Association of the FTO gene variant (rs9939609) with cardiovascular disease in men with abnormal glucose metabolism--the Finnish Diabetes Prevention Study

Sex and Race Differences in Obesity-Related Genetic Susceptibility and Risk of Cardiometabolic Disease in Older US Adults

Importance

The fat mass and obesity-associated gene (FTO) is associated with obesity phenotypes, but the association is inconsistent across populations. Within-population differences may explain some of the variability observed.

Objective

To investigate sex differences in the association between FTO single-nucleotide variants (SNVs) and obesity traits among self-identified non-Hispanic Black and non-Hispanic White US adults, to examine whether the SNVs were associated with cardiometabolic diseases, and to evaluate whether obesity mediated the association between FTO SNVs and cardiometabolic diseases.

Design, Setting, and Participants

This cross-sectional study used data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a US population-based cohort study with available genetic data (assayed in 2018) and phenotypic data at baseline (enrolled 2003-2007). Participants were aged 45 to 98 years at baseline. Data were analyzed from October 2021 to October 2022.

Exposures

Eleven SNVs in the FTO gene present among both Black and White participants.

Main Outcomes and Measures

Objectively measured obesity indicators (body mass index and waist-to-height ratio), objectively measured and/or self-reported cardiometabolic diseases (hypertension, stroke history, heart disease, and diabetes), and self-reported social-economic and psychosocial status.

Results

A total of 10 447 participants (mean [SD] age, 64.4 [9.7] years; 5276 [55.8%] women; 8743 [83.7%] Black and 1704 [16.3%] White) were included. In the White group, 11 FTO SNVs were significantly associated with obesity, hypertension, and diabetes using linear models (eg, body mass index: β = 0.536; 95% CI, 0.197-0.875), but none of the FTO SNVs were associated with obesity traits in the Black group. White males had a higher risk of obesity while White females had a higher risk of hypertension and diabetes. However, 1 FTO SNV (rs1121980) was associated with a direct increase in the risk of heart disease in Black participants not mediated by obesity (c' = 0.145 [SE, 0.0517]; P = .01).

Conclusions and Relevance

In this cross-sectional study of obesity phenotypes and their association with cardiometabolic diseases, the tested FTO SNVs reflected sex differences in White participants. Different patterns of associations were observed among self-identified Black participants. Therefore, these results could inform future work discovering risk alleles or risk scores unique to Black individuals or further investigating genetic risk in all US residents.

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].

The Interaction of Dietary Patterns and Genetic Variants on the Risk of Cardiovascular Diseases in Chinese Patients with Type 2 Diabetes

SCOPE

Diabetes is an important risk factor for cardiovascular disease (CVD), which in turn is the most common and serious complication of diabetes. This study analyzes dietary patterns and single nucleotide polymorphisms (SNPs) in 543 diabetes patients with new-onset cardiovascular events and 461 diabetic patients without.

METHODS AND RESULTS

SNPs are determined and analyzed using real time PCR and gene chip method. Factor analysis and logistic regression are used to determine dietary patterns and evaluate the level of associations and interaction effects, respectively. The legumes and edible fungi pattern and vegetable pattern show a significant negative correlation with complication risk. ADIPOQ rs37563 and legumes and edible fungi pattern have a significant interactive effect on disease, and patients with a high score of C polymorphism genotype (GC + CC) have a lower risk of disease. 5-10-Methylenetetrahydrofolate reductase (MTHFR) rs1801131 and vegetable pattern have a borderline interaction effect on disease, and those patients with TT genotype have a lower risk of disease.

CONCLUSION

These findings provide new insights into the role of the interactive protection of dietary patterns and SNPs. And participants with specific alleles show a lower risk of cardiovascular complications.

FTO Gene Polymorphisms and Their Roles in Acromegaly

The major causes of both morbidity and mortality in patients with acromegaly are cardiovascular diseases (CVDs). The polymorphisms of the fat mass and obesity-associated gene (FTO) are associated with obesity, as well as with an increased risk of CVDs. The aim of the study was to determine the relationship of risk alleles of four FTO gene polymorphisms with selected parameters of lipid and glucose metabolism as well as with IGF-1 and GH levels in the group of patients with acromegaly compared to the control group. The study group consisted of 104 patients with acromegaly and 64 healthy subjects constituting the control group. In the whole acromegaly group, the data reveal that the homozygous for risk allele carriers (rs1421085, rs9930506, rs9939609) as well as carriers of only one risk allele have lower IGF-1 concentrations. In the well-controlled acromegaly group, the homozygous for three risk allele carriers of FTO gene polymorphisms have lower HDL cholesterol concentration (rs1121980, rs1421085, rs993609). In the cured acromegaly group, homozygous risk allele carriers rs9930506 tend to have higher levels of total cholesterol and LDL cholesterol. These associations are not observed in the control group. Conclusion: there is an association between FTO gene polymorphisms and the metabolism of lipids, suggesting that the FTO gene may be associated with higher CVD risk in patients with acromegaly. In addition, there is an association between FTO gene polymorphisms and IGF-1, implying that FTO gene may influence/modify IGF-1 synthesis. Further investigation on a larger scale is required to provide more precise evidence.

Emerging Role and Mechanism of the FTO Gene in Cardiovascular Diseases

The fat mass and obesity-associated (FTO) gene was the first obesity-susceptibility gene identified through a genome-wide association study (GWAS). A growing number of studies have suggested that genetic variants of FTO are strongly associated with the risk of cardiovascular diseases, including hypertension and acute coronary syndrome. In addition, FTO was also the first N⁶-methyladenosine (m6A) demethylase, suggesting the reversible nature of m6A modification. m6A is dynamically deposited, removed, and recognized by m6A methylases, demethylases, and m6A binding proteins, respectively. By catalyzing m6A demethylation on mRNA, FTO may participate in various biological processes by modulating RNA function. Recent studies demonstrated that FTO plays a pivotal role in the initiation and progression of cardiovascular diseases such as myocardial fibrosis, heart failure, and atherosclerosis and may hold promise as a potential therapeutic target for treating or preventing a variety of cardiovascular diseases. Here, we review the association between FTO genetic variants and cardiovascular disease risk, summarize the role of FTO as an m6A demethylase in cardiovascular disorders, and discuss future research directions and possible clinical implications.

Fat mass and obesity-associated gene expression and disease severity in type 2 diabetes mellitus

Obesity and visceral adiposity are major risk factors for type 2 diabetes mellitus (T2DM). The fat mass and obesity-associated (FTO) gene is associated with increased risk of obesity and T2DM. The aim of this work was to study the association between FTO gene expression and serum FTO protein level with disease severity in T2DM patients.

