Variations in the HHEX gene are associated with increased risk of type 2 diabetes in the Japanese population

Association between FTO gene polymorphism and obesity in down syndrome children

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

CONCLUSION

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

WHAT IS KNOWN

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

WHAT IS NEW

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

CRISPR screening uncovers a long-range enhancer for ONECUT1 in pancreatic differentiation and links a diabetes risk variant

Functional enhancer annotation is critical for understanding tissue-specific transcriptional regulation and prioritizing disease-associated non-coding variants. However, unbiased enhancer discovery in disease-relevant contexts remains challenging. To identify enhancers pertinent to diabetes, we conducted a CRISPR interference (CRISPRi) screen in the human pluripotent stem cell (hPSC) pancreatic differentiation system. Among the enhancers identified, we focused on an enhancer we named ONECUT1e-664kb, ∼664 kb from the ONECUT1 promoter. Previous studies have linked ONECUT1 coding mutations to pancreatic hypoplasia and neonatal diabetes. We found that homozygous deletion of ONECUT1e-664kb in hPSCs leads to a near-complete loss of ONECUT1 expression and impaired pancreatic differentiation. ONECUT1e-664kb contains a type 2 diabetes-associated variant (rs528350911) disrupting a GATA motif. Introducing the risk variant into hPSCs reduced binding of key pancreatic transcription factors (GATA4, GATA6, and FOXA2), supporting its causal role in diabetes. This work highlights the utility of unbiased enhancer discovery in disease-relevant settings for understanding monogenic and complex disease.

Investigation of genetic markers associated to type 2 diabetes mellitus in Santarém-Pará

Genetic, epigenetic and environmental factors play an important role in the genesis of Type 2 Diabetes Mellitus (T2D). In the genetic context, one of the strategies used to investigate possible associations with diabetes is the search for Single Nucleotide Polymorphisms (SNPs), involving the comparison of alelle frequencies, the phenotypic variations and other relevant factors, such as environmental influences and lifestyle choices, Thus, the aim of this study was to find the relationship of risk variants for T2D in SNPs (rs4994) in the ADRB3 gene; (rs1799854) in the ABCC8 gene; (rs7901695 and rs12255372) in the TCF7L2 gene; and (rs8050136) in the FTO gene in a sample of the population of the municipality of Santarém (PA), Brazilian Amazon, in the northern region of Brazil. ABCC8 (rs1799854 C>T) showed a statistically significant association with T2D. Each chosen gene and SNP has been previously implicated in T2D risk according to existing scientific literature, owing to their roles in glucose regulation and body fat.

Causal relationship between type 2 diabetes and common respiratory system diseases: a two-sample Mendelian randomization analysis

Background

Type 2 diabetes (T2D) frequently co-occurs with respiratory system diseases such as chronic obstructive pulmonary disease (COPD), bronchial asthma, lung cancer, interstitial lung disease, and pulmonary tuberculosis. Although a potential association is noted between these conditions, the available research is limited.

Objective

To investigate the causal relationship between patients with T2D and respiratory system diseases using two-sample Mendelian randomization analysis.

Methods

Causal relationships were inferred using a two-sample Mendelian randomization (MR) analysis based on publicly available genome-wide association studies. We employed the variance inverse-weighted method as the primary analytical approach based on three key assumptions underlying MR analysis. To bolster the robustness and reliability of our results, we utilized MR Egger's intercept test to detect potential pleiotropy, Cochran's Q test to assess heterogeneity, funnel plots to visualize potential bias, and "leave-one-out" sensitivity analysis to ensure that our findings were not unduly influenced by any single genetic variant.

Result

The inverse variance weighted (IVW) analysis indicated a causal relationship between T2D and COPD [Odds Ratio (OR) = 0.87; 95% Confidence Interval (CI) = 0.82-0.96; p < 0.05]. No significant heterogeneity or pleiotropy were observed through their respective tests (p > 0.05), and the statistical power calculations indicated that the results were reliable. The IVW analysis showed a negative causal relationship between T2D and bronchial asthma [OR = 0.85; 95% CI = 0.81-0.89; p < 0.05]. However, the IVW under the random-effects model indicated heterogeneity (p < 0.05), suggesting instability in the results and requiring cautious interpretation. The study found a positive causal relationship between T2D and pulmonary tuberculosis (OR = 1.24, 95% CI = 1.05-1.45, p < 0.05). However, they exhibited pleiotropy (p < 0.05), indicating their instability. No correlation between T2D and interstitial lung disease or lung cancer was observed.

