Interactions of anthropometric indices,rs9939609 FTO gene polymorphism and breast cancer: A case-control study

Contradictory results were reported on the effect of fat mass- and obesity-associated (FTO) gene and anthropometric measurements on breast cancer (BC). This study aimed to assess the interactions between rs9939609 polymorphism of FTO gene, anthropometric indices and BC risk in Iranian women. This case-control study was performed on 540 women including 180 women with BC and 360 healthy women in Tehran, Iran. Physical activity and dietary intakes were assessed by validated questionnaires. Data on sociodemographic and pathologic factors of the participants as well as their blood samples were collected. The rs9939609 FTO gene polymorphism was genotyped using the tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR). No significant association was found between BC and risk allele of FTO rs9939609 polymorphism after adjustments for the confounders. However, there was a significant association between rs9939609 polymorphism risk allele and BC risk in females with overweight, even after adjusting for age, family history of BC, abortion, BMI and the number of pregnancies (P < .05). The association was disappeared after further adjustments for lifestyle factors including smoking, alcohol consumption, calorie and macronutrients intake, and physical activity. The FTO gene polymorphism was associated with the risk of BC in overweight individuals. This association was influenced by environmental factors including diet, alcohol consumption and smoking. Future studies are required to confirm the association between the FTO gene and BC in overweight females and to identify the underlying mechanisms.     

FTO at rs9939609, Food Responsiveness,Emotional Control and Symptoms of ADHD in Preschool Children

The FTO minor allele at rs9939609 has been associated with body mass index (BMI: weight (kg)/height (m)²) in children from 5 years onwards, food intake, and eating behaviour. The high expression of FTO in the brain suggests that this gene may also be associated with behavioural phenotypes, such as impulsivity and control. We examined the effect of the FTO minor allele (A) at rs9939609 on eating behaviour, impulsivity and control in young children, thus before the BMI effect becomes apparent. This study was embedded in the Generation R Study, a population-based cohort from fetal life onwards. 1,718 children of European descent were genotyped for FTO at rs9939609. With logistic regression assuming an additive genetic model, we examined the association between the FTO minor allele and eating behaviour, impulsivity and control in preschool children. There was no relation between FTO at rs9939609 and child BMI at this age. The A allele at rs9939609 was associated with increased food responsiveness (OR 1.21, p = 0.03). Also, children with the A allele were less likely to have symptoms of ADHD (OR 0.74, p = 0.01) and showed more emotional control (OR 0.64, p = 0.01) compared to children without the A allele. Our findings suggest that before the association between FTO and BMI becomes apparent, the FTO minor allele at rs9939609 leads to increased food responsiveness, a decreased risk for symptoms of ADHD and better emotional control. Future studies are needed to investigate whether these findings represent one single mechanism or reflect pleiotropic effects of FTO.     

Inverse Association between Obesity Predisposing FTO Genotype and Completed Suicide

The A allele of rs9939609 in the FTO gene predisposes to increased body mass index (BMI) and obesity. Recently we showed an inverse association between the obesity related A allele of rs9939609 and alcohol dependence which was replicated by others. Since this finding raises a possibility that FTO may be associated with other psychiatric phenotypes, we aimed to examine association of rs9939609 with completed suicide. We genotyped rs9939609 in 912 suicide victims and 733 controls using TaqMan approach. We observed an inverse association between suicide and the rs9939609 A allele (OR = 0.80, P = 0.002, P_cor = 0.006) with genotype distribution suggesting a co-dominant effect. Given the link between alcoholism and suicide under influence of alcohol reported in Polish population, confounding by alcohol addiction was unlikely due to apparently similar effect size among cases who were under influence of ethanol at the time of death (OR = 0.76, P = 0.003, N = 361) and those who were not (OR = 0.80, P = 0.007, N = 469). The search for genotype-phenotype correlations did not show significant results. In conclusion, our study proves that there is an inverse association between rs9939609 polymorphism in FTO gene and completed suicide which is independent from association between FTO and alcohol addiction.     

