The obesity associated FTO gene polymorphism and the risk of preeclampsia in Iranian women: A case-control study

BACKGROUND

Preeclampsia (PE) is one of the leading disorders in pregnant women with maternal and fetal complications. Obesity is considered an important risk factor for the development of PE. Genetic variations in fat mass and obesity associated (FTO) gene may play a role in the development of PE. This study aimed to investigate the possible association between FTO gene rs9939609 and PE risk in a sample of Iranian pregnant women.

MATERIAL AND METHODS

In this case-control study, 312 pregnant women were included, including 128 with PE and 184 without PE. Demographic data and blood samples were obtained from all individuals. The genotyping of rs9939609 polymorphisms was performed by the tetra-primer amplification refractory mutation system-polymerase chain reaction (TP-ARMS-PCR) method, and the results of TP-ARMS-PCR were confirmed using DNA sequencing.

RESULTS

The genotype frequency was 50%, 47.7%, and 2.3% in pregnant patients and 37%, 47.8%, and 15.2% in healthy controls for TT, AT, and AA, respectively. The risk of PE was significantly reduced in the pregnant women having the AA genotype.

CONCLUSION

Based on the results of the present study, rs9939609 polymorphism in the FTO gene may play a protective role against PE. However, further studies are warranted. [Figure: see text].

Lack of association of the alpha-ketoglutarate-dependent dioxygenase (FTO) gene polymorphisms with pulmonary tuberculosis risk: a systematic review and meta-analysis

Objective

Our meta-analysis aims to explore the association of two single nucleotide variants; rs9939609 and rs8050136, within the FTO gene with risk of pulmonary tuberculosis (PTB).

Methods

The association of two single nucleotide variants with PTB in three genetic models was evaluated using pooled odds ratios (ORs) with 95% CIs.

Results

No significant association was observed between the rs9939609 polymorphism and PTB when assuming an allelic model (OR: 1.10; 95% CI: 0.85-1.41; P=0.47; I2 = 64.98%), a recessive model (OR: 2.04; 95% CI: 0.87-4.77; P=0.10; I2 = 67.18%), or a dominant model (OR: 0.96; 95% CI: 0.83-1.11; P=0.56; I2 = 27.45%). Likewise, no association was observed between rs8050136 polymorphism and PTB when assuming allelic model (OR: 1.17; 95% CI: 0.87-1.58; P=0.31; I2 = 64.20%) or recessive model (OR: 1.04; 95% CI: 0.32-3.38; P=0.95; I2 = 68.82%) or dominant model (OR: 1.22; 95% CI: 0.87-1.71; P=0.26; I2 = 58.69%).

Conclusion

There might be no association between the rs9939609 and rs8050136 variants in the FTO gene, and the risk of PTB.

Association Study of BDNF, SLC6A4, and FTO Genetic Variants with Schizophrenia Spectrum Disorders

Schizophrenia spectrum disorders (patients with a diagnosis of schizophrenia, schizotypal, and delusional disorders: F20-F29 according to International Classification of Diseases 10th revision (ICD-10)) are considered highly heritable heterogeneous psychiatric conditions. Their pathophysiology is multifactorial with involved dysregulated serotonergic neurotransmission and synaptic plasticity. The present study aimed to evaluate the association of SLC6A4 (5-HTTLPR), FTO (rs9939609), and BDNF (rs6265, rs962369) polymorphisms with schizophrenia spectrum disorders in Slovak patients. We analyzed the genotypes of 150 patients with schizophrenia, schizotypal, and delusional disorders and compared them with genotypes from 178 healthy volunteers. We have found a marginally protective effect of LS + SS genotypes of 5-HTTLPR variant of the serotonin transporter SLC6A4 gene against the development of schizophrenia spectrum disorders, but the result failed to remain significant after Bonferroni correction. Similarly, we have not proven any significant association between other selected genetic variants and schizophrenia and related disorders. Studies including a higher number of subjects are warranted to reliably confirm the presence or absence of the studied associations.