Conclusion

T2D is negatively associated with COPD, suggesting that T2D may reduce the risk of developing COPD. A negative causal relationship between T2D and bronchial asthma has been observed, but the results exhibit heterogeneity. There is a positive causal relationship between T2D and pulmonary tuberculosis, yet the findings suggest the presence of pleiotropy. No significant causal relationship between T2D and lung cancer or interstitial lung disease was observed.

CRISPR Screening Uncovers a Long-Range Enhancer for ONECUT1 in Pancreatic Differentiation and Links a Diabetes Risk Variant

Functional enhancer annotation is a valuable first step for understanding tissue-specific transcriptional regulation and prioritizing disease-associated non-coding variants for investigation. However, unbiased enhancer discovery in physiologically relevant contexts remains a major challenge. To discover regulatory elements pertinent to diabetes, we conducted a CRISPR interference screen in the human pluripotent stem cell (hPSC) pancreatic differentiation system. Among the enhancers uncovered, we focused on a long-range enhancer ∼664 kb from the ONECUT1 promoter, since coding mutations in ONECUT1 cause pancreatic hypoplasia and neonatal diabetes. Homozygous enhancer deletion in hPSCs was associated with a near-complete loss of ONECUT1 gene expression and compromised pancreatic differentiation. This enhancer contains a confidently fine-mapped type 2 diabetes associated variant (rs528350911) which disrupts a GATA motif. Introduction of the risk variant into hPSCs revealed substantially reduced binding of key pancreatic transcription factors (GATA4, GATA6 and FOXA2) on the edited allele, accompanied by a slight reduction of ONECUT1 transcription, supporting a causal role for this risk variant in metabolic disease. This work expands our knowledge about transcriptional regulation in pancreatic development through the characterization of a long-range enhancer and highlights the utility of enhancer discovery in disease-relevant settings for understanding monogenic and complex disease.

Identification of Potential Plant-Derived Pancreatic Beta-Cell-Directed Agents Using New Custom-Designed Screening Method: Gymnema sylvestre as an Example

BACKGROUND

Folk medicines are attractive therapeutic agents for treating type 2 diabetes mellitus (T2DM). Most plant extracts that have been suggested to restore β-cells function were tested in vivo. Some only have been tested in vitro to determine whether they have a direct effect on β-cells islets of Langerhans. Currently, there are no defined criteria for screening of β-cell-directed plant-based remedies as potential antidiabetic agents.

SUMMARY

In this review, we have identified certain criteria/characteristics that can be used to generate a "screening portfolio" to identify plant extracts as potential β-cell-directed agents for the treatment of T2DM. To validate our screening method, we studied the potential therapeutic efficacy of a Gymnema sylvestre (GS) extract using the screening criteria detailed in the review. Six criteria have been identified and validated using OSA®, a GS extract. By using this screening method, we show that OSA® fulfilled most of the criteria identified for an effective β-cell-directed antidiabetic therapy, being an effective insulin-releasing agent at nontoxic concentrations; maintaining β-cell insulin content by stimulating a concomitant increase in insulin gene transcription; maintaining β-cell mass by protecting against apoptosis; and being effective at maintaining normoglycemia in vivo in a mouse model and a human cohort with T2DM.

KEY MESSAGES

The present review has highlighted the importance of having a screening portfolio for plant extracts that have potential antidiabetic effects in the treatment of T2DM. We propose that this screening method should be adopted for future studies to identify new β-cell-directed antidiabetic plant derived agents.

FTO gene variants (rs9939609, rs8050136 and rs17817449) and type 2 diabetes mellitus risk: A Meta-Analysis

BACKGROUND AND AIMS

There is tremendous increase in type 2 diabetes mellitus (T2DM) worldwide. The impact of FTO gene polymorphisms on the risk of T2DM is not yet clear because of the controversial results of studies. This meta-analysis aimed to better clarify the association between three FTO gene polymorphisms SNPs (rs9939609, rs8050136 and rs17817449) and T2DM in a larger combined population worldwide.

