Genetic variants in FTO associated with metabolic syndrome: a meta- and gene-based analysis

A Systematic Review of the Gene-Lifestyle Interactions on Metabolic Disease-Related Outcomes in Arab Populations

The increased prevalence of metabolic diseases in the Arab countries is mainly associated with genetic susceptibility, lifestyle behaviours, such as physical inactivity, and an unhealthy diet. The objective of this review was to investigate and summarise the findings of the gene-lifestyle interaction studies on metabolic diseases such as obesity and type 2 diabetes in Arab populations. Relevant articles were retrieved from a literature search on PubMed, Web of Science, and Google Scholar starting at the earliest indexing date through to January 2024. Articles that reported an interaction between gene variants and diet or physical activity were included and excluded if no interaction was investigated or if they were conducted among a non-Arab population. In total, five articles were included in this review. To date, among three out of twenty-two Arab populations, fourteen interactions have been found between the FTO rs9939609, TCF7L2 rs7903146, MC4R rs17782313, and MTHFR rs1801133 polymorphisms and diet or physical activity on obesity and type 2 diabetes outcomes. The majority of the reported gene-diet/ gene-physical activity interactions (twelve) appeared only once in the review. Consequently, replication, comparisons, and generalisation of the findings are limited due to the sample size, study designs, dietary assessment tools, statistical analysis, and genetic heterogeneity of the studied sample.

The interaction between insulin resistance and Alzheimer's disease: a review article

Insulin serves multiple functions as a growth-promoting hormone in peripheral tissues. It manages glucose metabolism by promoting glucose uptake into cells and curbing the production of glucose in the liver. Beyond this, insulin fosters cell growth, drives differentiation, aids protein synthesis, and deters degradative processes like glycolysis, lipolysis, and proteolysis. Receptors for insulin and insulin-like growth factor-1 are widely expressed in the central nervous system. Their widespread presence in the brain underscores the varied and critical functions of insulin signaling there. Insulin aids in bolstering cognition, promoting neuron extension, adjusting the release and absorption of catecholamines, and controlling the expression and positioning of gamma-aminobutyric acid (GABA). Importantly, insulin can effortlessly traverse the blood-brain barrier. Furthermore, insulin resistance (IR)-induced alterations in insulin signaling might hasten brain aging, impacting its plasticity and potentially leading to neurodegeneration. Two primary pathways are responsible for insulin signal transmission: the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway, which oversees metabolic responses, and the mitogen-activated protein kinase (MAPK) pathway, which guides cell growth, survival, and gene transcription. This review aimed to explore the potential shared metabolic traits between Alzheimer's disease (AD) and IR disorders. It delves into the relationship between AD and IR disorders, their overlapping genetic markers, and shared metabolic indicators. Additionally, it addresses existing therapeutic interventions targeting these intersecting pathways.

Mechanisms and risk factors of metabolic syndrome in children and adolescents

Metabolic syndrome (MetS) is a complex disorder characterized by abdominal obesity, elevated blood pressure, hyperlipidemia, and elevated fasting blood glucose levels. The diagnostic criteria for MetS in adults are well-established, but there is currently no consensus on the definition in children and adolescents. The etiology of MetS is believed to involve a complex interplay between genetic predisposition and environmental factors. While genetic predisposition explains only a small part of MetS pathogenesis, modifiable environmental risk factors play a significant role. Factors such as maternal weight during pregnancy, children's lifestyle, sedentariness, high-fat diet, fructose and branched-chain amino acid consumption, vitamin D deficiency, and sleep disturbances contribute to the development of MetS. Early identification and treatment of MetS in children and adolescents is crucial to prevent the development of chronic diseases later in life. In this review we discuss the latest research on factors contributing to the pathogenesis of MetS in children, focusing on non-modifiable and modifiable risk factors, including genetics, dysbiosis and chronic low-grade inflammation.

Insulin resistance in Alzheimer's disease: The genetics and metabolomics links

Alzheimer's disease (AD) is a neurodegenerative disease with significant socioeconomic burden worldwide. Although genetics and environmental factors play a role, AD is highly associated with insulin resistance (IR) disorders such as metabolic syndrome (MS), obesity, and type two diabetes mellitus (T2DM). These findings highlight a shared pathogenesis. The use of metabolomics as a downstream systems' biology (omics) approach can help to identify these shared metabolic traits and assist in the early identification of at-risk groups and potentially guide therapy. Targeting the shared AD-IR metabolic trait with lifestyle interventions and pharmacological treatments may offer promising AD therapeutic approach. In this narrative review, we reviewed the literature on the AD-IR pathogenic link, the shared genetics and metabolomics biomarkers between AD and IR disorders, as well as the lifestyle interventions and pharmacological treatments which target this pathogenic link.

Precision medicine and metabolic syndrome

Metabolic syndrome (MetS) is one of the most important health issues around the world and a major risk factor for both type 2 diabetes mellitus (T2DM) and cardiovascular diseases. The etiology of MetS is determined by the interaction between genetic and environmental factors. Effective prevention and treatment of MetS notably decreases the risk of its complications such as diabetes, obesity, hypertension, and dyslipidemia. According to recent genome-wide association studies, multiple genes are involved in the incidence and development of MetS. The presence of particular genes which are responsible for obesity and lipid metabolism, affecting insulin sensitivity and blood pressure, as well as genes associated with inflammation, can increase the risk of MetS. These molecular markers, together with clinical data and findings from proteomic, metabolomic, pharmacokinetic, and other methods, would clarify the etiology and pathophysiology of MetS and facilitate the development of personalized approaches to the management of MetS. The application of personalized medicinebased on susceptibility identified genomes would help physicians recommend healthier lifestyles and prescribe medications to improve various aspects of health in patients with MetS. In recent years, personalized medicine by genetic testing has helped physicians determine genetic predisposition to MetS, prevent the disease by behavioral, lifestyle-related, or therapeutic interventions, and detect, diagnose, treat, and manage the disease. Clinically, personalized medicine is providing effective strategies for the prevention and treatment of MetS by reducing the time, cost, and failure rate of pharmaceutical clinical trials. It is also eliminating trial-and-error inefficiencies that inflate health care costs and undermine patient care.