Interactive effects of FTO rs9939609 and obesogenic behavioral factors on adiposity-related anthropometric and metabolic phenotypes

Numerous genetic variants have been linked to obesity predisposition, however, the interplay of genetic and behavioral factors is very crucial in determining the final phenotype. Therefore, this study examined the interactive effects of the FTO rs9939609 and various obesogenic behavioral factors on adiposity-related anthropometric and metabolic phenotypes in a sample of Pakistani population. A total of 612 participants encompassing 306 overweight/obese (cases) and an equal number (306) of age- and sex-matched normal-weight (controls) individuals were included in the study. Adiposity-related anthropometric parameters were collected by taking corresponding body measurements by following standard procedures. The metabolic parameters were assessed by performing corresponding biochemical assays. A standard questionnaire was devised for the collection of adiposity-related behavioral information. The FTO rs9939609 was genotyped by employing TaqMan allelic discrimination assay. The data was analyzed by using SPSS software. Interactive effects of the FTO rs9939609 and behavioral factors on obesity-related anthropometric and metabolic phenotypes were examined via linear regression by adjusting potential confounders and making correction for multiple comparisons. The results implied that the interaction between the FTO rs9939609 and low physical activity may significantly increase various adiposity-related anthropometric variables (p < 0.05). However, no such interactive effects were found on any adiposity-related metabolic variable. In conclusion, the interaction between the FTO rs9939609 and low physical activity may have a significant impact on obesity-related anthropometric traits in the Pakistani population.

Exploring Dietary Intake in Adults with Severe Obesity and Associations with the FTO rs9939609 Genotypes

Background

Few have studied the associations between rs9939609 genotypes in the obesity candidate locus FTO and energy and nutrient intakes and meal frequencies in adults with severe obesity. We are unaware of studies that have assessed adherence to key dietary recommendations in this population, at least in Norway. Increased knowledge of genotype associations with dietary factors could improve personalized obesity therapy.

Objectives

The present study aimed to explore how the rs9939609 genotypes associate with dietary variables and adherence to key dietary recommendations in a sample of adults with severe obesity.

Methods

A cross-sectional observation study designed to have similar numbers of participants with genotypes TT, AT, and AA included 100 patients (70% women) with median (25th, 75th percentile) age 42 (32, 50) y and BMI 42.8 (39.5, 46.4) kg/m2. We assessed intakes of food groups, energy, and macro- and micronutrients from three 24-h dietary recalls and meal frequencies. Genotype associations were analyzed using regression analyses. Reported intakes were evaluated against national diet recommendations.

Results

Using a significance level of 0.01, we found no genotype associations with energy intake, energy density, adherence to recommendations, or meal frequency but tendencies of associations with energy adjusted protein intake (AA > AT, P = 0.037; AT > TT, P = 0.064), food groups milk and cream (AT > TT, P = 0.029), and Mixed dishes (AA > TT, P = 0.039). Few participants complied with recommendations for intakes of whole grains (21%), fruits and vegetables (11%), and fish (37%); however, 67% followed the recommendation to limit added sugar. Less than 20% had recommended intakes of vitamin D and folate.

Conclusions

In our patients with severe obesity, we found tendencies of associations between the FTO rs9939609 genotypes and diet but no significant associations at the 0.01 level and below. Few met key food-based diet recommendations, suggesting that the food habits in this population pose an increased risk of nutrient deficiencies. Curr Dev Nutr 2023;xx:xx.

A single FTO gene variant rs9939609 is associated with weight change and insulin resistance improvement in response to a robotic sleeve gastrectomy in individuals with severe obesity

BACKGROUND

Genetic mechanisms have been involved in the weight response secondary to bariatric surgery.

OBJECTIVE

The aim of our study was to evaluate the effects of the rs9939609 genetic variant on weight loss and metabolic parameters after sleeve gastrectomy.

SETTING

Tertiary hospital.

METHODS

A total of 95 participants were enrolled. Co-morbidities, biochemical evaluation, and anthropometric parameters were registered before and after 3-, 6-, and 12-month follow-up. Genotype of the rs9939609 fat mass and obesity-associated (FTO) gene was evaluated.

RESULTS

We grouped the participants into 2 groups: carriers of A allele (TA+AA, 69.5%) and noncarriers of A allele (TT, 30.5%). We detected a statistically significant reduction of blood pressure, biochemical, and anthropometric parameters at 3 times during follow-up. After 6 months, changes of some parameters were greater in non-A allele carriers: weight (-39.6 + 4.0 kg versus -24.6 + 2.8 kg; P = .02), waist circumference (-21.1 + 2.1 cm versus -16.2 + 1.8 cm; P = .04), insulin (-12.3 + .9 mUI/L versus -8.9.1 + .2 mUI/L; P = .02), and homeostasis model assessment of insulin resistance (-3.1 + .1 units versus -2.3 + .1 units; P = .02 ). After 12 months, changes of the aforementioned parameters remained greater in non-A allele carriers. The percentage of participants with diabetes diminished earlier in the non-A allele carriers than A allele carriers at 6-month follow-up. The percentage of participants with diabetes at the end of the study was lower in non-A allele carriers (3.4% versus 12.1%; P = .02).