MATERIAL AND METHODS

A comprehensive search on the PubMed, Science Direct, and Web of Science databases was conducted to identify investigations in relationship between different FTO gene polymorphisms (rs9939609, rs8050136 and rs17817449) and T2DM globally. Published papers from January 2007 to May 2023 were collected. Inclusion criteria are limited to human case-control studies published in English and peer-reviewed, which provided data on the genotype distributions of FTO gene polymorphisms and T2DM risk. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to express the results of the meta-analysis. Potential sources of bias and heterogeneity using Egger's regression analysis were also assessed.

RESULTS

Of 234695 identified articles, forty-eight studies were selected including 36,051 patients with T2DM and 51,266 control subjects. Overall, we found a significant increased risk of T2DM susceptibility and rs9939609 FTO gene polymorphism in the Allele contrast (A vs. T: OR = 1,30, 95% CI = 1.14; 1.48, P < 0,05, I2 = 0,94), Recessive model (AA vs. AT + TT: OR = 1,54, 95% CI = 1.19; 2.00, P < 0,05, I2 = 0,94), Dominant model (AA + AT vs. TT: OR = 1,26, 95% CI = 1.10; 1.45, P < 0,05, I2 = 0,89), homozygote model (AA vs. TT: OR = 1,60, 95% CI = 1.26; 2.03, P < 0,05, I2 = 0,90), and heterozygote model (AA vs. AT: OR = 1,43, 95% CI = 1.09; 1.88, P = 0,008, I2 = 0,93). we also found a significantly increased risk of T2DM susceptibility and rs8050136 FTO gene polymorphism under all models. For rs17817449 we did not find any association between with T2DM.

CONCLUSION

The present meta-analysis confirms that rs9939609 and rs8050136 in the FTO gene are significantly associated with T2DM, while rs17817449 does not show any association.

Type 2 diabetes linked FTO gene variant rs8050136 is significantly associated with gravidity in gestational diabetes in a sample of Bangladeshi women: Meta-analysis and case-control study

OBJECTIVE

Gestational diabetes mellitus (GDM) is a growing public health concern that has not been extensively studied. Numerous studies have indicated that a variant (rs8050136) of the fat mass-associated gene, FTO, is associated with both GDM and Type 2 diabetes mellitus(T2DM). We conducted a meta-analysis on the association between the FTO single nucleotide polymorphism (SNP) rs8050136 and T2DM, followed by a case-control study on the association of the said SNP and GDM in a sample of Bangladeshi women.

METHOD

A total of 25 studies were selected after exploring various databases and search engines, which were assessed using the Newcastle-Ottawa Scale (NOS). The MetaGenyo web tool was used to conduct this meta-analysis. A case-control study was performed on 218 GDM patients and 284 controls to observe any association between FTO rs8050136 and GDM. Genotyping was performed using the tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS) method, and statistical analyses were performed using various statistical softwares.

RESULTS

In the meta-analysis 26231 cases and 43839 controls were examined. Pooled association analyses revealed a statistically significant relationship between the FTO rs8050136 polymorphism and an elevated risk of T2DM under all genetic models (P<0.05). In the case-control study, synergistic analyses of the SNP and gravida with GDM revealed a significant (P<0.01) association with an increase in odds by 1.6 to 2.4 folds in multigravida and decrease in odds by 2 folds in primigravida. A positive family history of diabetes and the minor allele of this SNP collectively increased the risk of developing GDM by many-fold (1.8 to 2.7 folds). However, after accounting for family history of diabetes and gravidity, analyses showed no significant association with GDM.

CONCLUSION

Our meta-analysis revealed a significant association between SNP rs8050136 of FTO with T2DM, and this variant was substantially associated with an increased risk of GDM in a sample of Bangladeshi multigravida women.

Elucidation of HHEX in pancreatic endoderm differentiation using a human iPSC differentiation model

For pluripotent stem cell (PSC)-based regenerative therapy against diabetes, the differentiation efficiency to pancreatic lineage cells needs to be improved based on the mechanistic understanding of pancreatic differentiation. Here, we aimed to elucidate the molecular mechanisms underlying pancreatic endoderm differentiation by searching for factors that regulate a crucial pancreatic endoderm marker gene, NKX6.1. Unbiasedly screening an siRNA knockdown library, we identified a candidate transcription factor, HHEX. HHEX knockdown suppressed the expression of another pancreatic endoderm marker gene, PTF1A, as well as NKX6.1, independently of PDX1, a known regulator of NKX6.1 expression. In contrast, the overexpression of HHEX upregulated the expressions of NKX6.1 and PTF1A. RNA-seq analysis showed decreased expressions of several genes related to pancreatic development, such as NKX6.1, PTF1A, ONECUT1 and ONECUT3, in HHEX knockdown pancreatic endoderm. These results suggest that HHEX plays a key role in pancreatic endoderm differentiation.

