Association of FTO rs9939609 SNP with Obesity and Obesity- Associated Phenotypes in a North Indian Population

Comparison of the risk of obesity in the FTO rs9939609 genotype in a multiethnic group in Asia systematic review and meta-analysis

Aim

This study aims to examine the comparative risk of obesity in the FTO rs9939609 genotype in multiethnic groups in Asia, considering that obesity has become a global disease.

Data synthesis

Data searches were carried out in several electronic databases: PubMed, Scopus, Google Scholar, ScienceDirect, ClinicalTrials.gov and NCBI. The search involved a combination of keywords related to genetics and obesity risk. Pooled Odds Ratio (POR) with 95% CI was calculated based on the pooled data. Review Manager (RevMan) 5.4.1 were used to analyze the data.

Results

From 18 studies, the results of the dominant genetic model AA vs. TT showed POR 95%Cl = 1.95 (1.36-2.80); p < 0.00001, in AA vs. TA genetic recessive model, POR 95%Cl =1.31 (1.07-1.60); p = 0.002, then the final model of TA vs. TT codominance genetic model obtained POR 95%Cl = 1.52 (1.04-2.23); p < 0.00001. The overall risk of bias was low.

Conclusion

From this research, it was found that there was a comparison of the genotype that had a higher risk of obesity, namely the AA genotype in multiethnic groups in Asia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=546434.

Maximal Fat Oxidation During Exercise in Healthy Individuals: Lack of Genetic Association with the FTO rs9939609 Polymorphism

Background/Objectives: Previous studies suggest that there is a genetically determined component of fat oxidation at rest and during exercise. To date, the FTO gene has been proposed as a candidate gene to affect fat oxidation during exercise because of the association of the "at-risk" A allele with different obesity-related factors such as increased body fat, higher appetite and elevated insulin and triglyceride levels. The A allele of the FTO gene may also be linked to obesity through a reduced capacity for fat oxidation during exercise, a topic that remains largely underexplored in the current literature. The aim of this study was to analyze the association between the FTO rs9939609 polymorphism with the rate of fat oxidation during exercise and metabolic syndrome criteria in healthy participants. Methods: A total of 80 healthy participants (41 men and 39 women) underwent comprehensive assessments, including measurements of anthropometric variables, blood pressure and blood measures of fasting glucose, triglycerides, low- and high-density lipoprotein cholesterol (LDL-c and HDL-c), insulin, interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations. Additionally, the Homeostatic Model Assessment (HOMA-IR) was used to evaluate insulin resistance. Peak oxygen uptake (VO2peak) and maximal fat oxidation rate (MFO) were also measured during an incremental cycling test. FTO rs9939609 genotyping (TT, AT, AA) was performed using genomic DNA samples obtained from a buccal swab and measured with PCR. Results: There were 32 participants (40.0%) with the TT genotype; 31 (38.8%) with the AT genotype; and 17 (21.2%) with the AA genotype. Age, body characteristics, VO2peak, blood pressure and blood variables were similar across all three genotypes. However, serum insulin concentration and HOMA-IR were associated with the FTO rs9939609 genotype with higher values in AA with respect to AT and TT participants (p < 0.050). Still, MFO was similar in TT, AT and AA participants (0.35 ± 0.13, 0.37 ± 0.11, 0.33 ± 0.11 g/min, p = 0.702). In the dominant model, there was no statistical difference between TT and A allele carriers. However, the recessive model revealed that AA participants had higher values of body mass, body mass index, blood insulin concentration and HOMA-IR than T allele carriers (p < 0.050), with no differences in MFO. Conclusions: In our sample of healthy individuals, the FTO rs9939609 polymorphism was associated with several phenotypes associated with obesity and insulin resistance, particularly under the AA vs. T allele/recessive model. However, the FTO rs9939609 polymorphism was not associated with MFO during exercise as fat oxidation was similar across genotypes. This suggests that reduced fat oxidation during exercise is unlikely to be a cause of the obesogenic influence of the FTO AA genotype. Clinically, these findings suggest that the obesogenic effects of the FTO AA genotype are unlikely driven by impaired fat oxidation during exercise. Instead, attention should focus on mechanisms like appetite regulation and energy intake. Moreover, exercise interventions may still effectively mitigate obesity risk, as AA individuals retain normal fat oxidation capacity during exercise.