PATIENTS AND METHODS

One hundred T2DM patients were divided into two equal groups according to diabetes control and complications and fifty healthy controls were included in this study. FTO messenger ribonucleic acid (mRNA) expression level was analyzed by Real time polymerase chain reaction (PCR) technique and serum level of FTO protein was measured by ELISA.

RESULTS

FTO gene expression and FTO protein levels were increased in the two T2DM groups compared to the control group with significant further increases in patients with severe disease. FTO gene expression and FTO protein levels were positively correlated with obesity, insulin resistance and blood glucose indices as well as the presence of diabetic complications. Regression analyses showed that FTO gene expression and FTO protein levels were risk factors for T2DM severity.

CONCLUSIONS

Increased FTO gene expression and its serum protein levels are associated with increased T2DM severity.

Association of rs9939609-FTO with metabolic syndrome components among women from Mayan communities of Chiapas, Mexico

Background

Metabolic syndrome (MetS) is a complex cluster of risk factors, considered as a polygenic and multifactorial entity. The objective of this study was to determine the association of rs9939609-FTO polymorphism and MetS components in adult women of Mayan communities of Chiapas.

Methods

In a cross-sectional study, sociodemographic, anthropometric, clinical, and biochemical data were obtained from 291 adult women from three regions of Chiapas, Mexico. The prevalence of MetS and the allele and genotype frequencies of the rs9939609-FTO were estimated. Multivariate logistic regression models were used to assess the association of the single nucleotide polymorphism (SNP) with each of the MetS components.

Results

The MetS prevalence was 60%. We found a statistically significant association between rs9939609-FTO and hyperglycemia in the dominant model (OR 2.6; 95% CI 1.3–5.3; p = 0.007).

Conclusions

Women from Mayan communities of Chiapas presented a high prevalence of MetS and a relevant association of the FTO variant with hyperglycemia. This is the first study carried out in these Mayan indigenous communities from Chiapas.

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.

FTO regulates ocular angiogenesis via m6A-YTHDF2-dependent mechanism

Pathological ocular angiogenesis commonly results in visual impairment or even blindness. Unveiling the mechanisms of pathological angiogenesis is critical to identify the regulators and develop effective targeted therapies. Here, we used corneal neovascularization (CNV) model to investigate the mechanism of pathological ocular angiogenesis. We show that N⁶-methyladenosine (m⁶A) mRNA demethylation mediated by fat mass- and obesity-associated protein (FTO) could regulate endothelial cell (EC) function and pathological angiogenesis during CNV. FTO levels are increased in neovascularized corneas and ECs under pathological conditions. In vitro silencing of FTO in ECs results in reduced cellular proliferation, migration, and tube formation under both basal and pathological conditions. Furthermore, FTO silencing attenuates suture-induced CNV in vivo. Mechanically, FTO silencing in ECs could increase m⁶A methylation levels in critical pro-angiogenic genes, such as FAK, leading to decreased RNA stability and increased RNA decay through m⁶A reader YTHDF2. Our study demonstrates that FTO regulates pathological ocular angiogenesis by controlling EC function in an m⁶A-YTHDF2-dependent manner.

Biochemistry, hormones and adipocytokines in prepubertal children born with IUGR evoke metabolic, hepatic and renal derangements

Children born with IUGR develop features of the metabolic syndrome and exhibit deranged markers of hepatorenal physiology. Metabolic and hepatorenal biochemistry and the rs9939609 FTO polymorphism were investigated in prepubertal children born with IUGR. Ninety-eight prepubertal children (46 IUGR and 52 AGA), subdivided in <5 years and >5 years old groups were included. Anthropometry; creatinine, eGFR, urea, AST, ALT, triglycerides, uric acid, total cholesterol, HDL-c, LDL-c, glucose, C-peptide, insulin and glucagon z-scores; HOMA-IR; leptin and adiponectin concentrations; rs9939609 FTO polymorphism frequency were measured. In males, weight and ALT were higher and adiponectin was lower, in IUGR < 5 years; C-peptide, insulin and leptin were higher in IUGR > 5 years; C-peptide was higher in all IUGR, than the respective AGA. In females, creatinine and triglycerides were higher in IUGR < 5 years old; creatinine was higher and eGFR was lower in all IUGR, than the respective AGA. In males and females, creatinine was higher in all IUGR, than the respective AGA; C-peptide, insulin and HOMA-IR were lower, and AST was higher in IUGR < 5 than in IUGR > 5 years old. FTO rs9939609 frequency did not differ between IUGR and AGA. In conclusion prepubertal males born with IUGR increased weight, insulin and leptin and decreased adiponectin, as compared to males born AGA, emerge as early metabolic syndrome characteristics. The concentrations of these hormones do not differ between prepubertal males and females born with IUGR. Weight control, healthy nutrition and physical exercise should be recommended to these children. The deranged renal (particularly evident in females below the age of 5) and liver biochemistry in prepubertal children born with IUGR suggests that hepatorenal derangements might commence in utero. Regular checkup of biochemical and lipid profile is recommended for all children born with IUGR.

Association between FTO gene polymorphisms and HDL cholesterol concentration may cause higher risk of cardiovascular disease in patients with acromegaly

INTRODUCTION

Cardiovascular diseases are main cause of morbidity and mortality in acromegaly. Polymorphisms of FTO gene are associated with obesity and increased risk of CVD (independently of BMI). Aim of this study was to investigate the allele frequencies of two FTO gene polymorphisms: rs9939609 and rs9930506 in patients with acromegaly and to examine the association of FTO gene polymorphisms with BMI and selected metabolic parameters.

MATERIALS AND METHODS

Identification of two single nucleotide polymorphisms of FTO gene was carried out in 51 patients with acromegaly using the minisequencing method.

RESULTS

The risk-allele frequencies of rs9939609 and rs9930506 polymorphisms were 0.471 and 0.529, respectively and they were higher than in general European population. There is no association of FTO gene polymorphisms with BMI, glucose, total cholesterol, LDL cholesterol and triglyceride. The risk alleles were associated with decreased HDL cholesterol concentration. Homozygotes for the rs9939609-risk allele had 1.25-fold lower HDL cholesterol concentration than carriers of the TT genotype (p = 0.0024). The estimated average decrease in HDL cholesterol concentration per risk allele for rs9930506 was 11.2%. Nevertheless, statistically significant differences were observed only between AG versus GG and AA versus GG genotypes. Homozygotes for the rs9930506-risk allele had 1.27-fold lower HDL cholesterol concentration than carriers of the AA genotype (p = 0.007).

CONCLUSION

The risk-allele frequencies of studied polymorphisms in acromegaly were higher than in general European population. There is an association between FTO gene polymorphisms and HDL cholesterol concentration, suggesting FTO gene polymorphisms may be associated with higher CVD risk in patients with acromegaly.