Association between fat mass and obesity-related variant and osteoarthritis risk: Integrated meta-analysis with bioinformatics

Objective

The association of fat mass and obesity-related (FTO) gene with osteoarthritis (OA) risk has been investigated in multiple genome-wide association studies but showed inconsistent results. Our study aimed to assess FTO expression in different OA sequencing datasets and to meta-analyze whether FTO polymorphism was associated with the risk of osteoarthritis.

Method

Gene expression profiles were obtained from ArrayExpress, Gene Expression Omnibus (GEO), and BioProject databases. Three electronic databases including PubMed and EMBASE were systematically retrieved to identify articles exploring the association between FTO polymorphisms and OA risk published before September 2022. Summary odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated to perform the result. Stata software was utilized to conduct analyses on predetermined ethnicity and gender subgroups and sensitivity.

Results

FTO gene was differentially expressed in the datasets from the UK. This systematic review and meta-analysis encompasses eight studies that revealed a significant association between FTO polymorphisms and OA risk [OR 1.07, 95% CI (1.03, 1.11), P < 0.001] in the overall population. In subgroup analysis, a marked association was observed in European Caucasian [OR 1.08, 95% CI (1.04–1.12), P < 0.001] and North American Caucasian with the Asian subgroups [OR 0.98, 95% CI (0.83–1. 6), P = 0.83] as an exception. Among the studies, four of them demonstrated attenuation in their OA risk after body mass index (BMI) adjustment in Caucasian populations.

Conclusion

FTO significant differential expression was associated with the increased risk of OA in Caucasian populations. Nevertheless, the causality between FTO polymorphisms and OA risk remains largely elusive. Hence, further studies with larger sample size are necessary to validate whether FTO gene polymorphism contributes to OA susceptibility.

Emerging Roles of FTO in Neuropsychiatric Disorders

FTO (fat mass and obesity associated) is a recently discovered gene related to obesity and expressed in various tissues of the human body, especially with high expression in the brain. Earlier studies have found that FTO is involved in several biological processes, including brain development and function. In particular, recent studies have found that FTO is a demethylase of N6-methyladenosine (m6A) and it can affect neurological function through the m6A modification of mRNA. At present, a number of studies have shown that FTO is associated with many neuropsychiatric disorders. This paper reviews the discovery, structure, function, and tissue expression of FTO followed by discussing the relationship between FTO and neuropsychiatric diseases. In addition, the potential roles of FTO gene in drug addiction, major depression (MDD), and schizophrenia (SCZ) through regulating m6A modification of dopamine related genes were also highlighted.

Contribution of genetic variant identified in HHEX gene in the overweight Saudi patients confirmed with type 2 diabetes mellitus

Background

The rs7932837 polymorphism in the Hematopoietically expressed homeobox (HHEX) gene was discovered through genome-wide association studies and is a promising candidate for type 2 diabetes mellitus (T2DM), which is one of the risk factors for obesity and other complications. T2DM has been identified as a heterogeneous and multifactorial disease characterized by insulin resistance and secretion.

Aim

The aim of this study was to investigate the rs7932837 polymorphism in the HHEX gene in overweight patients diagnosed with T2DM in the Saudi Population.

Methods

In this case-control study, one hundred T2DM cases and 100 controls were selected based on inclusion and exclusion criteria. Genotyping was performed with polymerase chair reaction-restriction fragment length polymorphism analysis and statistical analysis was performed between T2DM cases and controls for clinical characteristics, genotype and allele frequencies and multiple logistic regression analysis.

Results

In this study, T2DM cases were compared with healthy control subjects. Clinical characteristic analysis revealed the statistical analysis between age, weight, BMI, FBG, HDL-c, TC, TG and family history (p < 0.05). HWE analysis was in the accordance (p < 0.05). The rs7932837 polymorphism in the recessive model showed the positive association (AA + AG vs AA: 2.22 [1.25–3.96] & p = 0.006) and none of the genotypes or alleles were in the statistical association. Multiple logistic regression analysis revealed positive association with age, BMI and FBG (p < 0.05).