Association between FTO gene polymorphism and obesity in down syndrome children

Children with Down syndrome (DS) have a higher incidence of overweight and obesity compared to typically developing peers. The fat mass and obesity-associated gene (FTO) is one of the early identified genes linked to obesity in various populations. To date, the FTO rs17817449 gene polymorphism has not been investigated in overweight/obese-DS (ODS) individuals. The current study aimed to explore the potential association between the FTO rs17817449 gene polymorphism and obesity-related markers, and to evaluate the ability of this polymorphism in the prediction of overweight/obesity in DS children and adolescents. This case-control study included 100 DS children under the age of 18, classified into three groups according to BMI-percentile; 50 non-obese DS (NODS), 24 overweight DS, and 26 ODS. Genotyping of FTO gene rs17817449 polymorphism was performed using the restriction fragment length polymorphism (RFLP-PCR) method. Serum lipid and thyroid profiles were also assessed. The results revealed significant increase in the frequency of the FTO rs17817449 T allele among overweight /ODS children compared to NODS children (p=0.0099). Overweight/ODS children exhibited significantly higher frequencies of the FTO rs17817449 GT and TT genotypes compared to NODS children.

CONCLUSION

There is an association between FTO rs17817449 genetic variant and overweight/obesity among the studied DS groups. The FTO rs17817449 GT and TT genotypes, as well as TGs level, were identified as independent risk factors for predicting overweight and obesity in DS children.

WHAT IS KNOWN

• Overweight and obese-DS (ODS) children displayed higher BMI and atherogenic lipid profile than non-obese DS children (NODS). FTO gene polymorphism rs17817449 contributes to obesity development in general population, but there is conflicting information about the risk allele.

WHAT IS NEW

• FTO rs17817449 TT genotype and T allele were considered as independent risk factors for overweight and obesity development in DS children, so they could be used for obesity prediction in DS children.

Association between MCU Gene Polymorphisms with Obesity: Findings from the All of Us Research Program

Obesity is a public health crisis, and its prevalence disproportionately affects African Americans in the United States. Dysregulation of organelle calcium homeostasis is associated with obesity. The mitochondrial calcium uniporter (MCU) complex is primarily responsible for mitochondrial calcium homeostasis. Obesity is a multifactorial disease in which genetic underpinnings such as single-nucleotide polymorphisms (SNPs) may contribute to disease progression. The objective of this study was to identify genetic variations of MCU with anthropometric measurements and obesity in the All of Us Research Program.

METHODS

We used an additive genetic model to assess the association between obesity traits (body mass index (BMI), waist and hip circumference) and selected MCU SNPs in 19,325 participants (3221 normal weight and 16,104 obese). Eleven common MCU SNPs with a minor allele frequency ≥ 5% were used for analysis.

RESULTS

We observed three MCU SNPs in self-reported Black/African American (B/AA) men, and six MCU SNPs in B/AA women associated with increased risk of obesity, whereas six MCU SNPs in White men, and nine MCU SNPs in White women were protective against obesity development.

CONCLUSIONS

This study found associations of MCU SNPs with obesity, providing evidence of a potential predictor of obesity susceptibility in B/AA adults.

Minor alleles in the FTO SNPs contributed to the increased risk of obesity among Korean adults: meta-analysis from nationwide big data-based studies

BACKGROUND/OBJECTIVES

Many studies have revealed an association between fat mass and the obesity-related gene (FTO) and obesity. On the other hand, no meta-analysis was conducted with data from only Koreans. Therefore, this study performed a meta-analysis using Korean data to provide evidence for the association between FTO single nucleotide polymorphisms (SNPs) and the risk of obesity among Korean adults.

SUBJECT/METHODS

Meta-analysis was finally conducted with data extracted from seven datasets of four studies performed on Korean adults after the screening passed. Five kinds of FTO SNPs (rs9939609, rs7193144, rs9940128, rs8050136, and rs9926289) were included, and the relationship between FTO SNPs and body mass index (BMI) was investigated using linear regression with an additive model adjusted for covariants, such as age, sex, and area.

RESULTS

The minor alleles of FTO SNPs were associated with increased BMI (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.21-1.42). In sub-group analysis, FTO rs9939609 T>A was significantly associated with BMI (OR, 1.23; 95% CI, 1.06-1.42). The other FTO SNPs together were significantly associated with BMI (OR, 1.37; 95% CI, 1.25-1.49). The publication bias was not observed based on Egger's test.