Asociación de polimorfismos en el gen FTO con la obesidad mórbida en la población extremeña

ObjectiveTo select individuals whose morbid obesity can be attributed mainly to their individual genetic profile. After excluding patients with potential monogenic syndromes or diseases associated with obesity, we evaluated the association of the single nucleotide polymorphisms (SNPs) rs1861868 and rs9939609 of the fat-mass and obesity-associated FTO gene with an inherited predisposition to morbid obesity.Patients and methodsWe evaluated 270 patients with morbid obesity and onset before the age of 14 years and selected 194 due to their phenotypes and family history; 289 control individuals were included. The rs1861868 and rs9939609 variants, located in the FTO gene, were genotyped. Genotype and haplotype frequencies were compared between cases and controls.ResultsThe A allele of rs9939609 was associated with severe obesity starting in childhood among the Spanish population. The rs1861868 G/rs9939609 A haplotype of the FTO gene was also significantly associated with severe obesity in our population, with an odds ratio of 3.03 (95% confidence interval, 1.74–5.27).ConclusionAnalysis of the genetic basis of obesity requires rigorous selection of cases. In this study, the association of the rs9939609 SNP with obesity widely described in distinct populations was confirmed among overweight Spanish children. Genotyping rs1861868 allowed us to identify the first risk haplotype in the FTO gene, which is located in the adjacent haplotype block containing rs9939609. In-depth study of the variability of the FTO gene is essential to define its deleterious capacity.     

Interaction between obesity-related genes, FTO and MC4R, associated to an increase of breast cancer risk

Breast cancer (BC) is a complex disease and obesity is a well-known risk factor for its development, especially after menopause. Several studies have shown Single Nucleotide Polymorphisms (SNPs) linked to overweight and obesity, such as: rs1121980 (T/C) and rs9939609 (A/T) in Fat Mass and Obesity Associated gene (FTO) and rs17782313 (T/C) in Melanocortin 4 Receptor gene (MC4R). Thus, we aimed to investigate the association between these obesity-related SNPs and BC risk. One hundred BC patients and 148 healthy women from Santa Catarina, Brazil entered the study. SNPs were genotyped using Taqman assays. For statistical analyses SNPStats and SPSS softwares were used. Association analyses were performed by logistic regression and were adjusted for age and Body mass index (BMI). Multiple SNPs inheritance models (log-additive, dominant, recessive, codominant) were performed to determine odds ratios (ORs), assuming 95 % confidence interval (CI) and P value = 0.05 as the significance limit. When analyzed alone, FTO rs1121980 and rs9939609 did not show significant associations with BC development, however MC4R rs17782313 showed increased risk for BC even after adjustments (P-value = 0.032). Interestingly, the interaction of FTO and MC4R polymorphisms showed a powerful association with BC. We observed a 4.59-fold increased risk for woman who have the allele combination C/T/C (FTO rs1121980/FTO rs9939609/MC4R rs17782313) (P-value = 0.0011, adjusted for age and BMI). We found important and unpublished associations between these obesity-related genes and BC risk. These associations seem to be independent of their effect on BMI, indicating a direct role of the interaction between FTO and MC4R polymorphisms in BC development.     

Lifestyle factors modify obesity risk linked to PPARG2 and FTO variants in an elderly population: a cross-sectional analysis in the SUN Project

Genetic factors may interact with lifestyle factors to modify obesity risk. FTO and PPARG2 are relevant obesogenes. Our aim was to explore the effect of Pro12Ala (rs1801282) of PPARG2 and rs9939609 of FTO on obesity risk and to examine their interaction with lifestyle factors in an elderly population. Subjects (n = 978; aged 69 ± 6) were recruited from the SUN (Seguimiento Universidad de Navarra) Project. DNA was obtained from saliva, and lifestyle and dietary data were collected by validated self-reported questionnaires. Genotyping was assessed by RT-PCR plus allele discrimination. Subjects carrying the Ala allele of PPARG2 gene had a significantly increased obesity risk compared to non-carrier (Pro12Pro) subjects (OR, 1.66; 95  % CI, 1.01–2.74; p = 0.045). Greater obesity risk was also found in inactive or high carbohydrate intake subjects with the Ala12 allele of PPARG2 gene. Interestingly, subjects carrying the Ala allele of the PPARG2 gene and with a high CHO (>246 g/day) intake had an increased obesity risk compared to Pro12Pro subjects (OR, 2.67; 95 % CI, 1.3–5.46; p = 0.007; p for [CHO × PPARG2] interaction = 0.046). Moreover, in subjects with a high CHO intake, the co-presence of the Ala allele of PPARG2 gene and one minor A allele (rs9939609) of FTO gene did increase obesity risk (OR, 3.26; 95 % CI, 1.19–8.89; p = 0.021) when compared to non-carrier (Pro12Pro/TT) subjects. In conclusion, it appears that lifestyle factors may act as effect modifiers for obesity risk linked to Ala12 allele of the PPARG2 gene and the minor A allele of FTO gene in an elderly population.     