Conclusion

This study concludes as rs7932837 polymorphism in the HHEX gene showed positive association with recessive model and future studies recommend to carry out with large number of sample size with additional polymorphisms in HHEX gene.

Association of fat mass and obesity-associated (FTO) gene rs9939609 with obesity-related traits and glucose intolerance in an indigenous population, the Xavante

BACKGROUND AND AIMS

Common variants in fat mass and obesity-associated (FTO) gene have been implicated as a susceptibility locus for obesity and type 2 diabetes in different populations. Here, in an indigenous population-based study, we examined whether FTO rs9939609 has a role in susceptibility to glucose intolerance and obesity.

METHODS

The study population comprised 949 full Xavante indigenous people (465 men) aged 18-99 years. The participants were submitted to clinical examination, anthropometrical measures and basal and 2-h post 75g oral glucose load capillary glucose measurements. FTO rs9939609 was genotyped and logistic regression was carried out to test the additive effect of the risk allele.

RESULTS

The frequency of the minor allele of the FTO rs9939609 (0.06) was lower in Xavante than observed in some populations. A significant association between the variant and overweight was observed (OR = 1.56 (95% CI:1.06-2.29, p = 0.02), using an additive model of inheritance, adjusted by age and gender and considering the family structure. We found no associations with obesity or glucose intolerance.

CONCLUSIONS

The FTO rs9939609 is associated with overweight, but not with obesity or glucose intolerance. The low frequency of the A allele suggests that it is not an important risk determinant for these conditions in Xavante indigenous people.

Genetic risk factors associated with gestational diabetes in a multi-ethnic population

AIMS

Genome-wide association studies have shown an increased risk of type-2-diabetes (T2DM) in patients who carry single nucleotide polymorphisms in several genes. We investigated whether the same gene loci confer a risk for gestational diabetes mellitus (GDM) in women from Hawaii, and in particular, Pacific Islander and Filipino populations.

METHODS

Blood was collected from 291 women with GDM and 734 matched non-diabetic controls (Pacific Islanders: 71 GDM, 197 non-diabetic controls; Filipinos: 162 GDM, 395 controls; Japanese: 58 GDM, 142 controls). Maternal DNA was used to genotype and show allele frequencies of 25 different SNPs mapped to 18 different loci.

RESULTS

After adjusting for age, BMI, parity and gravidity by multivariable logistic regression, several SNPs showed significant associations with GDM and were ethnicity specific. In particular, SNPs rs1113132 (EXT2), rs1111875 (HHEX), rs2237892 (KCNQ1), rs2237895 (KCNQ1), rs10830963 (MTNR1B) and rs13266634 (SLC30A8) showed significant associations with GDM in Filipinos. For Japanese, SNPs rs4402960 (IGFBP2) and rs2237892 (KCNQ1) were significantly associated with GDM. For Pacific Islanders, SNPs rs10830963 (MTNR1B) and rs13266634 (SLC30A8) showed significant associations with GDM. Individually, none of the SNPs showed a consistent association with GDM across all three investigated ethnicities.

CONCLUSION

Several SNPs associated with T2DM are found to confer increased risk for GDM in a multiethnic cohort in Hawaii.

Diabetes and Renin-Angiotensin-Aldosterone System: Pathophysiology and Genetics

Diabetes mellitus (DM) is a metabolic disorder and characterized by hyperglycemia. Being a concern of both the developed and developing world, diabetes is a global health burden and is a major cause of mortality world-wide. The most common is the type 2 diabetes mellitus (T2DM), which is mainly caused by resistance to insulin. Long-term complications of diabetes cause microvascular related problems (eg. nephropathy, neuropathy and retinopathy) along with macrovascular complications (eg. cardiovascular diseases, ischemic heart disease, peripheral vascular disease). Renin-angiotensin-aldosterone system (RAAS) regulates homeostasis of body fluid that in turn, maintains blood pressure. Thus, RAAS plays pivotal role in the pathogenesis of long-term DM complications like cardiovascular diseases and chronic kidney diseases. T2DM is a polygenic disease, and the roles of RAAS components in insulin signaling pathway and insulin resistance have been well documented. Hyperglycemia has been found to be associated with the increased plasma renin activity, arterial pressure and renal vascular resistance. Several studies have reported involvement of single variants within particular genes in initiation and development of T2D using different approaches. This chapter aims to investigate and discuss potential genetic polymorphisms underlying T2D identified through candidate gene studies, genetic linkage studies, genome wide association studies.