Blood-Based DNA Methylation Biomarkers for Type 2 Diabetes: Potential for Clinical Applications

Type 2 diabetes (T2D) is a leading cause of death and disability worldwide. It is a chronic metabolic disorder that develops due to an interplay of genetic, lifestyle, and environmental factors. The biological onset of the disease occurs long before clinical symptoms develop, thus the search for early diagnostic and prognostic biomarkers, which could facilitate intervention strategies to prevent or delay disease progression, has increased considerably in recent years. Epigenetic modifications represent important links between genetic, environmental and lifestyle cues and increasing evidence implicate altered epigenetic marks such as DNA methylation, the most characterized and widely studied epigenetic mechanism, in the pathogenesis of T2D. This review provides an update of the current status of DNA methylation as a biomarker for T2D. Four databases, Scopus, Pubmed, Cochrane Central, and Google Scholar were searched for studies investigating DNA methylation in blood. Thirty-seven studies were identified, and are summarized with respect to population characteristics, biological source, and method of DNA methylation quantification (global, candidate gene or genome-wide). We highlight that differential methylation of the TCF7L2, KCNQ1, ABCG1, TXNIP, PHOSPHO1, SREBF1, SLC30A8, and FTO genes in blood are reproducibly associated with T2D in different population groups. These genes should be prioritized and replicated in longitudinal studies across more populations in future studies. Finally, we discuss the limitations faced by DNA methylation studies, which include including interpatient variability, cellular heterogeneity, and lack of accounting for study confounders. These limitations and challenges must be overcome before the implementation of blood-based DNA methylation biomarkers into a clinical setting. We emphasize the need for longitudinal prospective studies to support the robustness of the current findings of this review.

The FTO variant is associated with chronic complications of diabetes mellitus in Czech population

BACKGROUND

Genome-wide association studies have resulted in the identification of the FTO gene as an important genetic determinant of diabetes mellitus. The aim of this study was to confirm the role of this gene in the development of DM in the Czech-Slavonic population and to analyse whether this gene is associated with common DM complications.

METHODS

Two groups of patients (814 with T1DM and 848 with T2DM) and a group of healthy controls (2339 individuals) - both of Czech origin - were genotyped for the FTO rs17817449 SNP. ANOVA and logistic regression were used for the statistical evaluations.

RESULTS

The frequency of the GG genotype was significantly higher in T2DM (25.4% vs. 16.7%, P<0.0005) but not in T1DM patients (19.3% vs. 16.7%, P=0.20) than in controls. The increased risk of development of diabetic nephropathy was observed both for T1DM patients (GG vs. TT homozygotes, P<0.01) and T2DM patients (G carriers vs. TT homozygotes, P<0.05). FTO genotype predicted the development of diabetic neuropathy (GG vs. TT comparison; P<0.01) in the T2DM patients only. No association between FTO genotype and development of retinopathy was detected. All presented values are after adjustment for age, sex, BMI and duration of diabetes.

CONCLUSIONS

We confirm the association between the FTO rs17817449 SNP and susceptibility to T2DM in the Czech-Slavonic population. The same variant is associated with a spectrum of chronic complications in both types of diabetes.

The (FTO) gene polymorphism is associated with metabolic syndrome risk in Egyptian females: a case- control study

Background

Variations within fat mass and obesity associated (FTO) gene had crosstalk with obesity risk in European and some Asian populations. This study was designed to investigate FTO rs9939609 association with metabolic syndrome (MetS) as well as biochemical parameters as plasma glucose, serum triacylglycerol (TAG), total cholesterol (TC) and transaminases enzymes in Arab female population from Egypt.

Methods

In order to achieve that, FTO gene rs9939609 (A < T) was genotyped using TaqMan SNP Genotyping Assay in a total of 197 females which were enrolled in this study. Fasting levels of serum insulin, lipid profile and plasma glucose, in addition to liver transaminases were measured. The association between the genotype distribution and MetS risk was evaluated using Chi-square and logistic regression tests in a case-control design under different genetic models.

Results

The association of genotype distribution with MetS was significant (χ2 = 8.6/P = 0.014) with an increased odds ratio under dominant model (OR = 1.97, P = 0.029 and 95%C.I = 1.07–3.6) and recessive model (OR = 2.95, P = 0.017 and 95%C.I = 1.22–7.22). Moreover, (AA) subjects showed significant lower HDL-C levels (P = 0.009) when compared to (TT) ones. In addition, interestingly subjects with (AA) genotype have significantly higher ALT levels (P = 0.02) that remained significant after correction of major confounders as body mass index and serum triacylglycerols but not after conservative Bonferroni adjustment.

Conclusions

The present study shows for first time that FTO gene rs9939609 is genetic risk factor for metabolic syndrome in Egyptian population which may help in understanding the biology of this complex syndrome and highlighted that this association may be through HDL-C component. The association of this genetic polymorphism with ALT levels needs to be studied in other populations with larger sample size.

Molecular Analysis of a Genetic Variants Panel Related to Nutrients and Metabolism: Association with Susceptibility to Gestational Diabetes and Cardiometabolic Risk in Affected Women

Gestational diabetes mellitus (GDM) is the most frequent metabolic disorder in pregnancy. Women with a GDM history are at increased risk of developing diabetes and cardiovascular diseases. Studies have demonstrated a significant correlation between several genes involved in the metabolic pathway of insulin and environmental factors. The aim of this study was to investigate the relationship between clinical parameters in GDM and variants in genes involved with nutrients and metabolism. Several variants PPARG2 rs1801282 (C>G); PPARGC1A rs8192678 (C>T); TCF7L2 rs7903146 (C>T); LDLR rs2228671 (C>T); MTHFR rs1801133 (C>T); APOA5 rs662799 (T>C); GCKR rs1260326 (C>T); FTO rs9939609 (T>A); MC4R rs17782313 (T>C) were genotyped in 168 pregnant Caucasian women with or without GDM by High Resolution Melting (HRM) analysis. A significant correlation was observed between TT genotype of TCF7L2 gene and increased risk of GDM (OR 5.4 [95% CI 1.5-19.3]). Moreover, a significant correlation was observed between lipid parameters and genetic variations in additional genes, namely, PPARG2 [p = 0,02], APOA5 [p = 0,02], MC4R [p = 0,03], LDLR [p = 0,01], and FTO [p = 0,02]. Our findings support the association between TCF7L2 rs7903146 variant and an increased GDM risk. Results about the investigated genetic variants provide important information about cardiometabolic risk in GDM and help to plan future prevention studies.