CONCLUSIONS

Our data suggest that non-A allele carriers of the genetic variant (rs9939609) of the FTO gene showed a better improvement of anthropometric and insulin levels in non-A allele carriers after a robotic sleeve gastrectomy. Both improvements are associated with a lower percentage of participants with diabetes at 12 months.

Breastfeeding moderates the relationship between fat mass and obesity-associated gene rs9939609 and body mass index among adolescents

OBJECTIVE

Breastfeeding, which is important for early growth, is a possible moderator of genetic influence, such as the effect of the fat mass and obesity-associated gene (FTO) on body mass index (BMI). The aim of this study was to assess the moderating effect of breastfeeding duration on the relationship between FTO rs9939609 and BMI in a Caucasian sample.

METHODS

Adolescents born in 1997 and in 1999, who were living in the Swedish county Västmanland in 2012, were invited to participate in the Survey of Adolescent Life in Västmanland. The adolescents and their parents completed self-reported questionnaires in 2012, 2015, and 2018. Genotyping of rs9939609 T > A polymorphism was conducted from saliva DNA samples. Interaction effects of parental reported breastfeeding duration in months, including regions of significance, on the relationship between rs9939609 and BMI plus overweight were assessed.

RESULTS

Considering physical activity levels, parental reported breastfeeding duration was a moderator of the relationship between rs9939609 and BMI for the younger (regions of significance = <1.6 and >28.1 months) and older adolescents (region of significance = >19.9 months), but not for the young adults. Plots of the association between breastfeeding duration and BMI showed higher BMI for AA with short breastfeeding, but lower BMI with longer breastfeeding than AT and TT. Longer breastfeeding lowered the odds for overweight among the younger adolescents, especially among AA individuals.

CONCLUSION

Rs9939609 AA individuals were more susceptible than AT and TT individuals to both short and long breastfeeding durations, which is consistent with the differential susceptibility hypothesis. FTO rs9939609 AA might be a plasticity variant with differential susceptibility to environmental influences. Breastfeeding duration may be one of many factors that affect the relationship between rs9939609 and BMI.

Polymorphisms on rs9939609 FTO and rs17782313 MC4R genes in children and adolescent obesity: A systematic review

The aim of this review was to assess whether the presence of rs9939609 and rs17782313 polymorphisms increase the risk for obesity among children and adolescents. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and it was registered in PROSPERO. The search was performed in the PubMed/Medline, The Cochrane Library, and Web of Science databases. The risk of bias of the studies was accessed using the Newcastle-Ottawa scale and JBI Critical Appraisal Checklist for Analytical. The search of the databases retrieved 859 references. Twelve studies were eligible to be included in this systematic review. Five studies founded a positive association between overweight and obesity in children and adolescents with the presence of the rs17783213 and four studies with rs9939609. Three studies did not find an association between overweight and obesity in children and adolescents with the presence of rs17782313 or rs9939609. One found a protective effect for obesity in individuals with risk A allele referring to rs9939609, one found a synergistic effect in relation to the presence of polymorphisms rs17782313 and rs9939609 for obese phenotype, and one observed that the presence together of the rs9939609, rs17782313, and rs12970134 MC4R were significant for the presence of obesity in children and adolescents. The results suggest that depending on the population evaluated and ethnicity, the polymorphisms rs17782313 and rs9939609 could be associated with overweight and obesity in children and adolescents.

Fat mass and obesity-associated (FTO) gene epigenetic modifications in gestational diabetes: new insights and possible pathophysiological connections

AIMS

Gestational diabetes mellitus (GDM) can lead to short- and long-term complications for the child. Epigenetic alterations could contribute to explaining the metabolic disturbances associated with foetal programming. Although the role of the FTO gene remains unclear, it affects metabolic phenotypes probably mediated by epigenetic mechanisms. The aim of this study was to assess whether placental DNA epigenetic modifications at FTO promoter-associated cysteine-phosphate-guanine (CpG) sites are correlated with GDM. A secondary aim was to evaluate the association between the placental FTO DNA methylation and the maternal metabolic traits in women with and without GDM.

METHODS

Socio-demographic characteristics, clinical parameters at the third trimester of pregnancy, Mediterranean diet adherence, and physical activity were assessed in 33 GDM women and 27 controls. Clinical information about the newborns was registered at birth. The FTO rs9939609 (T > A) was genotyped.

RESULTS

No association between FTO DNA methylation and GDM was found. DNA methylation on the maternal side at the CpG1 was associated with maternal smoking in GDM (p = 0.034), and DNA methylation at the CpG3 was correlated with smoking or former smoking in controls (p = 0.023). A higher level of TGs was correlated with higher foetal placental DNA methylation at the CpG2 (p = 0.036) in GDM. An inverse association between HDL-C and maternal placental DNA methylation at the CpG3 in controls (p = 0.045) was found. An association between FTO rs9939609 and neonatal birthweight (p = 0.033) was detected.

