflammatory hormone, and tumor necrosis factor α (TNF-α), an inflammatory cytokine, have been independently associated with the risk for obesity and NHL.

OBJECTIVE:

To investigate the association between SNPs in GHRL and TNF-α and the risk for NHL and obesity in Kuwaitis.

METHODS:

We recruited 154 Kuwaiti NHL patients and 217 controls. Genotyping was performed for rs1629816 (GHRL promoter region), rs35684 (GHRL 3’ untranslated region), and rs1800629 (TNF-α promoter region). Logistic regression analysis was performed to assess the association of the investigated SNPs with NHL and the relationship between the selected SNPs with BMI in each group separately.

RESULTS:

We show that rs1629816 GG was associated with an increased risk for NHL in our sample (p= 0.0003, OR 1.82; CI: 1.31–2.54). None of the investigated SNPs were associated with obesity, nor was obesity found to be associated with the risk for NHL.

CONCLUSIONS:

Our study demonstrates an association between rs1629816, a SNP in the GHRL regulatory region, and NHL in Kuwaitis.

Genetic polymorphisms associated with obesity and non-alcoholic fatty liver disease in Asian Indian adolescents

Background The objective of this study was to investigate the association of polymorphisms in four genes, tumor necrosis factor-α (TNFA), patatin-like phospholipase domain containing 3 (PNPLA3), adiponectin (ADIPOQ) and apolipoprotein C3 (APOC3), with obesity and non-alcoholic fatty liver disease (NAFLD) in Asian Indian adolescents. Methods In this case-control study, 218 Asian Indian adolescents with overweight/obesity and 86 lean healthy adults without fatty liver were enrolled. Hepatic steatosis was assessed and graded by ultrasonography (USG). Serum insulin, lipids, alanine aminotransferase (ALT), aspartate aminotransferase (AST), TNF-α, adiponectin and apolipoprotein C3 were measured and genotyping was done. Frequencies of variant and wild genotypes in all adolescents and in the subgroups without steatosis, with grade 1 steatosis and with grade 2 or 3 steatosis were compared to those in the controls. The frequencies were also compared in the overweight adolescents with grade 2 or 3 steatosis and without steatosis. Results Variant genotypes of polymorphisms -863 C > A and -1031 T > C of the TNFA gene, 455 T > C of the APOC3 gene and the wild type of +276 G > T of the ADIPOQ gene were associated with obesity with odds ratios (OR, 95% confidence interval [CI]) of 2.5 (1.5-4.4), 2.5 (1.5-4.2), 2.0 (1.1-3.6) and 2.5 (1.4-5.0), respectively. Polymorphisms 455 T > C of APOC3 and rs738409 C > G of PNPLA3 were associated with NAFLD. Fasting insulin and triglycerides (TG) were higher in the adolescents with homozygous variant polymorphisms -1031 T > C of TNFA and 455 T > C of APOC3 genes, respectively. Conclusions Several polymorphisms were noted to have a significant association with obesity and NAFLD in Asian Indian adolescents.

Molecular dynamic (MD) studies on Gln233Arg (rs1137101) polymorphism of leptin receptor gene and associated variations in the anthropometric and metabolic profiles of Saudi women

The Gln233Arg (A>G; rs1137101) polymorphism of the leptin receptor gene (LEPR) has been investigated extensively and is reported to be associated with different metabolic states. In this investigation, we aimed to study the frequency of Gln233Arg genotypes and alleles in a group of Saudi women stratified by their body mass index (BMI), to correlate the LEPR genotypes with variations in anthropometric, lipid and hormonal parameters and to investigate conformational and structural variations in the mutant LEPR using molecular dynamic (MD) investigations. The study group included 122 Saudi women (normal weight = 60; obese = 62) attending the clinics for a routine checkup. Anthropometric data: height, weight, waist and hip circumference were recorded and fasting serum sample was used to estimate glucose, lipids, ghrelin, leptin and insulin. BMI, W/H ratio, and HOMA-IR values were calculated. Whole blood sample was used to extract DNA; exon 6 of the LEPR gene was amplified by PCR and sequencing was conducted on an ABI 3100 Avant Genetic Analyser. Molecular Dynamic Simulation studies were carried out using different softwares. The results showed the presence of all three genotypes of Gln233Arg in Saudi women, but the frequencies were significantly different when compared to reports from some populations. No differences were seen in the genotype and allele frequencies between the normal weight and obese women. Stratification by the genotypes showed significantly higher BMI, waist and hip circumference, leptin, insulin, fasting glucose and HOMA-IR and lower ghrelin levels in obese women carrying the GG genotype. Even in the normal weight group, individuals with GG genotype had higher BMI, waist and hip circumference and significantly lower ghrelin levels. The MD studies showed a significant effect of the Gln/Arg substitution on the conformation, flexibility, root-mean-square fluctuation (RMSF), radius of gyration (Rg) values, solvent-accessible surface area (SASA) and number of inter- and intra-molecular H-bonds. The results suggest that the structural changes brought about by the mutation, influence the signaling pathways by some unknown mechanism, which may be contributing to the abnormalities seen in the individuals carrying the G allele of rs1137101.

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.

RETRACTED: Association between peroxisome proliferator-activated receptor, UCP3 and lipoprotein lipase gene polymorphisms and obesity in Chinese adolescents

INTRODUCTION

Peroxisome proliferator-activated receptor γ2 (PPARγ2), uncoupling protein gene 3 (UCP3) and lipoprotein lipase (LPL) genes were all related to lipometabolism and obesity. To investigate the association between these three gene polymorphisms and obesity, a case-control study was performed in Shanghai, China.

METHODS

Obese adolescents and normal healthy adolescents aged 12-18 years from Eastern China (Shanghai) were chosen in 2002. The weight, height and body mass index (BMI) of all these adolescents were measured by physical examination. Genotyping for the examined gene polymorphisms were performed by PCR/PCR-RFLP methods. The chi-square test and t-test tests were separately used for the comparison of non-continuous variable and continuous variable, and regression analysis was used for genetic association analyses.

RESULTS

There was only one genotype of CC and no statistical analysis was performed for rs1805192. There was no significant association between rs1800849 gene polymorphism and obesity (TT vs. CC: OR=1.21, 95% CI=0.40-3.62, P=0.734; CT+TT vs. CC: OR=1.11, 95% CI=0.63-1.97, P=0.712; T allele vs. C allele: OR=1.09, 95% CI=0.71-1.68, P=0.698). There was also no significant association between rs328 and obesity (CG vs. CC: OR=0.75, 95% CI=0.36-1.55, P=0.436; CG+GG vs. CC: OR=0.83, 95% CI=0.41-1.69, P=0.604; G allele vs. C allele: OR=0.93, 95% CI=0.48-1.81, P=0.841).

CONCLUSIONS

No significant associations were found between rs1800849 and rs328 gene polymorphisms and obesity in Chinese adolescents.