The obesity-associated polymorphisms FTO rs9939609 and MC4R rs17782313 and endometrial cancer risk in non-Hispanic white women

Overweight and obesity are strongly associated with endometrial cancer. Several independent genome-wide association studies recently identified two common polymorphisms, FTO rs9939609 and MC4R rs17782313, that are linked to increased body weight and obesity. We examined the association of FTO rs9939609 and MC4R rs17782313 with endometrial cancer risk in a pooled analysis of nine case-control studies within the Epidemiology of Endometrial Cancer Consortium (E2C2). This analysis included 3601 non-Hispanic white women with histologically-confirmed endometrial carcinoma and 5275 frequency-matched controls. Unconditional logistic regression models were used to assess the relation of FTO rs9939609 and MC4R rs17782313 genotypes to the risk of endometrial cancer. Among control women, both the FTO rs9939609 A and MC4R rs17782313 C alleles were associated with a 16% increased risk of being overweight (p = 0.001 and p = 0.004, respectively). In case-control analyses, carriers of the FTO rs9939609 AA genotype were at increased risk of endometrial carcinoma compared to women with the TT genotype [odds ratio (OR)  = 1.17; 95% confidence interval (CI): 1.03–1.32, p = 0.01]. However, this association was no longer apparent after adjusting for body mass index (BMI), suggesting mediation of the gene-disease effect through body weight. The MC4R rs17782313 polymorphism was not related to endometrial cancer risk (per allele OR = 0.98; 95% CI: 0.91–1.06; p = 0.68). FTO rs9939609 is a susceptibility marker for white non-Hispanic women at higher risk of endometrial cancer. Although FTO rs9939609 alone might have limited clinical or public health significance for identifying women at high risk for endometrial cancer beyond that of excess body weight, further investigation of obesity-related genetic markers might help to identify the pathways that influence endometrial carcinogenesis.     

The association between fat mass and obesity-associated (FTO) genotype and serum vitamin D level in breast cancer patients

The preventive effect of vitamin D against breast cancer can be influenced by gene polymorphisms. This study aimed to investigate the association between serum level of 25(OH) vitamin D and FTO genotype in breast cancer patients. A cross-sectional study was carried out on 180 newly diagnosed patients with breast cancer in Tehran, Iran. The blood samples were collected from the participants in order to assess the FTO gene rs9939609 polymorphism by the tetra-primer amplification refractory mutation system (Tetra-ARMS) PCR method. The serum level of 25(OH) vitamin D was measured using the direct competitive enzyme-linked immunosorbent assay (ELISA) method. The association between vitamin D and the FTO genotype in patients with breast cancer was assessed after adjustment for cofounders. The frequency of TT, AT and AA genotypes in the breast cancer patients were 43% (n = 77), 49% (n = 89) and 8% (n = 14), respectively. All patients with higher than 40 ng/dl of serum 25(OH) vitamin D had one or two copies of FTO rs9939609 risk allele (p = 0.019). No linear association was found between the number of FTO risk allele and the level of serum vitamin D. All patients with high serum level of 25(OH) vitamin D had one or two copies of FTO rs9939609 risk allele. FTO gene polymorphisms may counteract the beneficial effects of vitamin D in breast cancer prevention. Further studies can help to better understand the genetic factors predisposing to breast cancer and their effect on the association between vitamin D and breast cancer.     

Association of the common FTO-rs9939609 polymorphism with type 2 diabetes,independent of obesity-related traits in a Vietnamese population

Type 2 diabetes (T2D) is a complex disorder resulting from both genetic and environmental factors in its pathogenesis. A case − control study was designed with subjects recruited from a general population to investigate whether the association between T2D and the common T > A polymorphism (rs9939609) in fat mass and obesity associated (FTO) gene is mediated by obesity-related measurements, considering the contribution of socio-economic status and lifestyle factors. The significant association between the FTO rs9939609 polymorphism and T2D was first observed in the model unadjusted (OR per A allele = 1.61, 95% CI = 1.06–2.44, P = 0.024). It remained consistently replicated in the final model after adjustments for sex, age, systolic blood pressure, socio-economic status, lifestyle factors, and obesity-related measurements (body mass index, waist–hip ratio, body fat percentage, and body adiposity index), showing an increased T2D risk with an additive effect of the alleles (ORs per A allele = 1.80–1.92, 95% CI = 1.09–3.19, P < 0.05). The FTO-rs9939609 polymorphism, systolic blood pressure, and waist–hip ratio were the most significant independent predictors for T2D, in which the power of the adjusted prediction model was 0.769. In conclusion, the study suggested that the FTO-rs9939609 polymorphism was significantly associated with the increased risk of T2D, independent of obesity-related measurements in a Vietnamese population.     