CONCLUSIONS

In the awareness that the obesity pathophysiology is complex, the study adds a piece to this intricate mosaic.

The role of the FTO gene in the relationship between depression and obesity. A systematic review

Depression and obesity are major global health problems that frequently co-occur. The FTO gene has one of the strongest links with obesity and high body mass index (BMI) in humans. Besides, this gene is highly expressed in the brain, may play a role in the nervous system, and could confer risk for depression, although scarce literature is available in this respect. We perform a systematic review of the relationship between FTO and both conditions. We selected original articles with observational design or reviews, where depression was assessed with ICD-10, DSM-5 or previous versions, published from 2012 (when the first related paper was published) to November 2020, performed in adults, in English or Spanish and having an optimal methodological quality (evaluated with SIGN checklist). Five original studies were finally included. The results regarding the role of FTO in depression-obesity comorbidity were inconclusive. This leads us to endorse further research covering the role of this gene on both conditions, emphasising a more precise characterization of depression, in order to confirm this role.

Association of FTO rs9939609 polymorphism with serum leptin, insulin, adiponectin, and lipid profile in overweight adults

FTO gene polymorphisms are associated with obesity and food intake. This study aimed to investigate the association of FTO rs9939609 polymorphism genotypes with serum glucose, lipid profile and serum hormones level. This cross-sectional study was carried out on 196 randomly selected overweight adults. Anthropometric measurements including weight, height, body mass index (BMI), fat mass, and fat-free mass were assessed. Serum TGs, total cholesterol, HDL cholesterol, LDL cholesterol, glucose and insulin levels were measured. The FTO gene was Genotyped for rs9939609 polymorphism. Dietary intake was assessed by avalid 168-item semi-quantitative food frequency questionnaire (FFQ). The homozygotes for the FTO rs9939609 risk allele (A) had higher serum leptin (p = 0.005, F: 5.131) and lower HDL (p = 0.001, F: 7.687) level than TT genotype. The differences between TT and AT genotypes were not significant. The association remained significant for HDL level after adjustments for age and sex, calorie intake, physical activity, and BMI. The association between rs9939609 polymorphism genotypes and leptin was disappeared after adjustments for calorie intake and physical activity. In conclusion, rs9939609 risk allele was associated with higher serum leptin and lower HDL levels in overweight people. Further studies are warranted.

Rs9939609 polymorphism of the fat mass and obesity-associated (FTO) gene and metabolic syndrome susceptibility in the Chinese population: a meta-analysis

PURPOSE

The relationship between the rs9939609 allele of fat mass and obesity-associated (FTO) gene and metabolic syndrome (MS) susceptibility has been evaluated by many studies, however, the results still remained controversial in the Chinese population. In order to provide more accurate results, we performed this meta-analysis.

METHODS

We searched PubMed, and Wanfang Med Online in both English and Chinese, and eight eligible studies comprising of 5345 cases and 9523 controls were eventually selected into our meta-analysis. The meta-analysis was performed using the STATA 12.0 software.

RESULTS

In pooled analysis, the FTO gene rs9939609 polymorphism significantly increased MS susceptibility under per-allele comparisons (A vs. T) (OR 1.21, 95% CI 1.10-1.35, P < 0.001) and in dominant model (OR 1.35, 95% CI 1.13-1.62, P < 0.001). Subgroup analyses under per-allele comparisons (A vs. T) indicated that the elevated risk was observed in adults (OR 1.26, 95% CI 1.08-1.47, P = 0.003) but not in children and adolescents (OR 1.14, 95% CI 0.95-1.36, P = 0.17), and that the risk for increasing MS was only identified in IDF groups (OR 1.22, 95% CI 1.03-1.43, P = 0.018) but not in NCEP ATP III groups (OR 1.14, 95% CI 0.95-1.36, P = 0.17); in both population-based (PB) and hospital-based (HB) groups, A alleles of rs9939609 appeared to be linked to increased MS susceptibilities (HB group: OR 1.51, 95% CI 1.10-2.08, P = 0.01; PB group: OR 1.19, 95% CI 1.09-1.30, P < 0.001). No significant association was established in dominant model subgroup analyses except PB group (OR 1.29, 95% CI 1.05-1.53, P < 0.001).

CONCLUSION

Our results suggested that the FTO gene rs9939609 polymorphism significantly increased MS susceptibility in Chinese. Our results should be verified by well-designed studies with larger sample size.