Role of a common variant of Fat Mass and Obesity associated (FTO) gene in obesity and coronary artery disease in subjects from Punjab, Pakistan: a case control study

BACKGROUND

The FTO gene has recently become one of the most extensively investigated genes associated with body mass and has been shown to play a role in cardiovascular diseases as well. The aim of the current study was to investigate the effect of a common variant of FTO gene, rs9939609 in obese and coronary heart disease (CHD) patients of Pakistan and investigate whether it has any influence on the serum biochemical parameters.

METHODS

A total of 970 samples (295 obese, 425 CHD and 250 controls) were genotyped using TaqMan allelic discrimination assay. Serum total cholesterol, HDL-C and triglycerides were measured using spectrophotometric methods. LDL-C was calculated by Friedwalds equation. Statistical analysis was done by SPSS version 22.

RESULTS

Results showed moderately high minor allele frequency (MAF) in obese and CHD cases as compared to controls (obese = 0.381 CAD = 0.361 and controls = 0.286). The variant was significantly associated with obesity and CAD (obesity odds ratio (OR) = 1.54, confidence interval (CI) = 1.07-2.21, p = 0.0009; CHD OR = 1.43, CI = 1.02-2.01, p = 0.004) in Pakistan. The risk allele did not show a significant association with any of the lipid trait tested (p > 0.05) but a strong association was observed with plasma glucose levels (obese p = 0.001, CAD p = 0.014, controls p = 0.019).

CONCLUSION

In conclusion, the variant was associated with obesity and CAD in the studied subjects and its possible effect may involve the blood sugar metabolism but not serum lipid chemistry.

Effects of a High-Protein/Low-Carbohydrate Diet versus a Standard Hypocaloric Diet on Weight and Cardiovascular Risk Factors: Role of a Genetic Variation in the rs9939609 FTO Gene Variant

BACKGROUND AND AIMS

The common polymorphism rs9939609 of the fat mass- and obesity-associated gene (FTO) has been linked to obesity. Our aim was to investigate its role in weight loss after the administration of a high-protein/low-carbohydrate diet compared to a standard hypocaloric diet (1,000 kcal/day).

METHODS

During 9 months, 195 patients were randomly allocated to a high-protein hypocaloric diet (HP diet) and a standard hypocaloric diet (S diet).

RESULTS

With the HP diet, BMI (-1.9 ± 1.2 vs. -2.10 ± 1.8; p < 0.05), weight (-6.5 ± 2.1 vs. -10.1 ± 4.1 kg; p < 0.05), fat mass (-3.9 ± 3.2 vs. -6.0 ± 3.4 kg; p < 0.05) and waist circumference (-5.7 ± 5.0 vs. -9.9 ± 5.5 cm; p < 0.05) decreased in both genotype groups (TT vs. AT + AA). With the S diet, BMI (-0.9 ± 1.1 vs. -1.8 ± 1.2; p < 0.05), weight (-3.2 ± 3.0 vs. -9.1 ± 3.6 kg; p < 0.05), fat mass (-3.0 ± 3.1 vs. -5.2 ± 3.1 kg; p < 0.05) and waist circumference (-3.1 ± 4.0 vs. -8.1 ± 4.9 cm; p < 0.05) decreased in both genotype groups. With the HP diet and in both genotype groups, glucose, insulin levels, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol, triglycerides and low-density lipoprotein (LDL) decreased. With the S diet, total cholesterol and LDL decreased.

CONCLUSION

Weight loss was better in A allele carriers than noncarriers, and metabolic improvement was better with the HP diet.

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.

Markers of cholesterol metabolism as biomarkers in predicting diabetes in the Finnish Diabetes Prevention Study

BACKGROUND AND AIMS

We examined the effect of serum markers of cholesterol synthesis and absorption on the incidence of type 2 diabetes (T2D) in the randomized Finnish Diabetes Prevention Study (DPS). We also explored a possible interaction of ABCG8 rs4299376 on sterol levels and lifestyle intervention.

METHODS AND RESULTS

We conducted a prospective cohort study including overweight, middle-aged people with impaired glucose tolerance at baseline who participated in the randomized DPS. The primary outcome of the DPS was the diagnosis of T2D based on repeated oral glucose tolerance tests (OGTTs). After active intervention (median of four years, 1994-2001), non-T2D participants were further followed until T2D diagnosis, dropout or the end of 2009. Of these, 340 participants who had β-sitosterol, campesterol, lathosterol and desmosterol measured by gas chromatography-mass spectrometry during the active four-year follow-up and who were not using cholesterol lowering medications were analysed. Surrogate indexes of insulin sensitivity (IS) and secretion were calculated from an OGTT. In adjusted models, plant sterols during the four-year follow-up were associated with lower T2D incidence during the extended eight-year follow-up (HR for 1-SD change in β-sitosterol and campesterol: 0.76 [0.63-0.92], and 0.81 [0.67-0.99], respectively). Lathosterol levels were associated with higher T2D incidence (HR: 1.35 [1.13-1.62]). These associations, though, were not independent of IS. There was an interaction between rs4299376 and study group on β-sitosterol (p = 0.001) and campesterol (p = 0.004) levels during the follow-up.

CONCLUSIONS

Markers of low absorption and high synthesis of cholesterol were associated with the risk of developing T2D, mostly ascribed to IS.

N6-adenosine methylation in MiRNAs

Methylation of N6-adenosine (m6A) has been observed in many different classes of RNA, but its prevalence in microRNAs (miRNAs) has not yet been studied. Here we show that a knockdown of the m6A demethylase FTO affects the steady-state levels of several miRNAs. Moreover, RNA immunoprecipitation with an anti-m6A-antibody followed by RNA-seq revealed that a significant fraction of miRNAs contains m6A. By motif searches we have discovered consensus sequences discriminating between methylated and unmethylated miRNAs. The epigenetic modification of an epigenetic modifier as described here adds a new layer to the complexity of the posttranscriptional regulation of gene expression.

The fat mass and obesity-associated (FTO) gene variant rs9939609 predicts long-term incidence of cardiovascular disease and related death independent of the traditional risk factors

OBJECTIVE AND METHODS

The impact of the rs9939609 FTO variant on cardiovascular events was investigated in the 19-year follow-up of subjects recruited to the OPERA study.

RESULTS

A total of 212 cardiovascular disease (CVD) and 152 coronary heart disease (CHD) events or deaths occurred during follow-up. The logistic regression analysis revealed that among the AA genotype the incidence of CHD (OR 1.905; 95% CI 1.250-2.903, p = 0.001) and CVD (OR 1.849; 1.265-2.702, p = 0.003) events or death was significantly higher when adjusted for age, sex, and study group. After further adjustment with BMI, smoking status, systolic blood pressure, and low-density lipoprotein cholesterol, the higher incidence of CHD and CVD events or death among subjects with the AA genotype remained significant (OR 1.895; p = 0.002 and p = 0.004, respectively). In Cox regression analysis, the AA genotype displayed a higher rate of CVD and CHD death when the model was adjusted for sex, age, and study group (p = 0.006 and p = 0.046). FTO rs9939609 AA genotype improved the C-index of the final predictive model from 0.709 to 0.715. In reclassification analyses, the integrated discrimination index was significant 0.011 (p = 0.010).