Association between FTO (rs17817449) genetic variant, gamma-glutamyl transferase, and hypertension in Slovak midlife women

OBJECTIVES

This cross-sectional study investigates associations between the FTO rs 17817449 genetic variant, liver enzymes, and hypertension in Slovak midlife women.

METHODS

We assessed 576 Slovak women aged 39 to 65 years. The women were interviewed and examined during their medical examination at local Health Centers and then divided into subgroups according to their blood pressure status; 255 women with hypertension and 321 normotensive. The FTO genetic variant was detected by polymerase chain reaction-restriction fragment length polymorphism. Resultant data was analyzed by linear regression analysis and general linear models to adjust for risk factors associated with gamma-glutamyl transferase levels (GGT), including waist to hip ratio (WHR) and uric acid (UA).

RESULTS

A significant association between the FTO variant and GGT levels was observed in the hypertensive group after control for confounding covariates, including WHR and UA (p = .004). The predicted GGT level for GT/TT hypertensive carriers is 0.158 μkat/L higher than for GG carriers. Moreover, the two-way analysis of covariance revealed significant interaction between FTO effects and hypertension on logGGT levels (p = .042). Finally, hypertensive women with the T-allele had the highest estimated marginal mean value of logGGT at -0.39 μkat/L while the GG-genotype in both hypertensive and normotensive women had the lowest value at -0.54 μkat/L.

CONCLUSIONS

This study suggests that the FTO (rs17817449) variant is associated with higher serum GGT levels in hypertensive midlife women.

Interaction between dietary branched-chain amino acids and genetic risk score on the risk of type 2 diabetes in Chinese

BACKGROUND AND OBJECTIVES

Previous studies have found the important gene-diet interactions on type 2 diabetes (T2D) incident but have not followed branched-chain amino acids (BCAAs), even though they have shown heterogeneous effectiveness in diabetes-related factors. So in this study, we aim to investigate whether dietary BCAAs interact with the genetic predisposition in relation to T2D risk and fasting glucose in Chinese adults.

METHODS

In a case-control study nested in the Harbin Cohort Study on Diet, Nutrition and Chronic Non-Communicable Diseases, we obtained data for 434 incident T2D cases and 434 controls matched by age and sex. An unweighted genetic risk score (GRS) was calculated for 25 T2D-related single nucleotide polymorphisms by summation of the number of risk alleles for T2D. Multivariate logistic regression models and general linear regression models were used to assess the interaction between dietary BCAAs and GRS on T2D risk and fasting glucose.

RESULTS

Significant interactions were found between GRS and dietary BCAAs on T2D risk and fasting glucose (p for interaction = 0.001 and 0.004, respectively). Comparing with low GRS, the odds ratio of T2D in high GRS were 2.98 (95% CI 1.54-5.76) among those with the highest tertile of total BCAA intake but were non-significant among those with the lowest intake, corresponding to 0.39 (0.12) mmol/L versus - 0.07 (0.10) mmol/L fasting glucose elevation per tertile. Viewed differently, comparing extreme tertiles of dietary BCAAs, the odds ratio (95% CIs) of T2D risk were 0.46 (0.22-0.95), 2.22 (1.15-4.31), and 2.90 (1.54-5.47) (fasting glucose elevation per tertile: - 0.23 (0.10), 0.18 (0.10), and 0.26 (0.13) mmol/L) among participants with low, intermediate, and high genetic risk, respectively.

CONCLUSIONS

This study indicated that dietary BCAAs could amplify the genetic association with T2D risk and fasting glucose. Moreover, higher BCAA intake showed positive association with T2D when genetic predisposition was also high but changed to negative when genetic predisposition was low.

Association of CDKAL1 RS10946398 Gene Polymorphism with Susceptibility to Diabetes Mellitus Type 2: A Meta-Analysis

BACKGROUND

Diabetes is one of the common chronic diseases in which susceptibility is determined by a combination of genetic and environmental factors, and more than 90% of diabetic patients are diabetes mellitus type 2 (T2DM). The existing studies on the association between CDKAL1 rs10946398 gene polymorphism and susceptibility to type 2 diabetes are inconsistent across populations.