Genetic Epidemiology in Latin America: Identifying Strong Genetic Proxies for Complex Disease Risk Factors

Epidemiology seeks to determine the causal effects of exposures on outcomes related to the health and wellbeing of populations. Observational studies, one of the most commonly used designs in epidemiology, can be biased due to confounding and reverse causation, which makes it difficult to establish causal relationships. In recent times, genetically informed methods, like Mendelian randomization (MR), have been developed in an attempt to overcome these disadvantages. MR relies on the association of genetic variants with outcomes of interest, where the genetic variants are proxies or instruments for modifiable exposures. Because genotypes are sorted independently and at random at the time of conception, they are less prone to confounding and reverse causation. Implementation of MR depends on, among other things, a strong association of the genetic variants with the exposure, which has usually been defined via genome-wide association studies (GWAS). Because GWAS have been most often carried out in European populations, the limited identification of strong instruments in other populations poses a major problem for the application of MR in Latin America. We suggest potential solutions that can be realized with the resources at hand and others that will have to wait for increased funding and access to technology.

Association of FTO common variant (rs9939609) with body fat in Turkish individuals

Background

Variations in the fat mass and obesity-associated (FTO) gene (16q12.2) are associated with obesity in some populations. This study aimed to determine the relationship between FTO gene polymorphism and adiposity&related markers in Turkish adults was aimed.

Methods

The present study included 200 participants aged 18–65 years, who were genotyped for variants of the FTO gene (rs9939609). Anthropometric measurements were performed. Body compositions were analyzed with Tanita BC 545 N Inner ScanTM. Infrared analyzer (VISCANTM) was also used to determinate the degree of abdominal fat. Body mass index (BMI), body adiposity index (BAI) and lipid accumulation products (LAP) index which are used in body fat estimation were calculated. Body fat amounts were classified using gender-based cut-offs. Odds ratio (OR) and 95% confidence interval (CI) were calculated to determine the risk of having a high body fat amount associated with the risk allele.

Results

The frequency of the rs9939609 AA genotype was 19.0%, which was 42.5% for the AT genotype and 38.5% for the TT genotype (wild type). AA genotype was found to be higher in females than in males (26.0 and 12.0%, respectively). The total body fat amount of the individuals with AA genotype was high (28.5 ± 9.25%) compared to AT (27.0 ± 10.31%) and TT (23.7 ± 10.62%) genotype (p < 0.05). However, there was no difference in abdominal fat amounts (%) (AA:38.6%, AT:36.2%, TT:33.7%), internal fat levels and waist/hip ratios (p > 0.05). Significance of association between FTO genotypes and total body fat (%) was retained after adjustment for BMI and gender as well. BMI, LAP, and BAI index values were not different between different genotypes in all individuals and different genders (p > 0.05).

Conclusion

Our study supports that the FTO rs9939609 polymorphism is associated with fat accumulation in the whole body without being associated with abdominal fat accumulation in Turkish adults.

The FTO rs9939609 "A" allele is associated with impaired fasting glucose and insulin resistance in Emirati population

BACKGROUND

Fat mass and obesity-associated protein gene variants have shown diverse influence on body weight and metabolism across different populations. Overweight, obesity and metabolic syndrome are multifactorial major health problems in the UAE and worldwide. Insulin resistance represents the link between overweight and development of metabolic syndrome and type 2 diabetes mellitus. We investigated two (FTO) variants in Emirati population, in relation to insulin resistance and different parameters of metabolic syndrome.

METHODS

We recruited 259 Emiratis through the UAE National Diabetes and Lifestyle Project. Ethical approval was obtained. Besides basic data collection, venous blood samples were collected. Fasting blood glucose, Lipid profile, and insulin levels were measured. Genotyping for (FTO) rs9939609 (A>T) and rs9930506 (G>A) were performed using real time-PCR. Insulin resistance were identified using HOMA2-IR calculation; with a cut-off point of 1.4 for female and 1.18 for male subjects.

RESULTS

The study included 259 Emiratis (age range 30-53 years, mean 41.76 years, 54.4% females), 24.5% are diabetic and 30.8% are hypertensive, with body mass index of 28.4 ± 5.9 and 28.7 ± 5.7 kg/m² in female and male subjects, respectively. Homozygous A of rs9939609 showed significantly higher fasting glucose compared to other genotypes (p = 0.04) with a trend of higher insulin level and HOMA-2IR. The A/A diabetic patients (n = 13) showed significantly higher insulin levels compared to other genotypes. G allele of rs9930506 showed a trend of higher fasting glucose and HOMA-2IR, but lower insulin level and HbA1c. No association of genotypes was detected with other components of metabolic syndrome.

