Association Study of Three Gene Polymorphisms Recently Identified by a Genome-Wide Association Study with Obesity-Related Phenotypes in Chinese Children

Associations of genetic variants of lysophosphatidylcholine metabolic enzymes with levels of serum lipids

OBJECTIVE

Metabolic disturbance of lysophosphatidylcholine (LPC) is related with dyslipidemia. Therefore, eight single-nucleotide polymorphisms (SNPs) were selected from LPC metabolic enzymes to study their associations with obesity and serum levels of lipids.

METHODS

A total of 3305 children were recruited from four independent studies. Eight SNPs of LPC metabolic enzymes were selected and genotyped with the matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). The multivariable linear regression model was applied to detect the associations of eight SNPs with obesity-related phenotypes and levels of lipids in each study. Meta-analyses were used to combine the results of four studies.

RESULTS

Only SNP rs4420638 of APOC-1 gene was associated with serum lipids even after Bonferroni correction. The rs4420638 was positively associated with TC (β = 0.15, P = 8.59 × 10^-9) and low-density-lipoprotein-cholesterol (LDL-C, β = 0.16, P = 9.98 × 10^-14) individually.

CONCLUSION

The study firstly revealed the association between APOC-1/rs4420638 and levels of serum lipids in Chinese children, providing evidence for susceptible gene variants of dyslipidemia.

Association of miRNA targetome variants in LAMC1 and GNB3 genes with colorectal cancer and obesity

Background

Colorectal cancer (CRC) is one of the most common obesity‐associated cancers. Inflammation is also considered the most important factor between obesity and CRC. This study aimed to examine miRNAs binding sites variants on inflammatory genes identified using bioinformatics and systematic approach on clinical samples that were collected from CRC patients and controls.

Methods

The candidate variants related to CRC inflammatory genes were obtained from genome‐wide association studies and their population‐specific haplotypes. The variants were analyzed according to their genomic position on the miRNA targetome. Targetome variants in inflammation‐related genes were selected for genetic association study by TaqMan genotyping assay.

Results

The GG genotype of rs7473 decreased the risk of obesity (p < 0.05). Heterozygous genotype (GA) of rs1547715 decreased the risk of CRC (p < 0.05). In the rs7473/rs1547715 genotype and haplotype, the frequencies of AA/GA and GG/AA lessened in CRC and obesity, respectively (p < 0.05).

Conclusions

The variants of rs7473 and rs1547715 were associated with obesity and CRC, respectively. The above‐mentioned associations could be made based on the interactions of these variants with miRNAs.

The current review of adolescent obesity: the role of genetic factors

Obesity, a complex, multi-factor and heterogeneous condition, is thought to result from the interaction of environmental and genetic factors. Considering the result of adolescence obesity in adulthood, the role of genetic factors comes to the fore. Recently, many genome-wide association studies (GWAS) have been conducted and many loci associated with adiposity have been identified. In adolescents, the strongest association with obesity has been found in single nucleotide polymorphisms (SNP) in the FTO gene. Besides FTO, GWAS showed consistent effects between variants in MC4R, TMEM18, TNNI3K, SEC16B, GNPDA2, POMC and obesity. However, these variants may not have similar effects for all ethnic groups. Although recently genetic factors are considered to contribute to obesity, relatively little is known about the specific loci related to obesity and the mechanisms by which they cause obesity.

Genetic variants in the FAM3C gene are associated with lipid traits in Chinese children

BACKGROUND

Previous studies have related FAM3C gene with childhood bone health, and the regulation of lipid metabolism in hepatocytes. The present case-control study aimed to analyze the association of FAM3C genetic variants with overweight/obesity and lipid traits among Chinese children.

METHODS

Two genetic variants (rs7776725 and rs7793554) within the FAM3C gene were genotyped in 3305 Chinese children aged 6-18 years.

RESULTS

In the whole study population, the T-allele of rs7776725 and A-allele of rs7793554 within the FAM3C gene were associated with 40.2% (95% CI: 11.6-76.1%; P = 0.004) and 29.1% (6.9-56.0%; P = 0.008) increased risk of dyslipidemia, higher triglyceride (P = 0.014 and P = 0.001) and lower HDL-C (P = 0.015 and P = 0.003). In addition, we found that rs7776725 interacted with sex on dyslipidemia (P_{for interaction} = 0.004), and sex-stratified analyses showed that it was significantly associated with dyslipidemia only in girls (P = 8.78 × 10^-5). The variant also showed nominally significant interactions with sex on total cholesterol and LDL-C (P_{for interaction} = 0.012 and 0.008).