Association of a common rs9939609 variant in the fat mass and obesity-associated (<Emphasis Type="Italic">FTO</Emphasis>) gene with obesity and metabolic phenotypes in a Taiwanese population: a replication study

It is a key challenge to conduct reproducibility in genetic research, especially association studies in obesity. While susceptibility of a single-nucleotide polymorphism (SNP), rs9939609, in the fat mass and obesity-associated (FTO) gene to obesity has been reported in various populations, data from Asians is less conclusive. This replication study was carried out to test whether the FTO rs9939609 SNP is a predictive factor for obesity and obesity-related metabolic traits in a Taiwanese population. A total of 1188 Taiwanese subjects were recruited for this study. The FTO rs9939609 SNP was genotyped by the Taqman assay. Obesity-related metabolic traits such as triglyceride, waist circumference, systolic and diastolic blood pressure, total cholesterol, creatinine, alanine aminotransferase and fasting glucose were measured. Our data revealed that the FTOrs9939609 SNP exhibited a significant association with obesity (BMI \(\geqq \) 30 kg/m ²) among the subjects (P= 0.026). However, the FTO rs9939609 SNP did not exhibit any significant association with obesity-related metabolic traits among the subjects. Our results indicated that the FTO rs9939609 SNP may be linked with the risk of obesity in Taiwanese subjects.     

Association between Fat Mass- and Obesity- Associated (FTO) Gene Polymorphism and Polycystic Ovary Syndrome: A Meta-Analysis

Aims

Many studies have investigated the relationship between FTO gene polymorphism and polycystic ovary syndrome (PCOS) susceptibility but revealed mixed results. In this study, we aimed to perform a meta-analysis to clarify this association.

Methods

Published literature from PubMed, Embase and CNKI was retrieved. Meta-analysis was performed to calculate pooled odds ratio (OR) with 95% confidence interval (CI) using the random- or fix- effects model.

Results

A total of 5 studies (4778 cases and 4272 controls) were included in our meta-analysis. The results suggested that FTO rs9939609 polymorphism (or its proxy) was marginally associated with PCOS risk after adjustment for body mass index (BMI) (OR = 1.26; 95%CI: 1.02–1.55). However, the marginal association was not stable after sensitivity analysis. In the subgroup analysis by ethnicity, the association was significant in East Asians (OR = 1.43, 95%CI = 1.30–1.59) but not in Caucasians (OR = 1.04, 95%CI = 0.85–1.29).

Conclusions

Our present meta-analysis indicated that FTO rs9939609 polymorphism (or its proxy) might not be associated with risk of PCOS in overall population. However, in East Asians, there might be a direct association between FTO variant and PCOS risk, which is independent of BMI (adiposity).     

The common SNP (rs9939609) in the FTO gene modifies the association between obesity and high blood pressure in Chinese children

Previous studies have suggested that common variants in fat mass- and obesity-associated (FTO) gene are associated with body mass index (BMI) and the risk of obesity. Since obesity plays an important role in the etiology of high blood pressure (HBP), we aim to investigate the association between obesity and HBP in a population with different variants of the FTO gene. A total of 3,494 children (1,775 boys, 50.8 %) aged 6–18 years were recruited for measuring pubertal status, BMI and systolic and diastolic blood pressure. The single nucleotide polymorphism rs9939609 of the FTO gene was genotyped. The blood pressure levels increased by 1.4, 1.5 and 1.8 mmHg for systolic blood pressure and 0.8, 0.9 and 1.2 mmHg for diastolic blood pressure per 1-unit BMI increase in subjects carrying TT, TA and AA genotypes, respectively. After stratifying for FTO rs9939609 genotypes (TT, TA and AA), the odds ratios (95 % confidence intervals) of HBP in obese versus non-obese children were 4.26 (3.18–5.71), 5.13 (2.96–8.90) and 10.37 (1.59–67.43), respectively, with adjustment for age, gender and pubertal status. The FTO rs9939609 SNP modifies the effect of obesity on HBP in Chinese children, with obese ones carrying the AA homozygous genotype of the FTO rs9939609 having the highest risk of developing HBP.     