CONCLUSION

There is an association of FTO rs9939609 A/A genotype and impaired fasting glucose and insulin resistance. Homozygous A genotype diabetic patients may be more vulnerable to blood glucose fluctuation. Focused genotyping can help the health care providers to identify high risk groups of both normal population and diabetic patients to intervene accordingly.

Effect of FTO rs9939609 variant on insulin resistance in obese female adolescents

OBJECTIVES

FTO rs9939609 variant has been shown to be associated with insulin resistance in Caucasian children. However, studies in Asia show inconsistent findings. We investigated the association between FTO rs9939609 polymorphisms and insulin resistance in obese female adolescents in Indonesia, a genetically distinct group within Asia.

RESULTS

A total of 78 obese female adolescents participated in this study. The risk allele (A) frequency of FTO rs9939609 variant in Indonesian obese female adolescence was 44.2%. The frequency of insulin resistance was higher in the subjects with AA (54.6%) or AT (59.6%) than the subject with TT genotype (50%), but did not statistically different (p = 0.81 and p = 0.47, respectively). The insulin resistance rate was also higher in the risk allele (A) than the non-risk allele (T) subjects (0.58 vs. 0.55), but did not statistically different (p = 0.75). There was no association between FTO rs9939609 variant and body mass index, fasting glucose level, fasting insulin level, homeostatic model assessment of insulin resistance, and waist circumference (p > 0.05). In conclusion, FTO rs9939609 variant may not be associated with insulin resistance in Indonesian obese female adolescents. A multicenter study with a larger sample size is needed to clarify these findings.

Influence of FTO rs9939609 polymorphism on appetite, ghrelin, leptin, IL6, TNFα levels, and food intake of women with morbid obesity

BACKGROUND

The fat mass and obesity-related (FTO) gene has a strong relationship with obesity, extreme obesity and inflammatory state, and may also be associated with food intake regulation.

OBJECTIVE

The aim of the present study was to evaluate the influence of the rs9939609 single-nucleotide polymorphism of the FTO gene on appetite, ghrelin, leptin, interleukin 6 (IL6), tumor necrosis factor α (TNFα) levels and food intake of morbidly obese women.

MATERIALS AND METHODS

The study comprised 70 women, aged between 20 and 48 years, from Rio de Janeiro, Brazil. The participants were selected according to the body mass index between 40 and 60 kg/m². Anthropometric and biochemical data were measured during fasting. Hormones and inflammatory data were measured before and after the participants ate an isocaloric meal. Dietary records were calculated and analyzed using a nutritional assessment program. Visual analog scales were used for behaviors of the sensations of appetite and food preferences. The FTO rs9939609 variant was genotyped using real-time polymerase chain reaction.

RESULTS

Participants with the AA genotype had lower values of ghrelin and IL6 and higher values of leptin than those with TT and TA in the postprandial period. Comparing the plasma concentrations of ghrelin, insulin, IL6 and TNFα intragenotypes, it was observed that those with TT had decreased leptin and increased IL6 at the postprandial period. Subjects with TA showed increased postprandial IL6, and those with AA had decreased postprandial ghrelin. There was no difference in TNFα intra- and intergenotypes. The postprandial sensations of hunger were lower in AA than those with TT. There were differences between genotypes regarding ingested grams of protein by weight, cholesterol, B3, B5, B6 and B12 vitamins, and selenium potassium and sodium minerals.

CONCLUSION

These findings suggest that genetics may exert an influence on physiologic factors and might alter eating behavior.

Plasma stearoyl-CoA desaturase activity indices and bile acid concentrations after a low-fat meal: association with a genetic variant in the FTO gene

PURPOSE

Dietary macronutrient composition, stearoyl-CoA desaturase (SCD) activity indices, and primary bile acid (BA) concentrations are among the factors that have been associated with lipid metabolism and contributed to obesity. We investigated the association between the polymorphic expression of the fat mass and obesity-associated (FTO) gene and its relationship with SCD activity indices and primary BA concentrations after a low-fat meal.

SUBJECTS AND METHODS

Blood plasma samples were collected from 56 young (20-36 years) healthy subjects with different rs9939609 FTO genotypes. Fasting and post-meal (2 hours after a low-fat breakfast) blood samples were collected on the subsequent morning for the analysis of DNA methylation, SCD activity indices (product-to-precursor fatty acid ratios; 16:1n-7/16:0 and 18:1n-9/18:0), and chenodeoxycholic acid (CDCA) and cholic acid (CA) concentrations. Expression of lipogenic genes was investigated post-meal to assess the relationship between the CDCA and CA concentrations and mRNA levels of lipogenic genes.