Caveolin-1 genetic polymorphism interacts with PUFA to modulate metabolic syndrome risk

Several studies have reported a significant association between the metabolic syndrome (MetS) and mortality around the world. Caveolin-1 (CAV-1) has been widely studied in dyslipidaemia, and several studies have indicated that CAV-1 genetic variations may correlate with dietary intake of fatty acids. This study aimed to investigate the interaction of CAV-1 rs3807992 with types of dietary fatty acid in the MetS risk. This cross-sectional study was carried out on 404 overweight and obese females. Dietary intake was obtained from a 147-item FFQ. The CAV-1 genotype was measured using the PCR-restriction fragment length polymorphism method. Anthropometric values and serum levels (TC, LDL, HDL, TAG and FBS) were measured by standard methods. It was observed that the (AA + AG) group had significantly higher BMI, waist circumference and DBP (P = 0·02, P = 0·02, and P = 0·01, respectively) and lower serum LDL, HDL and TC (P < 0·05) than the GG group. It was found that A allele carriers were at higher odds of the MetS (P = 0·01), abdominal obesity (P = 0·06), increased TAG concentration (P = 0·01), elevated blood pressure (BP) (P = 0·01), increased glucose concentration (P = 0·45) and decreased HDL-cholesterol concentration (P = 0·03). Moreover, the interaction of CAV-1 and SFA intake was significant in terms of the MetS (P = 0·03), LDL (P = 0·03) and BP (P = 0·01). Additionally, the (AA + AG) group was significantly related to PUFA intake in terms of the MetS (P = 0·04), TAG (P = 0·02), glucose (P = 0·02) and homoeostasis model assessment insulin resistance (P = 0·01). Higher PUFA consumption might attenuate the CAV-1 rs3807992 associations with the MetS, and individuals with greater genetic predisposition appeared to have a higher risk of the MetS, associated with higher SFA consumption.

Metabolic syndrome and underlying genetic determinants-A systematic review

The metabolic syndrome is a cluster of heritable and related traits which has been associated with a range of pathophysiological factors including dyslipidaemia, abdominal obesity, increased fasting plasma glucose (FPG) and hypertension. The documented genetic basis of the metabolic syndrome include several chromosomal positions, numerous candidate gene-associated polymorphisms, different genetic variants, which are linked to the syndrome either as a trait or entities mainly linked to metabolic process. Additionally, the latest findings related to the contribution of epigenetic mechanisms, microRNAs, sporadic variants, non-coding RNAs, and assessing the role of genes in molecular systems has enhanced our understanding of the syndrome. Considerable work has been done to understand the underlying disease mechanisms by elucidating its genetic etiology. Nonetheless, a common shared genetic cause has not been established to clarify the coexistence of their components and further investigation is required. While mostly neglected and rarely known, hereditary predisposition needs to be studied, including with the current defective phenotypic condition descriptions. Metabolic syndrome is a multi-faceted characteristic with abundant properties and the condition can arise from interactions between environmental variables such as physical inactivity, caloric obesity and genetic susceptibility. Although there is support for genetic determinants from family and twin research, there is still no recognised genomic DNA marker for genetic association and linkages with quite a long way off potential for clinical application. In the present review efforts have been made to through light on the various genetic determinants with large effects that underlie with the association of these traits to this syndrome. The heterogeneity and multifactorial heritability of MetS, however, has been a challenge towards understanding the factors underlying the association of these traits.

The multifaceted functions of the Fat mass and Obesity-associated protein (FTO) in normal and cancer cells

The last decade has seen mRNA modification emerge as a new layer of gene expression regulation. The Fat mass and obesity-associated protein (FTO) was the first identified eraser of N6-methyladenosine (m6A) adducts, the most widespread modification in eukaryotic messenger RNA. This discovery, of a reversible and dynamic RNA modification, aided by recent technological advances in RNA mass spectrometry and sequencing has led to the birth of the field of epitranscriptomics. FTO crystallized much of the attention of epitranscriptomics researchers and resulted in the publication of numerous, yet contradictory, studies describing the regulatory role of FTO in gene expression and central biological processes. These incongruities may be explained by a wide spectrum of FTO substrates and RNA sequence preferences: FTO binds multiple RNA species (mRNA, snRNA and tRNA) and can demethylate internal m6A in mRNA and snRNA, N6,2'-O-dimethyladenosine (m6Am) adjacent to the mRNA cap, and N1-methyladenosine (m1A) in tRNA. Here, we review current knowledge related to FTO function in healthy and cancer cells. In particular, we emphasize the divergent role(s) attributed to FTO in different tissues and subcellular and molecular contexts.

Genetic Studies of Metabolic Syndrome in Arab Populations: A Systematic Review and Meta-Analysis

Background: The metabolic syndrome (MetS) is prevalent in Arabian populations. Several small-scale studies have been performed to investigate the genetic basis of MetS. This systematic review and meta-analysis aimed to examine whether candidate gene polymorphisms are associated with MetS susceptibility among ethnic groups of the Arabian world and to suggest possible directions for future research regarding genetic markers and MetS.

Methods: A search was conducted for peer-reviewed articles that examined the genetic association of MetS in Arabian populations in the following databases: Medline, Embase, Scopus, Direct Science, Web of Science, ProQuest, and Google Scholar until March 31, 2021. Articles were eligible if they were case-control studies, which investigated MetS as a dichotomous outcome (MetS vs no MetS). To assess the quality of the studies, the Q-Genie tool (Quality of Genetic Association Studies) was used. A non-central chi2 (random-effect) distribution was used to determine the heterogeneity (H) of Q and I (Galassi et al., The American journal of medicine, 2006, 119, 812–819) statistics.

Results: Our search strategy identified 36 studies that met our inclusion criteria. In most cases, studies were excluded due to a lack of statistical information such as odds ratios, confidence intervals, and p-values. According to the Q-Genie tool, 12 studies scored poorly (a score of≤35), 13 studies scored moderately ( >35 and≤45), and 12 studies had good quality ( >45 or higher). The most frequently studied genes were FTO and VDR (both included in four studies). Three SNPs indicated increased risk for MetS after calculating the pooled odds ratios: FTO-rs9939609 (odds ratio 1.49, 95% CI: 0.96–2.32); LEP-rs7799039 (odds ratio 1.85, 95% CI: 1.37–2.5); and SERPINA12-rs2236242 (odds ratio 1.65, 95% CI: 1.21–2.24). Meta-analysis studies showed no significant heterogeneity.

Conclusion: There were many sources of heterogeneity in the study settings. Most of the studies had low to moderate quality because of sample size and power issues, not considering all potential sources of bias, and not providing details about genotyping methods and results. As most studies were small-scale, aimed to replicate findings from other populations, we did not find any unique genetic association between MetS and Arabian populations.

Association between the FTO SNP rs9939609 and Metabolic Syndrome in Chilean Children

Background: The increasing prevalence of obesity in children has raised the incidence of Metabolic Syndrome (MetS) in this age group. Given the short- and long-term health impact of MetS, it is essential to prevent its onset by detecting its main triggers. Besides, genetic factors play an essential role in influencing which individuals within a population are most likely to develop obesity in response to a particular environment. In this regard, a common variation in the FTO gene is reproducibly associated with BMI and obesity from childhood and the genetic load has been linked to several cardiovascular risk factors, highlighting the FTO single nucleotide polymorphism (SNP) rs9939609. Therefore, this study aimed to establish the relationship between the FTO SNP rs9939609 and MetS. Methods: A cross-sectional study was carried out on 220 children from the Biobío region (Chile). MetS diagnosis was established through the modified Cook criteria, using prevalence ratios, COR curves, and linear regressions to determine its association with MetS and its components. Results: The prevalence of MetS was significantly increased among carriers of the risk allele (A): TT, 20.2%; TA, 25.4%; AA, 44.7% (p = 0.006). Also, the presence of A was associated with altered MetS-related variables. Conclusions: The FTO SNP rs9939609 was associated with a raised prevalence of MetS among A allele carriers, and was higher in the homozygous genotype (AA).

