The aim of this study is to investigate whether the genetic risk score (GRS) based on previously associated obesity polymorphisms (SNP) rs9939609 (fat mass and obesity-associated (FTO)), rs6548238 (transmembrane protein 18 (TMEM18)) and rs16835198 (fibronectin type III domain containing 5 (FNDC5)) could serve as a predictor for anthropometric characteristics in a sample of Brazilian children and adolescents.
Transmembrane protein 18 (Tmem18) is an obesity-associated gene essential for adipogenesis; however, its function in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) is still unclear.
Single SNP analysis showed that genetic variants in SLC30A10, TMEM18, GNPDA2, PRL, TFAP2B, BDNF, MTCH2, FTO, and MC4R were nominally associated with waist circumference (WC), BMI, and risk for abdominal or general obesity in the untreated patients with type 2 diabetes, as well as in the total group of patients with type 2 diabetes (untreated and treated) (p < 0.05).
BACKGROUND This study was carried out to determine the relationship between the common TMEM-18 (rs4854344, G>T) and NYD-SP18 (rs6971091, G>A) gene variants and weight loss after lifestyle interventions (increased physical activity in conjunction with optimal dietary intake) in overweight/obese children/adolescents.
The observed association between variants in/near FTO, MC4R, MTCH2, TFAP2B, SEC16B and TMEM18 with change in BMI from adolescence to young adulthood suggest that the genetic effect of BMI loci varies over time in a complex manner, highlighting the importance of investigating loci influencing obesity risk across the life course.
In this multi-analytical approach, FTO rs9939609 and IRX3 rs3751723, along with TCF7L2 rs7903146 and TMEM18rs6548238, emerged as the major SNPs contributing to BMI linked obesity risk in the North Indian population.
In addition, we confirmed three previously reported obesity susceptibility loci: 16q12 [rs62033400, P = 1.97 × 10(-14), FTO (fat mass and obesity associated)], 18q22 [rs6567160, P = 8.09 × 10(-19), MC4R (melanocortin 4 receptor)] and 2p25 [rs939583, P = 1.07 × 10(-7), TMEM18 (transmembrane protein 18)].
This study aims to test whether 10 polymorphisms in obesity-related genes methionine sulfoxide reductase A (MSRA), transcription factor AP-2 beta (TFAP2B), melanocortin 4 receptor (MC4R), neurexin 3 (NRXN3), peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A), transmembrane protein 18 (TMEM18), homolog of S. cerevisiae Sec16 (SEC16B), homeobox B5 (HOXB5) and olfactomedin 4 (OLFM4) are associated with the risk of obesity in Portuguese children.
In the meta-analysis of 42 studies for 11 obesity/BMI-associated loci, we observed a statistically significant association of the FTO rs9939609 polymorphism (66 425 T2D cases/239 689 normoglycaemic subjects; P = 1·00 × 10(-41) ) and six other variants with T2D risk (17 915 T2D cases/27 531 normoglycaemic individuals: n = 40 629-130 001; all P < 0·001 for SH2B1 rs7498665, FAIM2 rs7138803, TMEM18rs7561317, GNPDA2 rs10938397, BDNF rs925946 and NEGR1 rs2568958).
We genotyped obesity risk single nucleotide polymorphisms (SNPs) derived from genome-wide association studies in or in proximity to the following genes: NEGR1, TNKS, SDCCAG8, FTO, MC4R, TMEM18, PTER, MTCH2, SH2B1, MAF, NPC1, and KCTD15.
Eight loci, rs10968576 (BDNF), rs3817334 (MTCH2), rs1558902 (FTO), rs571312 (MC4R), rs543874 (SEC16B), rs987237 (TFAP2B), rs2867125 (TMEM18) and rs7138803 (FAIM2), were previously known obesity susceptibility loci, and the remaining four loci, rs1514175 (TNNI3K), rs206936 (NUDT3), rs4771122 (MTIF3) and rs2241423 (MAP2K5), were newly identified as BMI loci by the GIANT study.
We tested the hypothesis that the ADRB2rs1800888(Thr164Ile) polymorphism associates with risk of obesity and diabetes and compared effect sizes with those of FTO(rs9939609), MC4R(rs17782313), and TMEM18(rs6548238).
Variants of TMEM18 and FTO are associated with obesity indices during puberty in Chinese children, but candidate SNPs of NEGR1, GNPDA2, MTCH2, SH2B1, MC4R and KCTD15 have no significant effects on obesity indices.
There is evidence that obesity and obesity-related phenotypes are associated with variations in several genes, including NEGR1, SEC16B, TMEM18, ETV5, GNPDA2, BDNF, MTCH2, SH2B1, FTO, MAF, MC4R, KCTD15, SCG3, MTMR9, TFAP2B, MSRA, LYPLAL1, GCKR and FADS1.
These data support the original finding that there is an association between measures of obesity and a variant near the MC4R gene and extends these results to a younger population and implicates FTO, TMEM18, and SH2B1 polymorphisms in subcutaneous fat regulation.