CONCLUSION

The AA genotype of FTO rs9939609 seems to be associated with a higher risk of CVD, and this phenomenon seems to be independent of the traditional risk factors for atherosclerosis.

Structure and function of dioxygenases in histone demethylation and DNA/RNA demethylation

Iron(II) and 2-oxoglutarate (2OG)-dependent dioxygenases involved in histone and DNA/RNA demethylation convert the cosubstrate 2OG and oxygen to succinate and carbon dioxide, resulting in hydroxylation of the methyl group of the substrates and subsequent demethylation. Recent evidence has shown that these 2OG dioxygenases play vital roles in a variety of biological processes, including transcriptional regulation and gene expression. In this review, the structure and function of these dioxygenases in histone and nucleic acid demethylation will be discussed. Given the important roles of these 2OG dioxygenases, detailed analysis and comparison of the 2OG dioxygenases will guide the design of target-specific small-molecule chemical probes and inhibitors.

FTO Genotype, Physical Activity, and Coronary Heart Disease Risk in Swedish Men and Women

Background—

Variants in the fat mass– and obesity-associated gene ( FTO ) predisposing to obesity and diabetes mellitus have also been associated with cardiovascular disease. Physical activity has been suggested to attenuate the FTO effect on obesity, but it is unknown whether this is also true for cardiovascular disease. Therefore, we explored whether physical activity modifies the FTO association with coronary heart disease (CHD).

Methods and Results—

FTO rs9939609 (T>A) polymorphism was genotyped in 2 Swedish population–based case–control studies with 1743 CHD cases and 4402 population controls (25–74 years of age; 41% women). Leisure time physical activity was assessed by questionnaires, and 3 levels were defined: low, medium, and high. Overall, carriers of the FTO A allele had an increased risk of CHD (odds ratio, 1.20; 95% confidence interval, 1.06–1.37) adjusted for age, sex, study, and body mass index. Although A-allele carriers with low physical activity had the highest CHD risk (odds ratio, 3.30; 95% confidence interval, 2.44–4.46) compared with those with TT genotype and high activity, the effects of FTO genotype and physical activity on CHD risk were approximately additive, indicating the absence of additive interaction. The stratum-specific relative risks of CHD from the A allele in subjects with low, medium, and high physical activity were odds ratio 1.11 (95% confidence interval, 0.77–1.60), 1.22 (1.04–1.44), and 1.38 (1.06–1.80), respectively, but the suggested multiplicative interaction was not significant.

Conclusions—

FTO rs9939609 A-allele carriers have an increased CHD risk, and the association is not counteracted by increased physical activity.

The FTO gene polymorphism (rs9939609) is associated with metabolic syndrome in morbidly obese subjects from southern Italy

Gene variants in MC4R, SIRT1 and FTO are associated with severe obesity and metabolic impairment in Caucasians. We investigated whether common variants in these genes are associated with metabolic syndrome (MetS) in a large group of morbidly obese young adults from southern Italy. One thousand morbidly obese subjects (62% women, mean body mass index 46.5 kg/m(2), mean age 32.6 years) whose families had lived in southern Italy for at least 2 generations were recruited. Single-nucleotide polymorphisms (SNPs) rs12970134, rs477181, rs502933 (MC4R locus), rs3818292, rs7069102, rs730821, rs2273773, rs12413112 (SIRT1 locus) and rs1421085, rs9939609, 9930506, 1121980 (FTO locus) were genotyped by Taqman assay; blood parameters were assayed by routine methods; the Fat Mass, Fat Free Mass, Respiratory Quotient, Basal Metabolic Rate (BMR) and waist circumference were also determined. Binomial logistic regression showed that the TA heterozygous genotype of SNP rs9939609 in the FTO gene was associated with the presence of MetS in our population [OR (95% CI): 2.53 (1.16-5.55)]. Furthermore, the FTO rs9939609 genotype accounted for 21.3% of the MetS phenotype together with total cholesterol, BMR and age. Our results extend the knowledge on genotype susceptibility for MetS in relation to a specific geographical area of residence.

The roles of Jumonji-type oxygenases in human disease

The iron- and 2-oxoglutarate-dependent oxygenases constitute a phylogenetically conserved class of enzymes that catalyze hydroxylation reactions in humans by acting on various types of substrates, including metabolic intermediates, amino acid residues in different proteins and various types of nucleic acids. The discovery of jumonji (Jmj), the founding member of a class of Jmj-type chromatin modifying enzymes and transcriptional regulators, has culminated in the discovery of several branches of histone lysine demethylases, with essential functions in regulating the epigenetic landscape of the chromatin environment. This work has now been considerably expanded into other aspects of epigenetic biology and includes the discovery of enzymatic steps required for methyl-cytosine demethylation as well as modification of RNA and ribosomal proteins. This overview aims to summarize the current knowledge on the human Jmj-type enzymes and their involvement in human pathological processes, including development, cancer, inflammation and metabolic diseases.

Influence of FTO variants on obesity, inflammation and cardiovascular disease risk biomarkers in Spanish children: a case-control multicentre study

Background

Variants in the FTO gene have been associated with obesity in children, but this association has not been shown with other biomarkers. We assessed the association of 52 FTO polymorphisms, spanning the whole gene, with obesity and estimated the influence of these polymorphisms on anthropometric, clinical and metabolic parameters as well as inflammation and cardiovascular disease (CVD) risk biomarkers among Spanish children.

Methods

A multicentre case–control study was conducted in 534 children (292 obese and 242 with normal-BMI). Anthropometric, clinical, metabolic, inflammation and CVD risk markers were compared using the Student’s t-test for unpaired samples. The genotype relative risk was assessed by comparing the obese and normal-BMI group, calculating the odds ratio. The association of each SNP with phenotypic parameters was analysed using either logistic or linear regression analysis.

Results

All anthropometric, clinical and metabolic factors as well as inflammatory and CVD risk biomarkers were higher in the obese than in the normal-BMI group, except adiponectin and HDL-c that were lower, and glucose, LDL-c, and metalloproteinase-9 that did not show difference. Four polymorphisms (rs9935401, rs9939609, rs9928094 and rs9930333) were positively associated with obesity and in linkage disequilibrium between each other; the haplotype including the risk alleles of these polymorphisms showed a high risk for obesity. The rs8061518 was negatively associated with obesity and the haplotype including this SNP and rs3826169, rs17818902 and rs7190053 showed a decreased risk for obesity. Additionally, the rs8061518 was associated with weight, diastolic blood pressure, insulin, homeostatic model assessment of insulin resistance, leptin, and active plasminogen inhibitor activator-1 after sex and age adjustment; however, after an additional BMI adjustment, this polymorphism remained associated only with leptin.