The Effects of Genetic Variation in FTO rs9939609 on Obesity and Dietary Preferences in Chinese Han Children and Adolescents

The association of the rs9939609 single nucleotide polymorphism in FTO gene with obesity has been extensively investigated in studies of populations of European, African, and Asian ancestry. However, inconsistent results have been reported in Asian populations, and the relationship of FTO variation and dietary behaviors has only rarely been examined in Chinese children and adolescents. The aim of this study was to assess the association of rs9939609 with obesity and dietary preferences in childhood in a Chinese population. Epidemiological data including dietary preferences were collected in interviews using survey questionnaires, and rs9939609 genotype was determined by real-time PCR. The associations of rs9939609 genotypes with obesity and dietary preferences were analyzed by multivariate logistic regression using both additive and dominant models. The results showed that subjects with a TA or AA genotype had an increased risk of obesity compared with the TT participants; the odds ratios (ORs) were 1.47 (95% CI: 1.25–1.71, P = 1.73×10⁻⁶), and 3.32 (95% CI: 2.01–5.47, P = 2.68×10⁻⁶), respectively. After adjusting for age and gender, body mass index, waist circumference, hip circumference, systolic blood pressure, diastolic blood pressure, fasting blood glucose, triglycerides, and low-density lipoprotein cholesterol were higher, and high-density lipoprotein cholesterol was lower in TA and AA participants than in those with the TT genotype. After additionally controlling for body mass index, the association remained significant only for systolic blood pressure (P = 0.005). Compared with TT participants, those with the AA genotype were more likely to prefer a meat-based diet (OR = 2.81, 95% CI: 1.52–5.21). The combined OR for obesity in participants with TA/AA genotypes and preference for a meat-based diet was 4.04 (95% CI: 2.8–5.81) compared with the TT participants who preferred a plant-based diet. These findings indicate the genetic variation of rs9939609 is associated with obesity and dietary preferences in Chinese children and adolescents.     

Dietary Energy Density Affects Fat Mass in Early Adolescence and Is Not Modified by FTO Variants

Background

Dietary energy density (DED) does not have a simple linear relationship to fat mass in children, which suggests that some children are more susceptible than others to the effects of DED. Children with the FTO (rs9939609) variant that increases the risk of obesity may have a higher susceptibility to the effects of DED because their internal appetite control system is compromised. We tested the relationship between DED and fat mass in early adolescence and its interaction with FTO variants.

Methods and Findings

We carried out a prospective analysis on 2,275 children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). Diet was assessed at age 10 y using 3-day diet diaries. DED (kJ/g) was calculated excluding drinks. Children were genotyped for the FTO (rs9939609) variant. Fat mass was estimated at age 13 y using the Lunar Prodigy Dual-energy X-ray Absorptiometry scanner. There was no evidence of interaction between DED at age 10 y and the high risk A allele of the FTO gene in relation to fat mass at age 13 y (β = 0.005, p = 0.51), suggesting that the FTO gene has no effect on the relation between DED at 10 y and fat mass at 13 y. When DED at 10 y and the A allele of FTO were in the same model they were independently related to fat mass at 13 y. Each A allele of FTO was associated with 0.35±0.13 kg more fat mass at 13 y and each 1 kJ/g DED at 10 y was associated with 0.16±0.06 kg more fat mass at age 13 y, after controlling for misreporting of energy intake, gender, puberty, overweight status at 10 y, maternal education, TV watching, and physical activity.

Conclusions

This study reveals the multi-factorial origin of obesity and indicates that although FTO may put some children at greater risk of obesity, encouraging a low dietary energy density may be an effective strategy to help all children avoid excessive fat gain.     

The rs9939609 polymorphism in the fat mass and obesity associated (FTO) gene is associated with obesity in Tunisian population

Abstract

Context: Variations in the fat mass and obesity-associated gene (FTO) has been associated with obesity in many populations, but the results are conflicting.