CONCLUSIONS

This meta-analysis showed that minor alleles in the FTO SNPs were significantly associated with an increased BMI among Korean adults. This meta-analysis is the first to demonstrate that minor alleles in the FTO SNPs contribute significantly to the increased risk of obesity among Korean adults using data from a Korean population.

Changes in Novel Anthropometric Indices of Abdominal Obesity during Weight Loss with Selected Obesity-Associated Single-Nucleotide Polymorphisms: A Small One-Year Pilot Study

Whether BMI and the competing waist circumference (WC)-based anthropometric indices are associated with obesity-related single-nucleotide polymorphisms (SNPs) is as yet unknown. The current study aimed to evaluate the anthropometric indices (fat mass index, body shape index, visceral adiposity index, relative fat mass, body roundness index, and conicity index) during a weight loss intervention in 36 obese individuals. Blood biochemical parameters (total cholesterol, low-density lipoprotein, high-density lipoprotein, and triglycerides) and three SNPs (FTO rs9939609, TFAP2B rs987237, and PLIN1 rs894160) were assessed in 22 women and 14 men (35.58 ± 9.85 years, BMI 35.04 ± 3.80 kg/m2) who completed a 12-month balanced energy-restricted diet weight loss program. Body composition was assessed via bioelectrical impedance (SECA mBCA515). At the end of the weight loss intervention, all anthropometric indices were significantly reduced (p < 0.05). For the SNP FTO rs9939609, the higher risk allele (A) was characteristic of 88.9% of the study group, in which 10 participants (27.8%) were homozygous. We found a similar distribution of alleles in TFAP2B and PLIN1. Heterozygous genotypes in FTO rs9939609 and TFAP2B rs987237 were predisposed to significant reductions in WC-based novel anthropometric indices during weight loss. The influence of PLIN1 rs894160 polymorphisms on the changes in the analyzed indices during weight loss has not been documented in the present study.

Association of FTO rs9939609 and CD36 rs1761667 with Visceral Obesity

In 2016, more than 1.9 billion adults were overweight; of which, over 650 million of adults were obese. Genetics and lifestyle play important roles in the development of obesity. Studies have shown that genetic variants contribute in developing obesity; such as FTO and CD36, which regulate metabolism and food preferences. Many researches have also emphasized the importance of lifestyle in obesity prevention. However, the interactions of both factors were still underexplored. Therefore, this study was aimed to assess the interaction between FTO-CD36 variants and fat consumption on the metabolic status of healthy Indonesians. Twenty-one females and seventeen males were involved in this cross-sectional study. CD36 rs1761667 and FTO rs9939609 genotypes were identified from blood samples using PCR-RFLP. Data were compared with dietary patterns (24-h food recall), physical activities (IPAQ), medical records, and body compositions (InBody720). Results: CD36 rs1761667 AA and AG group showed higher -but not significant- fat consumption, WHR, and VFA compared to GG. The trend persisted after gender and physical activity adjustment. Meanwhile, FTO rs9939609 AT group showed significant higher WC, WHR and VFA in male subjects after gender and energy balance adjustment: WC (TT: 74.40±3.85, AT: 85.50±5.92, p=0.011), WHR (TT: 0.85±0.02, AT: 0.92±0.04, p=0.010), and VFA (TT: 48.65±10.61, AT: 78.48±15.18, p=0.010). CD36 rs1761667 might be correlated with higher fat consumption and visceral obesity; while FTO rs9939609 showed a significant association with male visceral obesity. These results indicates that both genetic variants were potential as visceral obesity markers.

Genetic factors associated with obesity risks in a Kazakhstani population

Objectives

There is limited published literature on the genetic risks of chronic inflammatory related disease (eg, obesity and cardiovascular disease) among the Central Asia population. The aim is to determine potential genetic loci as risk factors for obesity for the Kazakhstani population.

Setting

Kazakhstan.

Participants

One hundred and sixty-three Kazakhstani nationals (ethnic groups: both Russians and Kazakhs) were recruited for the cross-sectional study. Linear regression models, adjusted for confounding factors, were used to examine the genetic associations of single nucleotide polymorphisms (SNPs) in 19 genetic loci with obesity (73 obese/overweight individuals and 90 controls).