Ancestry specific associations of a genetic risk score, dietary patterns and metabolic syndrome: a longitudinal ARIC study

BACKGROUND

Associations have been observed among genetic variants, dietary patterns, and metabolic syndrome (MetS). A gap in knowledge is whether a genetic risk score (GRS) and dietary patterns interact to increase MetS risk among African Americans. We investigated whether MetS risk was influenced by interaction between a GRS and dietary patterns among Whites and African Americans. A secondary aim examined if molecular genetic clusterings differed by racial ancestry.

METHODS

We used longitudinal data over 4-visits (1987-1998) that included 10,681 participants aged 45-64y at baseline from the Atherosclerosis Risk in Communities study (8451 Whites and 2230 African Americans). We constructed a simple-count GRS as the linear weighted sum of high-risk alleles (0, 1, 2) from cardiovascular disease polymorphisms from the genome-wide association studies catalog associated with MetS risk. Three dietary patterns were determined by factor analysis of food frequency questionnaire data: Western, healthy, and high-fat dairy. MetS was defined according to the 2016 National Cholesterol Education Program Adult Treatment Panel III criteria but used 2017 American Heart Association/American College of Cardiology criteria for elevated blood pressure. Analyses included generalized linear model risk ratios (RR), 95% confidence intervals (CI), and Bonferroni correction for multiple testing.

RESULTS

The Western dietary pattern was associated with higher risk for MetS across increasing GRS tertiles among Whites (p < 0.017). The high-fat dairy pattern was protective against MetS, but its impact was most effective in the lowest GRS tertile in Whites (RR = 0.62; CI: 0.52-0.74) and African Americans (RR = 0.67; CI: 0.49-0.91). Among each racial group within GRS tertiles, the Western dietary pattern was associated with development and cycling of MetS status between visits, and the high-fat dairy pattern with being free from MetS (p < 0.017). The healthy dietary pattern was associated with higher risk of MetS among African Americans which may be explained by higher sucrose intake (p < 0.0001). Fewer genes, but more metabolic pathways for obesity, body fat distribution, and lipid and carbohydrate metabolism were identified in African Americans than Whites. Some polymorphisms were linked to the Western and high-fat dairy patterns.

CONCLUSION

The influence of dietary patterns on MetS risk appears to differ by genetic predisposition and racial ancestry.

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.

Clinical correlations and genetic associations of metabolic syndrome in the United Arab Emirates

BACKGROUND

Metabolic syndrome (MetS) contributes to increased risk of morbidity and mortality. The United Arab Emirates (UAE) has a high prevalence of MetS which may be linked to modifiable and genetic risk factors in the local population. The association between MetS as a phenotype and key genetic variants in the UAE has not been investigated. This study reports on the clinical, biochemical and genetic associations of MetS and its risk factors to improve individualized medicine outcomes.

METHODS

There were 471 subjects included in this cross-sectional study, 367 with MetS and 104 without MetS. Along with clinical and laboratory parameters, multiple risk genetic variants were tested for their association with MetS, which include 49 variants that have previously been shown to be linked with MetS development as a phenotype, 116 variants for association with waist-hip ratio (WHR), 398 variants with body-mass index (BMI), 213 variants with T2DM and insulin resistance, 307 variants with different lipid traits, 308 variants with blood pressure traits, and 64 variants with coronary and cerebrovascular accidents.

RESULTS

Patients with MetS had higher rates of type 2 diabetes mellitus (T2DM), hypertension and dyslipidemia (p < 0.0001). Waist circumference and T2DM were identified as the key risk factors for MetS development. Individuals with MetS were also found to have a higher rate of clinical complications than those without MetS (76% vs. 52%). Several gene variants including those of the FTO gene were found to be associated with a predisposition to developing MetS or some of its components (P_FTO ~0.005-0.009).

CONCLUSIONS

This study showed associations between MetS as well as clinical factors contributing to MetS and specific genetic and metabolic risk factors, providing an insight into the metabolic and genetic links to disease development. Knowledge with respect to population specific risk markers including at risk genotypes will help in early identification of individuals with increased susceptibility to MetS in the UAE and provide the opportunity for timely intervention to prevent or delay the onset of MetS.

Common genetic variation in obesity, lipid transfer genes and risk of Metabolic Syndrome: Results from IDEFICS/I.Family study and meta-analysis

As the prevalence of metabolic syndrome (MetS) in children and young adults is increasing, a better understanding of genetics that underlie MetS will provide critical insights into the origin of the disease. We examined associations of common genetic variants and repeated MetS score from early childhood to adolescence in a pan-European, prospective IDEFICS/I.Family cohort study with baseline survey and follow-up examinations after two and six years. We tested associations in 3067 children using a linear mixed model and confirmed the results with meta-analysis of identified SNPs. With a stringent Bonferroni adjustment for multiple comparisons we obtained significant associations(p < 1.4 × 10⁻⁴) for 5 SNPs, which were in high LD (r² > 0.85) in the 16q12.2 non-coding intronic chromosomal region of FTO gene with strongest association observed for rs8050136 (effect size(β) = 0.31, p_Wald = 1.52 × 10⁻⁵). We also observed a strong association of rs708272 in CETP with increased HDL (p = 5.63 × 10⁻⁴⁰) and decreased TRG (p = 9.60 × 10⁻⁵) levels. These findings along with meta-analysis advance etiologic understanding of childhood MetS, highlighting that genetic predisposition to MetS is largely driven by genes of obesity and lipid metabolism. Inclusion of the associated genetic variants in polygenic scores for MetS may prove to be fundamental for identifying children and subsequently adults of the high-risk group to allow earlier targeted interventions.