Conclusions

We validated the previous reported association of genetic variability in intron 1 of the FTO gene with the risk of obesity and found no association with other related traits in this region of the gene. We have observed strong statistical evidence for an association of rs8061518 in intron 3 of the gene with decreased risk of obesity and low concentration of leptin.

Methylation modifications in eukaryotic messenger RNA

RNA methylation modifications have been found for decades of years, which occur at different RNA types of numerous species, and their distribution is species-specific. However, people rarely know their biological functions. There are several identified methylation modifications in eukaryotic messenger RNA (mRNA), such as N(7)-methylguanosine (m(7)G) at the cap, N(6)-methyl-2'-O-methyladenosine (m(6)Am), 2'-O-methylation (Nm) within the cap and the internal positions, and internal N(6)-methyladenosine (m(6)A) and 5-methylcytosine (m(5)C). Among them, m(7)G cap was studied more clearly and found to have vital roles in several important mRNA processes like mRNA translation, stability and nuclear export. m(6)A as the most abundant modification in mRNA was found in the 1970s and has been proposed to function in mRNA splicing, translation, stability, transport and so on. m(6)A has been discovered as the first RNA reversible modification which is demethylated directly by human fat mass and obesity associated protein (FTO) and its homolog protein, alkylation repair homolog 5 (ALKBH5). FTO has a special demethylation mechanism that demethylases m(6)A to A through two over-oxidative intermediate states: N(6)-hydroxymethyladenosine (hm(6)A) and N(6)-formyladenosine (f(6)A). The two newly discovered m(6)A demethylases, FTO and ALKBH5, significantly control energy homeostasis and spermatogenesis, respectively, indicating that the dynamic and reversible m(6)A, analogous to DNA and histone modifications, plays broad roles in biological kingdoms and brings us an emerging field "RNA Epigenetics". 5-methylcytosine (5mC) as an epigenetic mark in DNA has been studied widely, but m(5)C in mRNA is seldom explored. The bisulfide sequencing showed m(5)C is another abundant modification in mRNA, suggesting that it might be another RNA epigenetic mark. This review focuses on the main methylation modifications in mRNA to describe their formation, distribution, function and demethylation from the current knowledge and to provide future perspectives on functional studies.

The FTO gene rs9939609 polymorphism predicts risk of cardiovascular disease: a systematic review and meta-analysis

Objective

Genome-wide association studies have shown that variance in the fat mass- and obesity- associated gene (FTO) is associated with risk of obesity in Europeans and Asians. Since obesity is associated with an increased risk of cardiovascular disease (CVD), several studies have investigated the association between variant in the FTO gene and CVD risk, with inconsistent results. In this study, we performed a meta-analysis to clarify the association of rs9939609 variant (or its proxies [r²>0.90]) in the FTO gene with CVD risk.

Methods

Published literature from PubMed and Embase was retrieved. Pooled odds ratios with 95% confidence intervals were calculated using the fixed- or random- effects model.

Results

A total of 10 studies (comprising 19,153 CVD cases and 103,720 controls) were included in the meta-analysis. The results indicated that the rs9939609 variant was significantly associated with CVD risk (odds ratio = 1.18, 95% confidence interval = 1.07–1.30, p = 0.001 [Z test], I² = 80.6%, p<0.001 [heterogeneity]), and there was an insignificant change after adjustment for body mass index (BMI) and other conventional CVD risk factors (odds ratio = 1.16, 95% confidence interval = 1.05–1.27, p = 0.003 [Z test], I² = 75.4%, p<0.001 [heterogeneity]).

Conclusions

The present meta-analysis confirmed the significant association of the rs9939609 variant in the FTO gene with CVD risk, which was independent of BMI and other conventional CVD risk factors.

Short term follow-up of prediabetics undergoing elective percutaneous coronary intervention

BACKGROUND

Epidemiologic evidence suggests that the complications of diabetes begin early in the progression from normal glucose tolerance to frank diabetes. Prediabetes is defined as people with impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), some of whom in fact already have the characteristic microvascular changes resulting from diabetes itself.

METHODS AND RESULTS

This study was conducted on 108 patients presenting to Ain Shams University Catheterization Laboratory for elective percutaneous coronary intervention using bare metal stents (48 diabetic patients, 30 pre-diabetic patients and 30 non-diabetic patients). All patients underwent bare metal stent deployment either preceded by balloon dilatation or not. Follow-up was done at three and six months for major adverse cardiac & cerebral events (cardiovascular death, acute coronary syndrome, cerebrovascular stroke, target vessel revascularization).

RESULTS

Our findings demonstrate that there was no statistically significant difference between patients of the three different study groups regarding composite end point of death, stroke, acute coronary syndrome and target vessel revascularization at three months follow-up (diabetics = 18.8%, pre-diabetics = 13.3%, non diabetics = 3.3%, p-value = 0.1), but there was a highly statistical difference between them regarding acute coronary syndrome (diabetics = 43%, pre-diabetics = 26%, non diabetics = 10%, p-value = 0.006) at six months follow-up.

CONCLUSION

Prediabetes, though not a disease entity by itself is associated with of risk for both macrovascular and increasingly, microvascular pathology. It is important to identify these conditions to prevent incident diabetes and to take measures to stop the vascular complications. Our study findings revealed that complications of diabetes may begin early as patients are suffering impaired glucose homeostasis, which warrants further evaluation in larger studies.

Reduced memory in fat mass and obesity-associated allele carriers among older adults with cardiovascular disease

BACKGROUND

Much attention has been paid to the prevalence and predisposition of the fat mass and obesity-associated (FTO) gene to obesity, although only a few studies have characterized the extent to which this affects cognitive function. This study examined differences between risk allele carriers (i.e. FTO-AC/AA) and non-carriers (i.e. FTO-CC) on indices of attention/executive function/psychomotor speed, memory, language, and visual-spatial ability in a sample of older patients with cardiovascular disease.

METHODS

We recruited 120 older adults from an outpatient cardiology clinic who underwent blood draw and completed neuropsychological testing. Participants were classified into two groups: one for those who were homozygous for the non-risk-conferring allele (i.e. FTO-CC) (n= 49) and the other for those who had at least one copy of the obesity risk-conferring A allele (i.e. FTO-AC/AA) (n= 71).