Objective: The aim of this study was to evaluate the effect of the rs9939609 polymorphism in the FTO gene on obesity risk and plasma leptin, adiponectin, insulin and lipid concentrations in Tunisians.

Materials and methods: Four hundred and ninety-four subjects with obesity and 334 non-obese participated in this study. The rs9939609 (T/A) genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results: Significant differences in genotype frequencies were observed between cases and controls. In the separate analysis by gender, the association between the AA genotype and obesity was statistically significant in women but not in men. After stratification by obesity class this association remains only with obesity class III.

Discussion: Our study is in agreement with studies on Caucasian, Portuguese and Cebu Filipino populations where a gender-specific association was found between rs9939609 polymorphism and obesity. It is also in agreement with studies on Mexican, Spanish and European populations, where an association was found with obesity class III.

Conclusion: The rs9939609 polymorphism of FTO gene is associated with obesity, especially obesity class III in women.     

Common variant (rs9939609) in the<Emphasis Type="Italic"> FTO</Emphasis> gene is associated with metabolic syndrome

Recent genome-wide association studies have showed that common variant (rs9939609) in fat mass and obesity associated (FTO) gene was significantly associated with type 2 diabetes through an effect on human body mass index/obesity. Further studies have suggested that this variant was also involved in the development of metabolic syndrome (MetS). However, the results have been inconsistent. In this study, we performed a meta-analysis to clarify the association between rs9939609 polymorphism and the risk of MetS. Published literature from PubMed, EMBASE and other databases were searched. All studies assessing the association between rs9939609 polymorphism and the risk of MetS were identified. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed-effects model. Thirteen studies (8,370 cases and 23,156 controls) using NCEP ATPIII criteria for MetS were pooled with a meta-analysis. The overall result showed that there was a statistically significant association between rs9939609 polymorphism and MetS risk (OR = 1.11, 95% CI = 1.06–1.17). Subgroup analysis based on ethnicity showed that effect size was only statistically significant in Europeans (OR = 1.11, 95% CI = 1.05–1.16). Eight studies (1,256 cases and 2,551 controls) using IDF criteria for MetS were pooled with a meta-analysis. The overall analysis suggested that rs9939609 polymorphism was significantly associated with MetS risk (OR = 1.32, 95% CI = 1.13–1.54). Subgroup analysis stratified by ethnicity suggested that effect size was only statistically significant in Asians (OR = 1.33, 95% CI = 1.10–1.61). Our results suggested that FTO rs9939609 polymorphism was significantly associated with the increased risk of MetS in European and Asian populations. Mechanistic investigation is also needed to clarify the effect of FTO gene in the predisposition to MetS.     

Polymorphisms in FTO and near TMEM18 associate with type 2 diabetes and predispose to younger age at diagnosis of diabetes

Variations in the FTO gene and near the TMEM18 gene are risk factors for common form of obesity, but have also been linked with type 2 diabetes (T2D). Our aim was to investigate the contribution of these variants to risk of T2D in a population in Latvia. Four single nucleotide polymorphisms (SNP) in the first and fourth intronic regions of FTO and one close to TMEM18 were genotyped in 987 patients with T2D and 1080 controls selected from the Latvian Genome Data Base (LGDB). We confirmed association of SNPs in the first intron (rs11642015, rs62048402 and rs9939609) of FTO and rs7561317 representing the TMEM18 locus with T2D. Association between SNP in FTO and T2D remained significant after correction for body mass index (BMI). The rs57103849 located in the fourth intron of FTO and rs7561317 in TMEM18 showed BMI independent association with younger age at diagnosis of T2D. Our results add to the evidence that BMI related variants in and near FTO and TMEM18 may increase the risk for T2D not only through secondary effects of obesity. The influence of variants in the fourth intron of the FTO gene on development of T2D may be mediated by mechanisms other than those manifested by SNPs in the first intron of the same gene.     

FTO Is Associated with Aortic Valve Stenosis in a Gender Specific Manner of Heterozygote Advantage: A Population-Based Case-Control Study

Background

Single nucleotide polymorphisms (SNPs) within the Fat mass and obesity associated (FTO) gene have been linked with increased body weight. However, the data on an association of FTO with cardiovascular diseases remains conflicting. Therefore, we ascertained whether FTO is associated with aortic valve stenosis (AVS), one of the most frequent cardiovascular diseases in the Western world.