Ancestry specific associations of FTO gene variant and metabolic syndrome: A longitudinal ARIC study

Cross-sectional studies indicate that the fat mass and obesity-associated (FTO) rs9939609 gene variant is associated with metabolic syndrome (MetS) primarily in European ancestry. However, the association is not fully elucidated in African Americans.We hypothesized that rs9939609 (AT = moderate-risk carriers or AA = high-risk carriers compared to TT = low-risk carriers) is associated with MetS and its component risk factors over time; and that its association is ancestry-specific. A secondary hypothesis was that higher levels of physical activity can decrease the deleterious effect of rs9939609 at higher body mass index (BMI).Atherosclerosis Risk in Communities study repeated measures data from 4 visits (1987-1998) were obtained from the database of Genotypes and Phenotypes for 10,358 participants (8170 Whites and 2188 African Americans) aged 45 to 64 years at baseline. Guidelines for elevated blood pressure by the American College of Cardiology and American Heart Association Task Force were updated within the MetS criteria. Risk ratios (RR) and 95% confidence intervals from generalized estimating equations assessed population-average risks.MetS was present among 3479 (42.6%) Whites and 1098 (50.2%) African Americans at baseline, and 50.3% Whites and 57% African Americans over 11-years of follow-up. Among MetS component risk factors, high waist circumference was most prevalent among White AT (RR = 1.07; 1.06-1.09) and AA (RR = 1.12; 1.10-1.14) higher-risk carriers. High triglycerides were elevated among African American AA high-risk carriers (RR = 1.11; 1.02-1.21) compared to TT low-risk carriers. Over time, White AT-and AA higher-risk carriers had 1.07 and 1.08-fold increase (P < .0001) in MetS risk. Physical activity had independent protective effects on MetS among both races (P < .05). White AA high-risk carriers with normal BMI and low vs high physical activity had higher MetS risk (RR = 1.69; 1.25-2.30 and RR = 0.68;0.53-0.87, respectively). In rs9939609 × BMI× physical activity interaction, White A-allele high-risk carriers had lower MetS risk (RR = 0.68; 0.53-0.87). Among Whites, physical activity can lessen the effect of rs9939609 and high BMI on risk for MetS.

Association of FTO Gene Variant (rs8050136) with Type 2 Diabetes and Markers of Obesity, Glycaemic Control and Inflammation

Background

FTO, a gene recently discovered in genomewide associated studies for type 2 diabetes mellitus (T2D), play an important role in the management of energy homeostasis, nucleic acid demethylation and regulation of body fat mass by lipolysis. The aim of this study was to analyze the association of FTO rs8050136 A>C genetic variant with clinical and biochemical parameters of T2D in the population of West Balkan region (Bosnians and Herzegovinians and Kosovars).

Methods

The study included 638 patients with T2D and prediabetes and 360 healthy controls of both genders, aged from 40 to 65 years. Patients were recruited at the Clinical Centre University of Sarajevo, University Hospital of Clinical Centre in Banja Luka, General Hospital in Tešanj and Health Centre in Prizren. Genotyping of analyzed FTO polymorphism rs8050136 A>C was performed by qPCR allelic discrimination.

Results

Genotype frequencies of the analyzed polymorphism were comparable between patients with T2D, prediabetic patients, and healthy population. Logistic regression analyses didn’t show significant association of FTO rs8050136 A allele with increased risk of T2D. However, risk A allele was significantly associated with higher levels of HbA1c, insulin, HOMA-IR index, diastolic blood pressure, and inflammatory markers (fibrinogen and leukocytes) as well as showed tendency of association with increased values of obesity markers (BMI, waist and hip circumference).

Conclusions

Results of our study showed a significant association of FTO genetic variant rs8050136 A>C with the major markers of insulin resistance, obesity and inflammation, opening new avenues for solving many unclear questions in the pathogenesis of T2D.

Metabolic fitness in relation to genetic variation and leukocyte DNA methylation

Metabolic syndrome (MetS) is a highly prevalent condition causing increased risk of several life-threatening diseases. MetS has a pronounced hereditary basis but is also influenced by environmental factors, partly through epigenetic mechanisms. In this study, the five phenotypes underlying MetS were incorporated into a continuous score for metabolic fitness (MF), and associations with both genotypic variation and leukocyte DNA methylation were investigated. Baseline MF phenotypes (waist circumference, blood pressure, blood glucose, serum triglycerides, and high-density lipoproteins) of 710 healthy Flemish adults were measured. After a 10 yr period, follow-up measures were derived from 618 of these subjects. Genotyping was performed for 65 preselected MF-related genetic variants. Next, full genetic predisposition scores (GPSs) were calculated, combining genotype scores of multiple genetic variants. Additionally, stepwise GPSs were constructed, including only the most predictive genetic variants for the different MF phenotypes. For a subset of 68 middle-aged men, global and gene-specific DNA methylation was investigated, and a biological pathway analysis was performed. The full GPSs were predictive for some baseline MF phenotypes, but not for changes over time. Only a limited number of genetic variants were significantly predictive individually. On the contrary, global and gene-specific DNA methylation was associated with changes in the MF phenotypes rather than with the baseline measures, indicating that effects of DNA methylation on MF are somewhat delayed. Furthermore, several biological pathways were associated with the MF phenotypes through gene promoter methylation. For CETP, G6PC2, MC4R, and TFAP2B both a genetic and epigenetic relationship was found with MF.

Searching for Factors Raising the Incidence of Metabolic Syndrome Among 45-60-Year-Old Women

Metabolic syndrome is an increasing health problem, whose pathogenesis may be associated with genetic factors. The main purpose of our study was to assess relationships between MetS and the presence of the FTO rs9939609, the MC4R rs17782313, and the PPAR-γ rs1801282 polymorphisms in 45-60-year-old women. The study included patients from the general population of the Westpomeranian Province (Poland). The mean age was 54.3 ± 4.2 years. The research procedure involved taking structured history, physical examination, anthropometric measurements, and collecting blood for biochemical and genetic analysis. The patients who met the diagnostic criteria for MetS constituted 38.35% of all participants (sample size: 425 patients). The comparison of blood biochemical parameters revealed numerous differences between the women with MetS and those from the control group. Genetic analysis demonstrated that the T allele of the FTO gene was a factor substantially decreasing the incidence of MetS in the study sample (ORT vs. A = 0.734; 95% CI: 0.555 - 0.970; p < 0.05). Other polymorphisms were not directly related to MetS incidence.

CONCLUSIONS

1. MetS-related abnormalities are widespread in the population of 45-60-year-old Polish women. Those most common are the elevated serum total cholesterol and LDL levels, increased insulin resistance and BMI scores, as well as visceral obesity. 2. No direct relationships were demonstrated between MetS and the gene polymorphisms analyzed in our study except for the FTO rs9939609, whose A allele and A/A genotype seemed to predispose to metabolic disorders.

Molecular Biomarkers for Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a growing public health problem worldwide. The condition is associated with perinatal complications and an increased risk for future metabolic disease in both mothers and their offspring. In recent years, molecular biomarkers received considerable interest as screening tools for GDM. The purpose of this review is to provide an overview of the current status of single-nucleotide polymorphisms (SNPs), DNA methylation, and microRNAs as biomarkers for GDM. PubMed, Scopus, and Web of Science were searched for articles published between January 1990 and August 2018. The search terms included “gestational diabetes mellitus”, “blood”, “single-nucleotide polymorphism (SNP)”, “DNA methylation”, and “microRNAs”, including corresponding synonyms and associated terms for each word. This review updates current knowledge of the candidacy of these molecular biomarkers for GDM with recommendations for future research avenues.