RESULTS

Mancova analyses adjusting for age and years of education revealed the FTO-AC/AA group performed significantly worse on indices of memory (λ= 0.94, F(2, 115) = 3.58, P= 0.03, partial η(2) = 0.06). Follow-up tests revealed a significant effect for the FTO-AC/AA group, relative to the non-carrier group, on encoding (i.e. California Verbal Learning Test Total Learning) and California Verbal Learning Test long-delay free recall (P < 0.05). No such differences between FTO carriers and non-carriers emerged on tests of attention/executive function/psychomotor speed, language, or visual-spatial ability (P > 0.05 for all).

CONCLUSIONS

These findings suggest that the FTO risk allele is associated with reduced memory performance, particularly on aspects of memory encoding and delayed recall. To elucidate underlying mechanisms, these findings will need to be replicated in larger samples that utilize neuroimaging.

FTO T/A and peroxisome proliferator-activated receptor-γ Pro12Ala polymorphisms but not ApoA1 -75 are associated with better response to lifestyle intervention in Brazilians at high cardiometabolic risk

BACKGROUND

The role of obesity-related polymorphisms on weight loss and inflammatory responses to interventions is unclear. We investigated associations of certain polymorphisms with response to a lifestyle intervention.

METHODS

This 9-month intervention on diet and physical activity included 180 Brazilians at high cardiometabolic risk, genotyped for the fat mass and obesity-associated (FTO) T/A, peroxisome proliferator-activated receptor-γ (PPARγ) Pro12Ala, and ApoA1 -75G/A polymorphisms. Changes in metabolic and inflammatory variables were analyzed according to these polymorphisms.

RESULTS

The intervention resulted in lower energy intake and higher physical activity. Anthropometric measurements, 2-hr plasma glucose, insulin, high-density lipoprotein cholesterol (HDL-C), and apolipoprotein B (ApoB) improved significantly for the total sample, and these benefits were similar among genotypes. Only variant allele carriers of FTO T/A decreased fasting plasma glucose after intervention (99.9±1.3 to 95.6±1.4 mg/dL, P=0.021). Mean blood pressure reduced after intervention in variant allele carriers of the PPARγ Pro12Ala (109.4±2.1 to 101.3±2.1 mmHg, P<0.001). Improvement in lipid variables was not significant after adjustment for medication. Only the reference genotype of PPARγ Pro12Ala increased apolipoprotein A1 (ApoA1) after intervention (134.3±2.4 to 140.6±2.3 mg/dL, P<0.001). Only variant allele carriers of FTO reduced C-reactive protein (CRP) concentration (0.366±0.031 to 0.286±0.029 mg/dL, P=0.023).

CONCLUSION

In Brazilian individuals, the FTO T/A polymorphism induces a favorable impact on inflammatory status and glucose metabolism. The reference genotype of PPARγ Pro12Ala seems to favor a better lipid profile, while the variant allele decreases blood pressure. Our data did not support benefits of the variant allele of ApoA1 -75G/A polymorphism. Further studies are needed to direct lifestyle intervention to subsets of individuals at cardiometabolic risk.

Mortality in middle-aged men with obstructive sleep apnea in Finland

INTRODUCTION

Obstructive sleep apnea (OSA) has been associated with an elevated rate of cardiovascular mortality. However, this issue has not been investigated in patients with elevated proneness to cardiovascular diseases. Our hypothesis was that OSA would have an especially adverse effect on the risk of cardiovascular mortality in Finnish individuals exhibiting elevated proneness for coronary heart diseases.

METHODS

Ambulatory polygraphic recordings from 405 men having suspected OSA were retrospectively analyzed. The patients were categorized regarding sleep disordered breathing into a normal group (apnea hypopnea index (AHI) < 5, n = 104), mild OSA group (5 ≤ AHI < 15, n = 100), and moderate to severe OSA group (AHI ≥ 15, n = 201). In addition, basic anthropometric and health data were collected. In patients who died during the follow-up period (at least 12 years and 10 months), the primary and secondary causes of death were recorded.

RESULTS

After adjustment for age, BMI, and smoking, the patients with moderate to severe OSA suffered significantly (p < 0.05) higher mortality (hazard ratio 3.13) than their counterparts with normal recordings. The overall mortality in the moderate to severe OSA group was 26.4 %, while in the normal group it was 9.7 %. Hazard ratio for cardiovascular mortality was 4.04 in the moderate to severe OSA and 1.87 in the mild OSA group.

CONCLUSIONS

OSA seems to have an especially adverse effect on the cardiovascular mortality of patients with an elevated genetic susceptibility to coronary heart diseases. When considering that all our patients had possibility of continuous positive airway pressure treatment and our reference group consisted of patients suffering from daytime somnolence, the hazard ratio of 4.04 for cardiovascular mortality in patients with moderate to severe disease is disturbingly high.

Genetic determinants of obesity and related vascular diseases

Obesity is one of the major risk factors of vascular diseases, and its prevalence is increasing worldwide. In the past decade, progress has been made in the understanding of genetic determinants of obesity and obesity-associated diseases. Genome-wide association studies identified a number of genetic variants associated with obesity. In addition to common variants, FTO and MC4R, new loci, such as TMEM18, KCTD15, GNPDA2, SH2B1, MTCH2, and NEGR1 have been detected. In the past years, abdominal obesity has been shown to be a more important vascular risk factor than the body mass index. In the context of vascular risk assessment, identification of genetic polymorphisms associated with accumulation of visceral fat is of special importance. Some polymorphisms associated with abdominal obesity, such as variants of gene encoding microsomal triglyceride transfer protein, have been already discovered. In this chapter, we provide a review of genetic determinants of obesity and discuss their role in obesity-related vascular diseases.

Reversible RNA adenosine methylation in biological regulation

N(6)-methyladenosine (m(6)A) is a ubiquitous modification in mRNA and other RNAs across most eukaryotes. For many years, however, the exact functions of m(6)A were not clearly understood. The discovery that the fat mass and obesity-associated protein (FTO) is an m(6)A demethylase indicates that this modification is reversible and dynamically regulated, suggesting that it has regulatory roles. In addition, it has been shown that m(6)A affects cell fate decisions in yeast and plant development. Recent affinity-based m(6)A profiling in mouse and human cells further showed that this modification is a widespread mark in coding and noncoding RNA (ncRNA) transcripts and is likely dynamically regulated throughout developmental processes. Therefore, reversible RNA methylation, analogous to reversible DNA and histone modifications, may affect gene expression and cell fate decisions by modulating multiple RNA-related cellular pathways, which potentially provides rapid responses to various cellular and environmental signals, including energy and nutrient availability in mammals.

Genetic prediction of common diseases. Still no help for the clinical diabetologist!