RESULTS

The FTO AA (obesity risk) genotype group (n=18) had higher (P<0.05) post-meal SCD-16 activity index than the FTO TT (wild type) genotype group (n=26). In both the FTO TT (n=16) and AA (n=8) genotype groups, the post-meal concentrations of CDCA and CA were lower (P<0.05) compared with the fasted state. No difference in BA concentrations between the FTO TT and AA genotype groups in both meal states was observed. After adjusting for the body mass index, the highest 50% post-meal concentrations of CA were inversely (P=0.010) correlated with the level of mRNA SCD expression.

CONCLUSION

FTO AA carriers may be at a higher risk for obesity through higher SCD activity in a low-fat diet environment. This effect may be partly pronounced by very low CA concentrations.

Meta-analysis indicates that SNP rs9939609 within FTO is not associated with major depressive disorder (MDD) in Asian population

BACKGROUND

Major depressive disorder (MDD) is one of the most prevalent psychiatric illnesses with heritability of up to 38%. The fat mass- and obesity-associated (FTO) gene, in particular the single nucleotide polymorphism (SNP) rs9939609, has been identified as a genetic risk loci associated with MDD. However, most prior studies have involved European and American populations. Whether rs9939609 is an true risk SNP for MDD in Asian populations remains inconclusive.

METHODS

In the present study, we conducted a meta-analysis of the association between rs9939609 and MDD in Asian populations by combining 5 available case-control samples totaling 6531 cases and 12,359 controls.

RESULTS

Our meta-analysis suggests that rs9939609 is not a risk SNP for MDD in Asian populations by fixed effect model (Z=1.04, P=0.30, OR=0.96, 95% CI=0.90-1.03).

LIMITATIONS

The age distribution and gender ratios were not matched well in the combined samples of cases and controls. Publication bias might be also considered with only a relatively small number of association studies of FTO rs9939609 with MDD in Asian populations.

CONCLUSIONS

The absence of association of rs9939609 with MDD in our Asian populations suggests a potential genetic heterogeneity in the susceptibility of MDD on this locus.

Association between FTO gene polymorphism (rs9939609 T/A) and cancer risk: a meta-analysis

Obesity is a risk factor of cancer. Several genes have been found to play an important role in aetiology of obesity and tumourigenesis. Recently, some studies suggested that rs9939609 polymorphism might be significantly associated with cancer risk, while the results of some other studies were controversial. Databases with time limitation from January 1984 to April 2015 were searched. The pooled odds ratio (OR) with 95% confidence interval was calculated to assess the associations, and subgroup meta-analyses were performed according to the type of cancer and ethnicity of the study populations. Overall, the significant association between rs9939609 polymorphism and cancer risk was found in homozygote model and recessive model. As to subgroup classified by cancer type, there was significant association in endometrial cancer and pancreatic cancer, while no statistical significance was detected in other kind of cancers. Besides, in the subgroup analysis of ethnicity, our results indicated that rs9939609 polymorphism was significantly associated with cancer risk in Asians. The rs9939609 polymorphism may be involved the susceptibility of endometrial cancer and pancreatic cancer, especially in Asian populations. Thus, rs9939609 may be a potential biomarker in early diagnosis or gene therapy target of endometrial cancer and pancreatic cancer.

Differences in body mass index according to fat mass- and obesity-associated (FTO) genotype in Mexican patients with bipolar disorder

OBJECTIVES

The prevalence of obesity has dramatically increased in many countries and it is particularly high in patients with bipolar disorder (BD). A region in the first intron of the fat mass- and obesity-associated (FTO) gene, encompassing markers rs9939973, rs8050136, and rs9939609, has been consistently associated with obesity and body mass index (BMI) in different populations. We sought to determine whether FTO is associated with BMI and/or obesity in patients with BD.

METHODS

The sample included 129 Mexican Mestizo patients with bipolar I or bipolar II disorder. After obtaining informed consent, participants were evaluated with the Structured Clinical Interview for DSM-IV Axis I Disorders and weight, height, and body measurements were recorded. DNA was extracted from a 5-mL blood sample and real-time polymerase chain reaction was performed. The results were analyzed with Haploview v4.2 and SPSS v21.

RESULTS

Differences in mean BMI were explained by rs8050136 and rs9939609 genotypes, especially by comparing non-carriers and carriers of two copies of the risk allele (Tukey's p ≤ 0.019), with a mean difference in BMI as high as 7.81 kg/m(2) . Differences in BMI were also explained by the interaction of the genotype (rs8050136 and/or rs9939609), the use of second-generation antipsychotics, and the use of mood stabilizers (p ≤ 0.41). Obesity was also associated with these two markers when patients with and without obesity were compared.