The investigations of genetic determinants of the metabolic syndrome

Metabolic syndrome is the aggregation of cardiovascular risk factors that increases the risk of type 2 diabetes and cardiovascular diseases. Family and twin studies, heritability spectrum for its components and different prevalence among ethnicities, have provided genetic susceptibility to the metabolic syndrome. The investigations of genetic base for the disorder have recognized numerous chromosomes, various DNA polymorphisms in candidate genes and many gene variants, that are associated with metabolic syndrome as an entity or its traits, which mostly are related to lipid metabolism. In addition, recent finding of the role of rare variants, epigenetic mechanisms, non-coding RNAs and evaluating the function of genes in molecular networks have improved our knowledge. However, a common genetic basis explaining the co-occurrence of its components has not been identified and more researches are essential.

Lifestyle genomics and the metabolic syndrome: A review of genetic variants that influence response to diet and exercise interventions

Metabolic syndrome (MetS) comprises a cluster of risk factors that includes central obesity, dyslipidemia, impaired glucose homeostasis and hypertension. Individuals with MetS have elevated risk of type 2 diabetes and cardiovascular disease; thus placing significant burdens on social and healthcare systems. Lifestyle interventions (comprised of diet, exercise or a combination of both) are routinely recommended as the first line of treatment for MetS. Only a proportion of people respond, and it has been assumed that psychological and social aspects primarily account for these differences. However, the etiology of MetS is multifactorial and stems, in part, on a person's genetic make-up. Numerous single nucleotide polymorphisms (SNPs) are associated with the various components of MetS, and several of these SNPs have been shown to modify a person's response to lifestyle interventions. Consequently, genetic variants can influence the extent to which a person responds to changes in diet and/or exercise. The goal of this review is to highlight SNPs reported to influence the magnitude of change in body weight, dyslipidemia, glucose homeostasis and blood pressure during lifestyle interventions aimed at improving MetS components. Knowledge regarding these genetic variants and their ability to modulate a person's response will provide additional context for improving the effectiveness of personalized lifestyle interventions that aim to reduce the risks associated with MetS.

Prevalence of metabolic syndrome and its risk factors among rural adults in Nantong, China

The prevalence of metabolic syndrome (MS) varies worldwide due to genetic and environmental factors. A population-based cross-sectional study, with 37,582 participants recruited in Nantong, China in 2007-2008 (stage I) and 2013 (stage II). Socio-demographic, lifestyle factors, disease history and fasting blood sample were collected. The prevalence of MS was much higher in 2013 (42.6%) than that in 2007-2008 (21.6%), which was significantly higher in older people in both stages. Participants with two or more familial history of diseases were associated with a higher MS prevalence compared to those who didn’t have familial history of diseases. Total physical activity (PA) was associated with 24 and 19% decreased risk of MS in men and women. Occupational PA in moderate and vigorous intensity was associated with a 25%-45% decreased risk of MS. Female smokers who smoked more than 10 cigarettes per day or over 25 years were associated with 96 and 74% increased MS risk, respectively. The highest quartile of rice wine consumption was associated with a lower risk of MS with OR of 0.63 in women, compared with female non-drinkers. These findings indicated that PA and rice wine are two protective factors in MS prevention in rural areas of East China.

Metabolic Syndrome in Children and Adolescents

BACKGROUND

Juvenile obesity is associated with multiple cardiometabolic comorbidities, which may culminate in the metabolic syndrome (MetS).

METHODS

Based on a narrative review, the current knowledge of prevalence and the underlying metabolic principles regarding juvenile obesity and MetS are summarized to compile up-to-date information. In addition, the role of lifestyle as well as positive and negative influencing factors are focused on.

RESULTS

The prevalence of MetS occurs between 1 and up to 23% in the total pediatric population and in up to 60% amongst the obese and overweight. It can be considered as the consequence of multiple processes in terms of lifestyle, perinatal programming, and (epi-)genetic pathways; however, the complex underlying mechanisms and their interplay are not completely understood.

CONCLUSION

Besides preventive approaches, the growing number of obese children and youth as well as its consequences call for effective and lasting therapeutic measures.

The FTO gene is associated with a paradoxically favorable cardiometabolic risk profile in frail, obese older adults

OBJECTIVE

Fat mass and obesity-associated (FTO) gene polymorphisms have been reported to be associated with differences in BMI, obesity, and type 2 diabetes. However, previous studies have been predominantly conducted in younger individuals across a spectrum of body weights, whereas little information is available on the older population. We examined the association of FTO gene polymorphisms with cardiometabolic risks among adults who were both obese (BMI≥30 kg/m) and older (age≥65 years).

METHODS

A total of 165 frail, obese older adults were genotyped for FTO (rs9939609 and rs8050136) single nucleotide polymorphisms and studied for associations with body weight and body composition, components and prevalence of the metabolic syndrome, insulin response to an oral glucose tolerance test, and levels of adipocytokines (e.g. leptin) and vitamin D.

RESULTS

Carriers of the A allele (CA/AA) of the FTO single nucleotide polymorphism rs8050136 had lower body weight, BMI, body fat, and trunk fat than those without the A allele (CC genotype; all P's<0.05). Moreover, genotype CA/AA was associated with lower levels of triglycerides and higher levels of high-density lipoprotein-cholesterol and carriers of this genotype showed a trend toward a lower waist circumference, resulting in a lower prevalence of metabolic syndrome than in CC genotype carriers. The insulin area under the curve during the oral glucose tolerance test was lower for genotype CA/AA. Despite the lower insulin levels, the glucose area under the curve was unchanged, resulting in a higher insulin sensitivity index. Leptin levels were also lower and adiponectin and 25-hydroxyvitamin levels tended to be higher for genotype CA/AA than for genotype CC. No differences were observed for rs9939609.

CONCLUSION

Unlike the results from studies in younger individuals, the risk A allele may confer a favorable cardiometabolic risk profile in obese older adults, suggesting selective survival of obese adults into old age. If confirmed in a larger sample of surviving obese older adults, these findings may have implications in the clinical approach to obesity in this population.

Physical activity, but not dietary intake, attenuates the effect of the FTO rs9939609 polymorphism on obesity and metabolic syndrome in Lithuanian adult population

OBJECTIVES

This study aimed to examine the associations between the fat mass and obesity associated (FTO) gene rs9939609 variant with obesity and metabolic syndrome and interactions between FTO alleles, dietary intake and physical activity in Lithuanian adult population.

STUDY DESIGN

Cross-sectional study.