Results

Overall, logistic regression analyses revealed genotypes C/T in CRP (rs1205), A/C in AGTR1 (rs5186), A/G in CBS (rs234706), G/G in FUT2 (rs602662), A/G in PAI-1 (rs1799889), G/T (rs1801131) and A/G (rs1801133) in MTHFR genes significantly decrease risk of overweight/obesity. After stratification for ethnicity, rs234706 was significantly associated with overweight/obesity in both Russians and Kazakhs, while rs1800871 was significant in Kazakhs only.

Conclusions

This study revealed that variations in SNPs known to be associated with cardiovascular health can also contribute to the risks of developing obesity in the population of Kazakhstan.

Fat mass and obesity-associated (FTO) and leptin receptor (LEPR) gene polymorphisms in Egyptian obese subjects

BACKGROUND

Several studies addressed the contribution of fat mass and obesity-associated (FTO) and leptin receptor (LEPR) polymorphisms for the susceptibility to obesity among different ethnic subjects. The main purpose of this work is to evaluate the association of these polymorph\isms with obesity among Egyptian subjects.

SUBJECTS AND METHODS

This case-control study was carried out on 110 unrelated obese Egyptian subjects who were compared with 122 controls. Their genomic DNA was genotyped using the PCR technique.

RESULTS

The allelic frequencies of FTO rs9939609 (A) and LEPR rs1137101 (223R) were significantly higher in obese subjects compared with non-obese controls (p < .001). Comparing different phenotype frequencies including clinical, anthropometric, and biochemical parameters in obese subjects revealed no significant difference in relation to their genotype frequencies (p> .05).

CONCLUSIONS

This study designates a strong association for FTO and LEPR variants with the risk of obesity among Egyptian subjects.

Genetic polymorphisms associated with obesity in the Arab world: a systematic review

BACKGROUND

Obesity, one of the most common chronic health conditions worldwide, is a multifactorial disease caused by complex genetic and environmental interactions. Several association studies have revealed a considerable number of candidate loci for obesity; however, the genotype-phenotype correlations remain unclear. To date, no comprehensive systematic review has been conducted to investigate the genetic risk factors for obesity among Arabs.

OBJECTIVES

This study aimed to systematically review the genetic polymorphisms that are significantly associated with obesity in Arabs.

METHODS

We searched four literature databases (PubMed, Science Direct, Scopus, and Google Scholar) from inception until May 2020 to obtain all reported genetic data related to obesity in Arab populations. Quality assessment and data extraction were performed individually by three investigators.

RESULTS

In total, 59 studies comprising a total of 15,488 cases and 9,760 controls were included in the systematic review. A total of 76 variants located within or near 49 genes were reported to be significantly associated with obesity. Among the 76 variants, two were described as unique to Arabs, as they have not been previously reported in other populations, and 19 were reported to be distinctively associated with obesity in Arabs but not in non-Arab populations.

CONCLUSIONS

There appears to be a unique genetic and clinical susceptibility profile of obesity in Arab patients.

Genetic variants in the fat mass and obesity-associated (FTO) gene confer risk for extreme obesity and modulate adiposity in a Brazilian population

Obesity is a major public health problem worldwide. It has a complex etiology, influenced by environmental and genetic factors. FTO has been recognized as an important genetic factor for obesity development. This study evaluated the contribution of FTO polymorphisms (rs9939609 and rs17817449) for extreme obesity in terms of the period of obesity onset, anthropometric, and biochemical parameters. The haplotype and the combined effects of FTO risk alleles on obesity susceptibility were evaluated. We investigated 169 normal-weight subjects (body mass index, BMI: 22.8 [21.0; 24.0] kg/m²) and 123 extremely obese individuals (BMI: 47.6 [44.1; 53.1] kg/m²). Genotyping was performed by real time PCR. Our results showed a strong association between FTO variants and extreme obesity. Carriers of the AT haplotype had an increased risk for extreme obesity. Gene scores suggested that the risk of developing extreme obesity was increased 1.37-fold per risk allele added. Both polymorphisms also influenced BMI and body weight. Additionally, rs17817449 influenced triglyceride levels. No effect of FTO variants on the period of obesity onset was found. In conclusion, the FTO polymorphisms showed a strong association with development of extreme phenotype of obesity and adiposity modulation in a Brazilian population.