CONCLUSIONS

In patients with BD, differences in BMI may be affected by the presence of FTO risk alleles, especially in homozygous individuals for these variants. Besides evaluating the possible metabolic effects of certain antipsychotics or mood stabilizers, it is important to evaluate the role of other factors such as FTO risk alleles.

The study of the rs9939609 FTO gene polymorphism in association with obesity and the management of obesity in a Romanian cohort

The incidence of obesity especially in Romanian population is presently escalating as a major nutrition and health problem. Clinicians aided by scientists are engaged in research approaches that include heredity aspects linked with behavior, education, applied nutrition studies and clinical therapies in order to prevent, control and reverse obesity. The common goal is to identify areas of basic and clinical research to understand aspects of human biology that may be considered as obesogenic. Regarding these approaches, recent discoveries in genetics, epigenetics and functional genomics, based on advancing technologies, are tools employed to prevent and treat obesity. The purpose of this article is to present the current knowledge of key components of the FTO gene role in the obesogenic system that links genetic, epigenetic and environmental, lifestyle/ diet nutritional and behavioral components and to describe the results obtained by genotyping and interviewing relevant selected groups of Romanian population. FTO rs9939609 genotyping was performed on a Romanian study group of 53 subjects (30 obese, 23 normal). Results have been analyzed in association with obesity parameters and comorbidities in order to identify this polymorphism's effect on body mass in our Caucasian cohort. At the same time, personal history of the subjects in correlation with the FTO genotypes provided important information on the FTO gene's influence on the feeding behavior and food selection of these individuals. In conclusion, the FTO rs9939609 polymorphism has been identified as a common gene variant in our Romanian Caucasian cohort, proving a high association with all the parameters of obesity and obesity comorbidities. The adherence to a Mediterranean diet is benefic for subjects with genetic predisposition for this disorder as long as it is kept for a long period of time along with sustained physical exercise. Association studies are an extremely important tool in understanding the hunger-satiety pathway, providing information on the relation between obesity-related genes, gene expression and behavior.

Effect of FTO Gene and Physical Activity Interaction on Trunk Fat Percentage Among the Newfoundland Population

OBJECTIVE

To explore the effect of FTO gene and physical activity interaction on trunk fat percentage.

DESIGN AND METHODS

Subjects are 3,004 individuals from Newfoundland and Labrador whose trunk fat percentage and physical activity were recorded, and who were genotyped for 11 single-nucleotide polymorphisms (SNPs) in the FTO gene. Subjects were stratified by gender. Multiple tests and multiple regressions were used to analyze the effects of physical activity, variants of FTO, age, and their interactions on trunk fat percentage. Dietary information and other environmental factors were not considered.

RESULTS

Higher levels of physical activity tend to reduce trunk fat percentage in all individuals. Furthermore, in males, rs9939609 and rs1421085 were significant (α = 0.05) in explaining central body fat, but no SNPs were significant in females. For highly active males, trunk fat percentage varied significantly between variants of rs9939609 and rs1421085, but there is no significant effect among individuals with low activity. The other SNPs examined were not significant in explaining trunk fat percentage.

CONCLUSIONS

Homozygous male carriers of non-obesity risk alleles at rs9939609 and rs1421085 will have significant reduction in central body fat from physical activity in contrast to homozygous males of the obesity-risk alleles. The additive effect of these SNPs is found in males with high physical activity only.

Association of FTO and PPARG polymorphisms with obesity in Portuguese women

PURPOSE

We evaluated the association between risk of obesity in the Portuguese population and two obesity-related single-nucleotide gene polymorphisms: fat-mass and obesity-associated (FTO) rs9939609 and peroxisome proliferator-activated receptor gamma (PPARG) rs1801282.

PATIENTS AND METHODS

A total of 194 Portuguese premenopausal female Caucasians aged between 18 and 50 years (95 with body mass index [BMI] ≥30 g/m(2), 99 controls with BMI 18.5-24.9 kg/m(2)) participated in this study. The association of the single-nucleotide polymorphisms with obesity was determined by odds ratio calculation with 95% confidence intervals.

RESULTS

Significant differences in allelic expression of FTO rs9939609 (P<0.05) were found between control and case groups, indicating a 2.5-higher risk for obesity in the presence of both risk alleles when comparing the control group with the entire obese group. A fourfold-higher risk was found for subjects with class III obesity compared to those with classes I and II. No significant differences in BMI were found between the control and case groups for PPARG rs1801282 (P>0.05).

CONCLUSION

For the first time, a study involving an adult Portuguese population shows that individuals harboring both risk alleles in the FTO gene locus are at higher risk for obesity, which is in agreement to what has been reported for other European populations.