METHODS

A health survey was carried out in randomly selected municipalities of Lithuania. The random sample was obtained from the lists of 25-64 year-old inhabitants. The data from 1020 individuals were analyzed. The single-nucleotide polymorphism, rs9939609, in the FTO gene was assessed using a real-time polymerase chain reaction. 24-hour recall was used for evaluation of dietary habits. Information on physical activity at work, traveling to and from work and at leisure time was gathered by a standard questionnaire.

RESULTS

The carriers of the AA genotype had the highest mean values of body mass index (BMI) and waist circumference (WC). They had 1.72 time higher odds of obesity (P = 0.009) and 1.67 time higher odds of increased WC (P = 0.013) than those with the TT genotype. Carriers of the T allele had lower prevalence of metabolic syndrome compared to carriers of the AA genotype (33.8% and 42.5% respectively; P = 0.018). No interaction between the rs9939609 variant and energy or dietary intakes on weight status was found. Significant effect of the interactions 'genotype×age' and 'genotype×physical activity' on BMI was demonstrated. The FTO rs9939609 polymorphism was associated with anthropometric parameters and metabolic syndrome in the younger age group (25-44 years) and in individuals having low level of physical activity.

CONCLUSIONS

Age and physical activity modulated the effect of the FTO polymorphism on weight status and metabolic syndrome in Lithuanian adult population.

Association of genetic variants in the FTO gene with metabolic syndrome: A case-control study in the Tunisian population

AIMS

Variants in the fat mass and obesity-associated gene (FTO) are associated with obesity and type 2 diabetes. However, the association of FTO variants in the MENA (Middle East and North Africa) region with MetS is largely unknown. In this study, we aimed to investigate the association of FTO gene with MetS and its components in Tunisian population.

METHODS

Two variants in the FTO gene were genotyped: rs1421085 T>C and rs8057044 A>G in cases and controls from Tunisian population. Anthropometric and biochemical parameters were assessed. Metabolic syndrome was defined according to the International Diabetes Federation (IDF).

RESULTS

The FTO rs1421085 variant conferred an increased risk to MetS (OR=1.61, 95% CI=1.14-2.26, P=0.024) that was abolished when adjusted for fasting plasma glucose (FPG), suggesting that the association may be due to variation in FPG levels. Indeed, this variant was associated to FPG (OR = 1.7, 95% CI=1.23-2.44, P=0.002) independently from BMI or age. The second polymorphism rs8057044 was associated with high blood pressure levels (OR=1.45, 95% CI=1.06-1.99, P=0.019).

CONCLUSIONS

This is the first study highlighting the association between FTO gene variants and MetS in Tunisian population. These findings provide evidence that FTO gene may play a critical role in leading to MetS in Tunisian population.

Genetics of metabolic syndrome

Metabolic syndrome (MetS) is a cluster of metabolic traits associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. Central obesity and insulin resistance are thought to play key roles in the pathogenesis of the MetS. The MetS has a significant genetic component, and therefore linkage analysis, candidate gene approach, and genome-wide association (GWA) studies have been applied in the search of gene variants for the MetS. A few variants have been identified, located mostly in or near genes regulating lipid metabolism. GWA studies for the individual components of the MetS have reported several loci having pleiotropic effects on multiple MetS-related traits. Genetic studies have provided so far only limited evidence for a common genetic background of the MetS. Epigenetic factors (DNA methylation and histone modification) are likely to play important roles in the pathogenesis of the MetS, and they might mediate the effects of environmental exposures on the risk of the MetS. Further research is needed to clarify the role of genetic variation and epigenetic mechanisms in the development of the MetS.

FTO rs9939609 polymorphism is associated with metabolic disturbances and response to HCV therapy in HIV/HCV-coinfected patients

BACKGROUND

The Fat Mass and Obesity-Associated Protein (FTO) gene rs9939609 single nucleotide polymorphism (SNP) has been associated with obesity, metabolic syndrome, insulin resistance (IR), and type 2 diabetes mellitus in the general population. The aim of our study was to examine for the first time the association of the rs9939609 polymorphism with metabolic disturbances, liver disease and virologic response to hepatitis C virus (HCV) therapy with pegylated-interferon-alpha plus ribavirin (pegIFNα/RBV) in human immunodeficiency virus (HIV)/HCV coinfected patients.

METHODS

We carried out a cross-sectional study in 261 patients, of whom 178 were subsequently treated with pegIFNα/RBV therapy. FTO rs9939609 and IFNL3 rs12980275 polymorphisms were genotyped by GoldenGate®. The main outcomes were: 1) metabolic disturbances: insulin resistance (homeostatic model assessment (HOMA-IR)) and overweight (body mass index (BMI)); 2) liver disease (Metavir score): significant fibrosis (F ≥2) and steatosis (>10% fatty hepatocytes); and 3) virologic response to HCV treatment: sustained virologic response (SVR).

RESULTS

The rs9939609 AA genotype was associated with higher values of BMI (adjusted arithmetic mean ratio (aAMR) = 1.08; 95% confidence interval (95%CI) = 1.03 to 1.14; P = 0.002) and HOMA-IR (aAMR = 1.32; 95%CI = 1.03 to 1.69; P = 0.027). Patients with an rs9939609 AA genotype had higher likelihoods of achieving values of BMI ≥27.5 kg/m2 (adjusted odds ratio (aOR) = 3.46; 95%CI =1.17 to 10.21; P = 0.024), HOMA-IR ≥2.5 (aOR = 2.09; 95%CI = 1.02 to 4.32; P = 0.045), significant fibrosis (aOR = 2.34; 95%CI =1.02 to 5.36; P = 0.045) and steatosis (aOR = 3.65; 95%CI = 1.29 to 10.36; P = 0.015). The rs9939609 AT/AA genotype decreased the likelihood of achieving SVR (aOR = 0.58; 95%CI = 0.34 to 0.99; P = 0.044). A decision tree was performed with the genotypes of HCV, IFNL3 and FTO. The incorporation of rs9939609 significantly improves the prediction of SVR (P <0.05). The overall accuracy was 68.2%.

CONCLUSIONS

Patients carrying the unfavourable AT/AA genotype of rs9939609 polymorphism had higher odds of metabolic disturbances and a lower likelihood of achieving successful virologic response to HCV therapy.