Methods and Findings

In this population-based case-control study the FTO SNP rs9939609 was analyzed in 300 German patients with AVS and 429 German controls of the KORA survey S4, representing a random population. Blood samples were collected prior to aortic valve replacement in AVS cases and FTO rs9939609 was genotyped via ARMS-PCR. Genotype frequencies differed significantly between AVS cases and KORA controls (p = 0.004). Separate gender-analyses uncovered an association of FTO with AVS exclusively in males; homozygote carriers for the risk-allele (A) had a higher risk to develop AVS (p = 0.017, odds ratio (OR) 1.727; 95% confidence interval (CI) 1.087–2.747, recessive model), whereas heterozygote carriers for the risk-allele showed a lower risk (p = 0.002, OR 0.565, 95% CI 0.384–0.828, overdominant model). After adjustment for multiple co-variables, the odds ratios of heterozygotes remained significant for an association with AVS (p = 0.008, OR 0.565, 95% CI 0.369–0.861).

Conclusions

This study revealed an association of FTO rs9939609 with AVS. Furthermore, this association was restricted to men, with heterozygotes having a significantly lower chance to develop AVS. Lastly, the association between FTO and AVS was independent of BMI and other variables such as diabetes mellitus.     

Statistical and Biological Gene-Lifestyle Interactions of MC4R and FTO with Diet and Physical Activity on Obesity: New Effects on Alcohol Consumption

Background

Fat mass and obesity (FTO) and melanocortin-4 receptor (MC4R) and are relevant genes associated with obesity. This could be through food intake, but results are contradictory. Modulation by diet or other lifestyle factors is also not well understood.

Objective

To investigate whether MC4R and FTO associations with body-weight are modulated by diet and physical activity (PA), and to study their association with alcohol and food intake.

Methods

Adherence to Mediterranean diet (AdMedDiet) and physical activity (PA) were assessed by validated questionnaires in 7,052 high cardiovascular risk subjects. MC4R rs17782313 and FTO rs9939609 were determined. Independent and joint associations (aggregate genetic score) as well as statistical and biological gene-lifestyle interactions were analyzed.

Results

FTO rs9939609 was associated with higher body mass index (BMI), waist circumference (WC) and obesity (P<0.05 for all). A similar, but not significant trend was found for MC4R rs17782313. Their additive effects (aggregate score) were significant and we observed a 7% per-allele increase of being obese (OR = 1.07; 95%CI 1.01–1.13). We found relevant statistical interactions (P<0.05) with PA. So, in active individuals, the associations with higher BMI, WC or obesity were not detected. A biological (non-statistical) interaction between AdMedDiet and rs9939609 and the aggregate score was found. Greater AdMedDiet in individuals carrying 4 or 3-risk alleles counterbalanced their genetic predisposition, exhibiting similar BMI (P = 0.502) than individuals with no risk alleles and lower AdMedDiet. They also had lower BMI (P = 0.021) than their counterparts with low AdMedDiet. We did not find any consistent association with energy or macronutrients, but found a novel association between these polymorphisms and lower alcohol consumption in variant-allele carriers (B+/−SE: −0.57+/−0.16 g/d per-score-allele; P = 0.001).

Conclusion

Statistical and biological interactions with PA and diet modulate the effects of FTO and MC4R polymorphisms on obesity. The novel association with alcohol consumption seems independent of their effects on BMI.     

A meta-analysis on associations of FTO,MTHFR and TCF7L2 polymorphisms with polycystic ovary syndrome

BackgroundWe aimed to better clarify the relationship between FTO/MTHFR/TCF7L2 polymorphisms and PCOS in a larger combined population by performing a meta-analysis.MethodsEligible articles were retrieved from Pubmed, Embase, Web of Science and CNKI. Review Manager Version was used to perform statistical analyses.ResultsForty-six studies were included for this meta-analysis. FTO rs9939609 polymorphism was found to be significantly associated with PCOS under dominant, recessive, over-dominant and allele comparisons, MTHFR rs1801131 polymorphism was found to be significantly associated with PCOS under recessive and allele comparisons, and MTHFR rs1801133 polymorphism was also found to be significantly associated with PCOS under dominant, recessive and allele comparisons in general population. In subgroup analyses, we found that positive results were mainly driven by the Asians.ConclusionsCollectively, this meta-analysis proved that FTO rs9939609, MTHFR rs1801131 and MTHFR rs1801133 polymorphisms may serve as predisposing factors of PCOS, especially for Asians.