The association of the fat mass and obesity-associated gene (FTO) rs9939609 polymorphism and the severe obesity in a Brazilian population

Background: Obesity occurs due to the interaction between the genetic background and environmental factors, including an increased food intake and a sedentary lifestyle. Nowadays, it is clear that there is a specific circuit, called leptin-melanocortin pathway, which stimulates and suppresses food intake and energy expenditure. Therefore, the aim of this study was to evaluate the influence of genetic variants related to appetite regulation and energy expenditure on severe obesity susceptibility and metabolic phenotypes in a Brazilian cohort. Material and methods: A total of 490 participants were selected (298 severely obese subjects and 192 normal-weight individuals). Genomic DNA was extracted and polymorphisms in protein related to agouti (AGRP; rs5030980), ghrelin (GHRL; rs696217), neuropeptide Y (NPY; rs535870237), melanocortin 4 receptor (MC4R; rs17782313), brain-derived neurotrophic factor (BDNF; rs4074134) and fat mass and obesity-associated (FTO; rs9939609) genes were genotyped using TaqMan® probes. Demographic, anthropometric, biochemical and blood pressure parameters were obtained from the participants. Results: Our results showed that FTO rs9939609 was associated with severe obesity susceptibility. This polymorphism was also related to body weight, body mass index (BMI), waist to weight ratio (WWR) and inverted BMI. Individuals carrying the mutant allele (A) showed higher levels of BMI as well as lower values of WWR and inverted BMI. Conclusion: This study showed that FTO rs9939609 polymorphism plays a significant role in predisposing severe obesity in a Brazilian population.

Evaluation of FTO rs9939609 and MC4R rs17782313 Polymorphisms as Prognostic Biomarkers of Obesity: A Population-based Cross-sectional Study

Objectives

Obesity is a significant risk factor for a number of chronic diseases, including diabetes, cardiovascular diseases, and cancer. Obesity usually results from a combination of causes and contributing factors, including genetics and lifestyle choices. Many studies have shown an association of single nucleotide polymorphisms (SNPs) in the fat mass and obesity-associated (FTO) and the melanocortin-4 receptor (MC4R) genes with body mass index (BMI). Therefore, recognizing the main genes and their relevant genetic variants will aid prediction of obesity risk. The aim of our study was to investigate the frequency of rs9939609 and rs17782313 polymorphisms in FTO and MC4R genes in an Iranian population.

Methods

We enrolled 130 obese patients and 83 healthy weight controls and calculated their BMI. Genomic DNA was extracted from peripheral blood and the frequency of rs9939609 and rs17782313 polymorphisms in FTO and MC4R genes was determined using the tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR).

Results

Significant associations were found between FTO rs9939609 and BMI. Where homozygous risk allele carriers (A-A) have significant higher odds ratio (OR) of being obese than individuals with normal BMI (OR = 6.927, p < 0.005, 95% confidence interval (CI): 3.48–13.78). No significant correlation between MC4R rs17782313 and obesity were observed when compared to healthy weight individuals. Although subjects with C-C genotype had higher odds of obesity (OR = 1.889, p = 0.077, 95%CI: 0.92–3.84).

Conclusions

This study shows a relationship between FTO polymorphism and increased BMI, therefore, SNP in the FTO gene influence changes in BMI and can be considered a prognostic marker of obesity risk.

Genetics of obesity and its measures in India

Obesity is one of the largest global health problems associated with increased morbidity and mortality mediated by its association with several other metabolic disorders. The interaction between the genes and environment plays an important role in the manifestation of obesity. Despite a high heritability (40-70%) of obesity, the search for genetic variants associated with obesity susceptibility has been a challenging task. To date, limited studies have been conducted in India, restricted to the validation of few genetic variants identified by genomewide association studies. In this critical review, we sought to examine the current knowledge of genetic basis of obesity and its measures in the Indian population. A comprehensive literature search was performed using 'PubMed', 'Medline' and 'IndMed' databases to search for citations published until 31st May 2017, using the key terms as 'Genetics' AND 'obesity' AND 'India'. We identified 48 potential studies which fulfilled the eligibility criteria. The findings indicated that FTO, MC4R, TNF-α, PPAR-γ , UCP1, UCP2, LPL, LEPR, AMD1, IL6, APOE, ADIPOQ, DOK5, INSIG2, PBEF1, IL6R, Myostatin, CXCR4, HHEX, IRX3, POMC, NGN3, FOXA2, MTR, TCN and CHDH are some of the important genes studied among the Indian population. Importantly, the role of sexual dimorphism in the genetic regulation of obesity and body fat distribution was also reported in a few studies. Further, seven biological pathways have been identified that contribute to obesity pathogenesis in India. In conclusion, further exploration of pathway-based research on genetics of obesity can be useful for better understanding the pathophysiology of obesity in India.