Association of genetic variants in and promoter hypermethylation of CDH1 with gastric cancer: a meta-analysis

Gastric cancer (GC) is a common cause of cancer-related death. The etiology and pathogenesis of GC remain unclear, with genetic and epigenetic factors playing an important role. Previous studies investigated the association of GC with many genetic variants in and promoter hypermethylation of E-cadherin gene (CDH1), with conflicting results reported.To clarify this inconsistency, we conducted updated meta-analyses to assess the association of genetic variants in and the promoter hypermethylation of CDH1 with GC, including C-160A (rs16260) and other less-studied genetic variants,Data sources were PubMed, Cochrane Library, Google Scholar, Web of Knowledge, and HuGE, a navigator for human genome epidemiology.Study eligibility criteria and participant details are as follows: studies were conducted on human subjects; outcomes of interest include GC; report of genotype data of individual genetic variants in (or methylation status of) CDH1 in participants with and without GC (or providing odds ratios [OR] and their variances).Study appraisal and synthesis methods included the use of OR as a measure of the association, calculated from random effects models in meta-analyses. We used I for the assessment of between-study heterogeneity, and publication bias was assessed using funnel plot and Egger test.A total of 33 studies from 30 published articles met the eligibility criteria and were included in our analyses. We found no association between C-160A and GC (OR = 0.88; 95% confidence interval [CI], 0.71-1.08; P = 0.215), assuming an additive model (reference allele C). C-160A was associated with cardia (OR = 0.21; 95% CI, 0.11-0.41; P = 2.60 × 10), intestinal (OR = 0.66; 95% CI, 0.49-0.90; P = 0.008), and diffuse GC (OR = 0.57; 95% CI, 0.40-0.82; P = 0.002). The association of C-160A with noncardia GC is of bottom line significance (OR = 0.65; 95% CI, 0.42-1.01; P = 0.054). Multiple other less-studied genetic variants in CDH1 also exhibited association with GC. Gene-based analysis indicated a significant cumulative association of genetic variants in CDH1 with GC (all Ps <10). Sensitivity analysis excluding studies not meeting Hardy-Weinberg equilibrium (HWE) yielded similar results. Analysis by ethnic groups revealed significant association of C-160A with cardia GC in both Asian and whites, significant association with noncardia GC only in Asians, and no significant association with intestinal GC in both ethnic groups. There was significant association of C160-A with diffuse GC in Asians (P = 0.011) but not in whites (P = 0.081). However, after excluding studies that violate HWE, this observed association is no longer significant (P = 0.126). We observed strong association of promoter hypermethylation of CDH1 with GC (OR = 12.23; 95% CI, 8.80-17.00; P = 1.42 × 10), suggesting that epigenetic regulation of CDH1 could play a critical role in the etiology of GC.Limitations of this study are as follows: we could not adjust for confounding factors; some meta-analyses were based on a small number of studies; sensitivity analysis was limited due to unavailability of data; we could not test publication bias for some meta-analyses due to small number of included studies.We found no significant association of the widely studied genetic variant C-160A, but identified some other genetic variants showing significant association with GC. Future studies with large sample sizes that control for confounding risk factors and/or intensively interrogate CpG sites in CDH1 are needed to validate the results found in this study and to explore additional epigenetic loci that affect GC risk.

FTO is a relevant factor for the development of the metabolic syndrome in mice

The metabolic syndrome is a worldwide problem mainly caused by obesity. FTO was found to be a obesity-risk gene in humans and FTO deficiency in mice led to reduction in adipose tissue. Thus, FTO is an important factor for the development of obesity. Leptin-deficient mice are a well characterized model for analysing the metabolic syndrome. To determine the relevance of FTO for the development of the metabolic syndrome we analysed different parameters in combined homozygous deficient mice (Lep(ob/ob);Fto(-/-)). Lep(ob/ob);Fto(-/-) mice showed an improvement in analysed hallmarks of the metabolic syndrome in comparison to leptin-deficient mice wild type or heterozygous for Fto. Lep(ob/ob);Fto(-/-) mice did not develop hyperglycaemia and showed an improved glucose tolerance. Furthermore, extension of beta-cell mass was prevented in Lep(ob/ob);Fto(-/-)mice and accumulation of ectopic fat in the liver was reduced. In conclusion this study demonstrates that FTO deficiency has a protective effect not only on the development of obesity but also on the metabolic syndrome. Thus, FTO plays an important role in the development of metabolic disorders and is an interesting target for therapeutic agents.

The effects of genetic variation in FTO rs9939609 on obesity and dietary preferences in Chinese Han children and adolescents

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

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 role of common and rare MC4R variants and FTO polymorphisms in extreme form of obesity

Melanocortin 4 receptor (MC4R) is an important regulator of food intake and number of studies report genetic variations influencing the risk of obesity. Here we explored the role of common genetic variation from MC4R locus comparing with SNPs from gene FTO locus, as well as the frequency and functionality of rare MC4R mutations in cohort of 380 severely obese individuals (BMI > 39 kg/m(2)) and 380 lean subjects from the Genome Database of Latvian Population (LGDB). We found correlation for two SNPs--rs11642015 and rs62048402 in the fat mass and obesity-associated protein (FTO) with obesity but no association was detected for rs17782313 located in the MC4R locus in these severely obese individuals. We sequenced the whole gene MC4R coding region in all study subjects and found five previously known heterozygous non-synonymous substitutions V103I, I121T, S127L, V166I and I251L. Expression in mammalian cells showed that the S127L, V166I and double V103I/S127L mutant receptors had significantly decreased quantity at the cell surface compared to the wild type MC4R. We carried out detailed functional analysis of V166I that demonstrated that, despite low abundance in plasma membrane, the V166I variant has lower EC50 value upon αMSH activation than the wild type receptor, while the level of AGRP inhibition was decreased, implying that V166I cause hyperactive satiety signalling. Overall, this study suggest that S127L may be the most frequent functional MC4R mutation leading to the severe obesity in general population and provides new insight into the functionality of population based variants of the MC4R.

An obesity genetic risk score is associated with metabolic syndrome in Chinese children

Recent genome-wide association studies have identified several single nucleotide polymorphisms (SNPs) associated with body mass index (BMI)/obesity. In this study, we aim to examine the associations of obesity related loci with risk of metabolic syndrome (MetS) in a children population from China. A total of 431 children with MetS and 3046 controls were identified based on the modified ATPIII definition. 11 SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265, FAIM2 rs7138803, NPC1 rs1805081, SEC16B rs10913469, SH2B1 rs4788102, PCSK1rs6235, KCTD15 rs29941, BAT2 rs2844479) were genotyped by TaqMan 7900. Of 11 SNPs, GNPDA2 rs10938397, BDNF rs6265, and FAIM2 rs7138803 were nominally associated with risk of MetS (GNPDA2 rs10938397: odds ratio (OR)=1.21, 95% confidence interval (CI)=1.04-1.40, P=0.016; BDNF rs6265: OR=1.19, 95% CI=1.03-1.39, P=0.021; FAIM2 rs7138803: OR=1.20, 95% CI=1.02-1.40, P=0.025); genetic risk score (GRS) was significantly associated with risk of MetS (OR=1.09, 95% CI=1.04-1.15, P=5.26×10(-4)). After further adjustment for BMI, none of SNPs were associated with risk of MetS (all P>0.05); the association between GRS and risk of MetS remained nominally (OR=1.02, 95%CI=0.96-1.08, P=0.557). However, after correction for multiple testing, only GRS was statistically associated with risk of MetS in the model without adjustment for BMI. The present study demonstrated that there were nominal associations of GNPDA2 rs10938397, BDNF rs6265, and FAIM2 rs7138803 with risk of MetS. The SNPs in combination have a significant effect on risk of MetS among Chinese children. These associations above were mediated by adiposity.