Genome-wide association studies (GWAS) have identified several loci associated with many common, multifactorial diseases which have been recently used to market genetic testing directly to the consumers. We here addressed the clinical utility of such GWAS-derived genetic information in predicting type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) in diabetic patients. In addition, the development of new statistical approaches, novel technologies of genome sequencing and ethical, legal and social aspects related to genetic testing have been also addressed. Available data clearly show that, similarly to what reported for most common diseases, genetic testing offered today by commercial companies cannot be used as predicting tools for T2DM and CAD. Further studies taking into account the complex interaction between genes as well as between genetic and non-genetic factors, including age, obesity and glycemic control which seem to modify genetic effects on the risk of T2DM and CAD, might mitigate such negative conclusions. Also, addressing the role of relatively rare variants by next generation sequencing may help identify novel and strong genetic markers with an important role in genetic prediction. Finally, statistical tools concentrated on reclassifying patients might be a useful application of genetic information for predicting many common diseases. By now, prediction of such diseases, including those of interest for the clinical diabetologist, have to be pursued by using traditional clinical markers which perform well and are not costly.

Association between FTO 1st intron tagging variant and telomere length in middle aged females. 3PMFs study

The FTO gene plays an important role in the determination of body weight and BMI and it has been suspected of being associated with all-cause mortality, cardiovascular disease, cancer and end stage renal disease, but the causal mechanism of these effects is still unknown. One of the possibilities is the potential association with telomere length. Telomeres are repetitive DNA-sequences located at the ends of eukaryotic chromosomes' length of which is reduced in all somatic cells during ageing. Out of the 908 females (3PMFs study), in 783 females both FTO 1st intron tagging polymorphism (G>T, rs17817449) and the relative telomere length were successfully analysed. The relative telomere length was calculated as the ratio of telomere repeats to single-copy gene copies. The frequencies of the FTO genotypes were similar to other populations (GG=18.3%, GT=49.1% and TT=32.6%). We have detected, that the relative telomere length was significantly shorter (P<0.02, P<0.01 after adjustment for age, BMI, waist and subcutaneous fat), in carriers of at least one FTO risky (G) allele (0.85±0.39) in comparison to the carriers of the protective TT genotype (0.93±0.48). We have demonstrated that the FTO variant could be associated with the relative telomere length. Whether this represents a causality of association between the FTO variant and the non-communicable diseases needs to be further analysed.

The A-allele of the common FTO gene variant rs9939609 complicates weight maintenance in severe obese patients

OBJECTIVE

The A-allele of the fat mass and obesity-associated (FTO) gene variant rs9939609 has been associated with increased body weight, whereas no effect on weight loss during weight reduction programs has been observed. We questioned whether the AA-genotype interferes with weight stabilization after weight loss.

DESIGN

We conducted a monocentric, longitudinal study involving obese individuals. The FTO gene variant rs9939609 was genotyped in participants attending a weight reduction program that was divided into two phases: a weight reduction period with formula diet (12 weeks) and a weight maintenance phase (40 weeks). Body weight, body mass index (BMI), blood pressure and concentrations of blood glucose, total cholesterol, low-density lipoprotein, high-density lipoprotein and triglycerides were determined in week 0 (T(0)), after 12 weeks (T(1)) and at the end in week 52 (T(2)).

SUBJECTS

A total of 193 obese subjects aged between 18 and 72 years (129 female, 64 male; initial body weight: 122.4±22.3 kg, initial BMI: 41.8±6.7 kg m(-2)) were included.

RESULTS

Genotyping revealed 32.1% TT-, 39.4% AT- and 28.5% AA-genotype carriers. At T (0), carriers of the AA-genotype had significantly higher body weight (P=0.04) and BMI (P=0.005) than carriers of the TT-genotype. Of the 193 participants, 68 discontinued and 125 completed the program. Dropout rate was not influenced by genotype (P=0.33). Completers with AA-genotype showed significantly lower additional weight loss during the weight maintenance phase than TT-genotype carriers (P=0.02). Furthermore, among participants facing weight regain during weight maintenance (n=52), more subjects were carrying the AA-genotype (P=0.006). No influence of genotype on weight reduction under formula diet was observed (P=0.32).

CONCLUSION

In this program, the AA-genotype of rs9939609 was associated with a higher initial body weight and did influence success of weight stabilization. Thus, emphasizing the maintenance phase during a weight reduction program might result in better success for AA-genotype carriers.

An obesity-related FTO variant and the risk of preeclampsia in a Finnish study population

Previous studies have demonstrated a common variant of the obesity and fat mass-related FTO gene, rs9939609, to be associated with obesity, type 2 diabetes, and elevated blood pressure. We investigated whether the FTO SNP rs9939609 is associated with the risk of preeclampsia (PE) in a Finnish study population. 485 women with prior PE and 449 women who had given birth after a normotensive pregnancy were genotyped (TaqMan) for the SNP rs9939609. The prevalences of genotypes AA, AT, and TT were 15%, 53%, and 32%, respectively, among the PE cases, and 16%, 47%, and 37%, respectively, among the controls (P = 0.199). We found no evidence of an association between the FTO SNP rs9939609 and PE. However, our cases were dominated by severe, early-onset PE. Thus, we are unable to exclude an association with the milder, later-onset form of the disease in which the role of maternal metabolic predisposition could be more significant.

The fat-mass and obesity-associated (FTO) gene, physical activity, and risk of incident cardiovascular events in white women

BACKGROUND

Variation in the Fat-Mass and Obesity-Associated (FTO) gene has been associated with obesity, diabetes, and hypertension. However, its association with cardiovascular disease (CVD) in healthy populations and any interaction with physical activity remain unclear.

METHODS

The FTO rs8050136 allele was determined in a prospective cohort study of 21,674 apparently healthy White US women in the Women's Genome Health Study.

RESULTS

During a mean follow-up of 12.7±2.0 years, 664 incident CVD events occurred. The risk allele (A) was associated with higher prevalence of hypertension, diabetes, and metabolic syndrome (all P<.05). In a multivariate model, there was significant association of the risk allele with CVD (hazard ratio [HR] per allele copy 1.14, 95% CI 1.01-1.28) that was no longer significant after additional adjustment for body mass index (BMI) (HR 1.10, 95% CI 0.97-1.23). There was statistical evidence of an interaction between FTO and physical activity (P=.048). We found a significant association of FTO with CVD only among less-active (≤8.8 metabolic equivalent-h/wk) women (HR 1.19, 95% CI 1.02-1.38) in multivariate analyses that included BMI. More-active women did not have this increased risk (HR 0.96, 95% CI 0.79-1.16]). In a model that adjusted for BMI, less-active/high-risk (A/A) women were at 54% increased risk of developing CVD (HR 1.54, 95% CI 1.13-2.11), compared to more-active/low-risk (C/C) women.

CONCLUSIONS

Carriers of the FTO risk allele have an increased risk of CVD mediated by BMI. There appears to be an interaction with physical activity, such that this risk increase is only in less-active women.