The Association of a Rare Variant of -93, -53 Promoter Gene Polymorphisms of Lipoprotein Lipase gene with Obesity and Insulin Resistance

OBJECTIVES

Obesity increases the risk of numerous chronic diseases. Obesity is classified clinically using body mass index (BMI), waist-to-hip ratio, and body fat percentage. The lipoprotein lipase (LPL) gene has been linked to lipoprotein metabolism and obesity. We performed a case-control study to determine the association between LPL gene polymorphisms and obesity-associated phenotypes such as insulin resistance (IR).

METHODS

We examined the different LPL gene variants for association in 642 individuals segregated by BMI and IR. Genotyping of the LPL gene -93 and -53 promoter gene polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

A substantial association was observed for -93 gene polymorphism of the LPL gene with obesity, while -53 promoter gene polymorphism showed association with IR.

CONCLUSIONS

We found a significant association between -93 and -53 promoter gene polymorphisms of the LPL gene with obesity and associated phenotypes in the studied population.

Association of fat mass and obesity-associated and retinitis pigmentosa guanosine triphosphatase (GTPase) regulator-interacting protein-1 like polymorphisms with body mass index in Chinese women

Body mass index (BMI) is the most commonly used quantitative measure of adiposity. It is a kind of complex genetic diseases which are caused by multiple susceptibility genes. The first intron of fat mass and obesity-associated (FTO) has been widely discovered to be associated with BMI. Retinitis pigmentosa GTPase regulator-interacting protein-1 like (RPGRIP1L) is located in the upstream region of FTO and has been proved to be linked with obesity through functional tests. We carried out a genetic association analysis to figure out the role of the FTO gene and the RPGRIP1L gene in BMI. A quantitative traits study with 6,102 Chinese female samples, adjusted for age, was performed during our project. Among the twelve SNPs, rs1421085, rs1558902, rs17817449, rs8050136, rs9939609, rs7202296, rs56137030, rs9930506 and rs12149832 in the FTO gene were significantly associated with BMI after Bonferroni correction. Meanwhile, rs9934800 in the RPGRIP1L gene showed significance with BMI before Bonferroni correction, but this association was eliminated after Bonferroni correction. Our results suggested that genetic variants in the FTO gene were strongly associated with BMI in Chinese women, which may serve as targets of pharmaceutical research and development concerning BMI. Meanwhile, we didn't found the significant association between RPGRIP1L and BMI in Chinese women.

Establishing a genetic link between FTO and VDR gene polymorphisms and obesity in the Emirati population

Background

Obesity is a metabolic disease that is widely prevalent with approximately 600 million people classified as obese worldwide. Its etiology is multifactorial and involves a complex interplay between genes and the environment. Over the past few decades, obesity rates among the Emirati population have been increasing. The aim of this study was to investigate the association of candidate gene single nucleotide polymorphisms (SNPs), namely FTO (rs9939609) and VDR (rs1544410), with obesity in the UAE population.

Methods

This is a case-control study in which genomic DNA was extracted from saliva samples of 201 obese, 115 overweight, and 98 normal subjects in the United Arab Emirates (UAE). Genotyping for the variants was performed using TaqMan assay.

Results

The mean Body Mass Index (BMI) ± SD for the obese, overweight, and normal subjects was 35.76 ± 4.54, 27.53 ± 1.45, and 22.69 ± 1.84 kg/m², respectively. Increasing BMI values were associated with increase in values of HbA1c, systolic and diastolic blood pressure. There was a significant association observed between the FTO SNP rs9939609 and BMI (p = 0.028), with the minor allele A having a clear additive effect on BMI values. There was no significant association detected between BMI and rs1544410 of VDR. Moreover, significant interaction between the FTO rs9939609 and physical activity reduced the “AA” genotype effect on increase in BMI (p = 0.027).