From obesity genetics to the future of personalized obesity therapy

Obesity is a disorder characterized by an excess accumulation of body fat resulting from a mismatch between energy intake and expenditure. Incidence of obesity has increased dramatically in the past few years, almost certainly fuelled by a shift in dietary habits owing to the widespread availability of low-cost, hypercaloric foods. However, clear differences exist in obesity susceptibility among individuals exposed to the same obesogenic environment, implicating genetic risk factors. Numerous genes have been shown to be involved in the development of monofactorial forms of obesity. In genome-wide association studies, a large number of common variants have been associated with adiposity levels, each accounting for only a small proportion of the predicted heritability. Although the small effect sizes of obesity variants identified in genome-wide association studies currently preclude their utility in clinical settings, screening for a number of monogenic obesity variants is now possible. Such regular screening will provide more informed prognoses and help in the identification of at-risk individuals who could benefit from early intervention, in evaluation of the outcomes of current obesity treatments, and in personalization of the clinical management of obesity. This Review summarizes current advances in obesity genetics and discusses the future of research in this field and the potential relevance to personalized obesity therapy.

No association of genetic variants in BDNF with major depression: a meta- and gene-based analysis

Major depressive disorder (MDD) is a complex psychiatric condition with strong genetic predisposition. The association of MDD with genetic polymorphisms, such as Val66Met (rs6265), in the brain derived neurotrophic factor (BDNF), have been reported in many studies and the results were conflicting. In this study, we performed a systematic literature search and conducted random-effects meta-analysis to evaluate genetic variants in BDNF with MDD. A gene-based analysis was also conducted to investigate the cumulative effects of genetic polymorphisms in BDNF. A total of 28 studies from 26 published articles were included in our analysis. Meta-analysis yielded an estimated odds ratio (OR) of 0.96 (95% CI: 0.89-1.05; P = 0.402) for Val66Met (rs6265), 0.83 (95% CI: 0.67-1.04; P = 0.103) for 11757C/G, 1.16 (95% CI: 0.74-1.82; P = 0.527) for 270T/C, 1.03 (95% CI: 0.18-5.75; P = 0.974) for 712A/G and 0.98 (95% CI: 0.85-1.14; P = 0.831) for rs988748. The gene-based analysis indicated that BDNF is not associated with MDD (P > 0.21). Our updated meta- and novel gene-based analyses provide no evidence of the association of BDNF with major depression.

Prevalence and determinants of metabolic syndrome among women in Chinese rural areas

Background and Aims

Metabolic syndrome (MS) is prevalent in recent years but few data is reported in the rural areas in China. The aim of this study was to examine MS prevalence and its risk factors among women in rural China.

Methods and Results

The Nantong Metabolic Syndrome Study (NMSS), a population based cross-sectional study, was conducted during 2007–2008 in Nantong, China. In person interviews, blood glucose and lipid measurements were completed for 13,505 female participants aged 18–74 years. The International Diabetes Federation (IDF), the US Third Report of the National Cholesterol Education Program, the Adult Treatment Panel (ATPIII) and modified ATPIII for Asian population has determined three criteria of MS. These criteria for MS were used and compared in this study. The prevalence of MS was 22.0%, 16.9% and 23.3% according to IDF, ATPIII and ATPIII-modified criteria, respectively. Levels of agreement of these criteria for MS were above 0.75. We found that vigorous-intensity of occupational physical activity was associated with a low prevalence of MS with OR of 0.76 (95% confidence interval (CI): 0.63–0.91). Rice wine drinkers (alcohol >12.8 g/day) had about 34% low risks of developing MS with OR of 0.66 (95% CI: 0.48–0.91), compared with non-drinkers. Odds ratio of MS was 1.81 (95% CI: 1.15–2.84) in women who smoked more than 20 pack-years, compared to non-smokers. Odds ratio of MS was 1.56 (95% CI: 1.25–1.95) in women who had familial history of diseases, including hypertension, diabetes and stroke, compared to women without familial history of those diseases.

Conclusion

MS is highly prevalent among women in rural China. Both physical activity and rice wine consumption play a protective role, while family history and smoking are risk factors in MS development. Educational programs should be established for promoting healthy lifestyles and appropriate interventions in rural China.

No association of genetic polymorphisms in CYP1B1 with primary open-angle glaucoma: a meta- and gene-based analysis

PURPOSE

To examine the effects of genetic polymorphisms in cytochrome P450, subfamily 1, polypeptide 1 (C1P1B1) on primary open-angle glaucoma (POAG).

METHODS

A systematic literature search was performed, and random-effects meta-analyses were used to evaluate genetic polymorphisms in CYP1B1 with POAG. A gene-based analysis was conducted to investigate the cumulative effects of genetic polymorphisms in CYP1B1.

RESULTS

A total of six studies from published papers were included in our analysis. Random-effects meta-analyses failed to detect any significant association of POAG with genetic polymorphisms in CYP1B1, including rs180040, rs1056836, rs10012, rs1056827, rs1056837, and rs2567206. The gene-based analysis indicated that the cumulative effect of genetic polymorphisms in CYP1B1 is not associated with POAG (p>0.50).

CONCLUSIONS

We did not find any evidence of strong association of POAG with CYP1B1 genetic polymorphisms and their cumulative effect.

Association between FTO gene polymorphism and cancer risk: evidence from 16,277 cases and 31,153 controls

A recent genome-wide association study showed that the rs9939609 polymorphism in the fat mass and obesity-associated (FTO) gene was associated with body mass index (BMI)/obesity in Europeans. Subsequently, several studies have investigated the association between FTO polymorphism and cancer risk. However, the results have been inconsistent. In this study, a meta-analysis was performed to clarify the association between FTO polymorphism and cancer risk. Published literature from PubMed and Embase databases were retrieved. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed-effects model. A total of 13 studies involving 16,277 cases and 31,153 controls were identified. The results suggested that FTO rs9939609 polymorphism was not significantly associated with the increased risk of cancer (OR = 1.01, 95 %CI 0.98-1.04), with the exception that a statistically significant association was found for pancreatic cancer (OR = 1.10, 95 %CI 1.03-1.19). No publication bias was detected (Begg's test: P = 0.760; Egger's test: P = 0.553). Our meta-analysis indicated that there was no association between FTO rs9939609 polymorphism and the increased risk of cancer, although this polymorphism was marginally associated with pancreatic cancer. However, the conclusion should be made with caution since most included studies did not take BMI/obesity into account.