CONCLUSION

We found that FAM3C genetic variants were associated with dyslipidemia and lipid traits among Chinese children. In addition, we found significant gene-by-sex interactions. Our findings provided evidence supporting the role of FAM3C gene in regulating lipid metabolism in humans.

IMPACT

FAM3C genetic variants were associated with dyslipidemia and lipid traits among Chinese children. In addition, we found significant gene-by-sex interactions. FAM3C/rs7776725 was associated with dyslipidemia and lipid traits only in girls. Our findings provided evidence supporting the role of FAM3C gene in regulating lipid metabolism in humans.

Association of interleukin-6 polymorphisms with obesity: A systematic review and meta-analysis

Obesity is a common metabolic disorder with increasing trend all around the world. Owing to the role of pro-inflammatory cytokines on obesity, we aimed to investigate the role of interleukin-6 (IL-6) polymorphisms on risk of obesity. Electronic literatures were searched in Web of Science, PubMed, Embase, and Scopus. The references of relevant reviews and included studies were also manually checked. All types of observational studies from 1 January 1992 to 28 February 2018 were included. Odds ratio (OR) was estimated by fixed and random effect model. Subgroup analysis was carried out based on age statues. Pooling analysis of eligible studies have been considered for rs2069845 and rs1800796, and no significant results were observed. Minor allele of IL-6 rs1800797polymorphism decreased the risk of obesity/overweight in allelic 0.74 (0.59-0.92), dominant 0.65 (0.49-0.85), and over-dominant 0.66 (0.51-0.87) models. Fourteen eligible studies were included for rs1800795. According to BMI, C allele showed increased risk of obesity in genetic models containing homozygote model 1.47 (1.02-2.12) for body mass index (BMI) ≥ 25 vs. BMI < 25, recessive model 1.32 (1.07-1.63) for BMI ≥ 30 vs. BMI < 25, and homozygote model 1.35 (1.10-1.66) for BMI ≥ 30 vs. BMI < 30. In overall definition of obesity more significant results were observed, including homozygote model in obese vs. normal 1.71 (1.14-2.56). Similarly, subgroups analysis revealed additional significant results. Minor alleles of rs1800795 raised and rs1800797 reduced the risk of obesity, while rs1800796 and rs2069845 may not be associated. However, more observational studies are recommended to confirm these results.

Physical activity attenuates the association between the IRS1 genotype and childhood obesity in Chinese children

BACKGROUND AND AIMS

The insulin receptor substrate 1 (IRS1) rs2943650 was found to be associated with obesity in adults, but the association has not been evaluated in children. The present study aimed to examine whether IRS1 rs2943650 was associated with obesity in Chinese children and investigate the interaction between rs2943650 and physical activity.

METHODS AND RESULTS

IRS1 rs2943650 was genotyped in 3303 Chinese children aged 6-18 years recruited from four independent studies. Logistic regression and linear regression were performed to examine associations. Meta-analyses were conducted to pool the results of the four independent studies. The C-allele carriers of rs2943650 showed a 29% higher risk of obesity than noncarriers (OR (95% CI) = 1.29 (1.05, 1.58), P = 0.02) and a 0.41 kg/m² increase in BMI (β (95% CI) = 0.41 (0.05, 0.78) kg/m², P = 0.02). We also observed significant interactions between rs2943650 and physical activity/sedentary behaviors on obesity (P_{forinteraction}<0.05). Compared with the physically active children (physical activity ≥1 h/d and sedentary behaviors <2 h/d), the risk allele (C) of rs2943650 was significantly associated with a 241% increased risk of obesity among inactive children who participated in physical activity <1 h/d and sedentary behaviors ≥2 h/d (OR (95% CI) = 3.41 (1.45, 8.01), P = 0.005).

CONCLUSIONS

We found that IRS1 rs2943650 was significantly associated with BMI and risk of childhood obesity. Additionally, we also found significant interaction between IRS1 rs2943650 polymorphism and physical activity/sedentary behaviors on childhood obesity. Our study would provide novel insights into the function of the IRS1 gene and the implementation of effective intervention strategies of childhood obesity.