Conclusions

Our study findings indicate that the minor allele A of the rs9939609 has a significant association with increasing BMI values. Moreover, our findings support the fact that increasing BMI is associated with increasing risks of other comorbidities such as higher blood pressure, poorer glycemic control, and higher triglycerides. In addition, physical activity was found to attenuate the effect of the “AA” genotype on the predisposition to higher BMI values.

New Insights Regarding Genetic Aspects of Childhood Obesity: A Minireview

Introduction: Childhood obesity is occurring at alarming rates in both developed and developing countries. "Obesogenic" environmental factors must be associated with variants of different risk alleles to determine polygenic or common obesity, and their impact depends on different developmental stages.The interaction between obesogenic environment and genetic susceptibility results in the so-called polygenic forms of obesity. In contrast, monogenic and syndromic obesity are not influenced by environmental events. Therefore, this review aimed to underline the roles of some of the most studied genes in the development of monogenic and polygenic obesity in children. Results: Among the most common obesity related genes, we chose the fat mass and obesity-associated (FTO) gene, leptin gene and its receptor, tumor necrosis factor alpha (TNF-α), the melanocortin 4 receptor gene (MC4R), Ectoenzyme nucleotide pyrophosphate phosphodiesterase 1 (ENPP1), and others, such as peroxisome proliferator-activated receptor gamma (PPARG), angiotensin-converting enzyme (ACE), glutathione S-transferase (GST), and interleukin-6 (IL-6) genes. The roles of these genes are complex and interdependent, being linked to different cornerstones in obesity development, such as appetite behavior, control of food intake and energy balance, insulin signaling, lipid and glucose metabolism, metabolic disorders, adipocyte differentiation, and so on. Conclusions: Genetic predisposition is mandatory, but not enough to trigger obesity.Dietary interventions and proper lifestyle changes can prevent obesity development in genetically predisposed children. Further studies are needed to identify the precise role of both genetic and obesogenic factors in the development of childhood obesity in order to design effective preventive methods.

FTO rs9939609 Does Not Interact with Physical Exercise but Influences Basal Insulin Metabolism in Brazilian Overweight and Obese Adolescents

PURPOSE

The rs9939609 SNP (T > A) in FTO gene is associated with obesity and type 2 diabetes. The present study aimed at verifying whether this SNP influenced biochemical outcomes of children and adolescents who are overweight/obese submitted to a program of physical exercise and also if there was influence on basal levels of these biochemical variables.

METHODS

The sample was composed by 432 children and adolescents grouped in three ways (obese, overweight, and normal weight); of these, 135 children and adoloescents who are obese and overweight were submitted to a physical exercise program for 12 weeks. All were genotyped by TaqMan SNP genotyping assay.

RESULTS

The children and adolescents who are overweight/obese and carriers of AA genotype had higher levels of insulin (p=0.03) and HOMA (p=0.007) and lower levels of glucose (p=0.003), but the SNP did not modulate the response to physical exercise.

CONCLUSIONS

In our study, the rs9939609 AA genotype was associated with parameters related to insulin metabolism but did not interact with physical exercise.

FTO rs9939609 A allele influences anthropometric outcome in response to dietary intervention, but not in response to physical exercise program

PURPOSE

The fat mass and obesity-associated (FTO) gene is involved in energy homeostasis. The A allele of the rs9939609 (SNP; T>A) is associated with obesity and higher food intake, while its effect in energy expenditure remains unclear. The aim of this study is to examine whether FTO rs9939609 is associated with the anthropometric outcomes of a physical exercise program and a dietary intervention.

METHODS

We studied two independent samples. The first was composed by children and adolescents in which overweight and obese individuals were submitted to a physical exercise program (n = 136) and normal weight participants served as a control group (n = 172). The second sample was composed by obese women submitted to a hypocaloric dietary intervention (n = 126).

RESULTS

Physical exercise and dietary intervention were effective, independently of genotype. We found no association of FTO rs9939609 with obesity in children and adolescents (p = 0.67). The rs9939609 affected the response to dietary intervention in obese women: A allele carriers reduced 2.7 cm less of abdominal circumference (AC) than homozygous TT (p = 0.04), while no effect was observed in response to physical exercise in overweight and obese children and adolescents.

CONCLUSIONS

The A allele is associated with a worse outcome in response to the hypocaloric dietary intervention regarding abdominal circumference reduction; the same allele did not show interaction with any anthropometric outcomes in response to the exercise program applied.