AIM

We aim to explore the association between CDKAL1 rs10946398 gene polymorphism and susceptibility to type 2 diabetes in different populations.

METHODS

We examined all studies before June 12, 2021, that associated CDKAL1 rs10946398 with T2DM. Heterogeneity was assessed by meta-analysis of allelic inheritance models (A vs. C), dominant inheritance models (AA vs. AC+CC), and recessive inheritance model (AA+AC vs. CC); I ² was used to assess the heterogeneity (if I ² < 50%, the fixed-effects model was used; if I ² ≥ 50%, the random-effects model was used for data consolidation); correlation was judged by a forest map; potential publication bias was tested by the Egger test (p > 0.05 indicates that there is no publication bias).

RESULTS

Fourteen data totaling 30288 subjects, including 19272 controls and 11016 patients with T2DM, met our inclusion criteria. In the Asian population, the differences were statistically significant (p < 0.01) for dominant genetic model (OR = 0.75, 95%CI = 0.64-0.88, p = 0.0003). But the allelic effect model (OR = 0.87, 95%CI = 0.75-1.02, p = 0.08) and the recessive genetic model (OR = 0.85, 95%CI = 0.66-1.10, p = 0.23) were not statistically significant (p > 0.01). In the non-Asian population, the differences were statistically significant (p < 0.01) for the allelic effect model (OR = 0.83, 95%CI = 0.77-0.88, p < 0.00001), the dominant model (OR = 0.79, 95%CI = 0.72-0.87, p < 0.00001), and the recessive model (OR = 0.78, 95%CI = 0.70-0.87, p < 0.0001).

CONCLUSION

In this study, CDKAL1 RS10946398 was positively associated with T2DM, but the association was different in Asian populations.

Impact of type 2 diabetes variants identified through genome-wide association studies in early-onset type 2 diabetes from South Indian population

The prevalence of early-onset type 2 diabetes (EOT2D) is increasing in Asian countries. Genome-wide association studies performed in European and various other populations have identified associations of numerous variants with type 2 diabetes in adults. However, the genetic component of EOT2D which is still unexplored could have similarities with late-onset type 2 diabetes. Here in the present study we aim to identify the association of variants with EOT2D in South Indian population. Twenty-five variants from 18 gene loci were genotyped in 1,188 EOT2D and 1,183 normal glucose tolerant subjects using the MassARRAY technology. We confirm the association of the HHEX variant rs1111875 with EOT2D in this South Indian population and also the association of CDKN2A/2B (rs7020996) and TCF7L2 (rs4506565) with EOT2D. Logistic regression analyses of the TCF7L2 variant rs4506565(A/T), showed that the heterozygous and homozygous carriers for allele ‘T’ have odds ratios of 1.47 (95% confidence interval [CI], 1.17 to 1.83; p = 0.001) and 1.65 (95% CI, 1.18 to 2.28; p = 0.006) respectively, relative to AA homozygote. For the HHEX variant rs1111875 (T/C), heterozygous and homozygous carriers for allele ‘C’ have odds ratios of 1.13 (95% CI, 0.91 to 1.42; p = 0.27) and 1.58 (95% CI, 1.17 to 2.12; p = 0.003) respectively, relative to the TT homozygote. For CDKN2A/2B variant rs7020996, the heterozygous and homozygous carriers of allele ‘C’ were protective with odds ratios of 0.65 (95% CI, 0.51 to 0.83; p = 0.0004) and 0.62 (95% CI, 0.27 to 1.39; p = 0.24) respectively, relative to TT homozygote. This is the first study to report on the association of HHEX variant rs1111875 with EOT2D in this population.

The interaction between FTO rs9939609 and physical activity is associated with a 2-fold reduction in the risk of obesity in Korean population

OBJECTIVE

FTO (fat mass and obesity-associated) gene is a well-known genetic risk factor for obesity. We investigated whether physical activity modulates the effect of FTO rs9939609 on obesity in Korean population.

METHODS

The study analyzed the correlation between physical activity and obesity in 8840 individuals representing the Korea Association Resource (KARE). The association between obesity-related traits and single-nucleotide polymorphisms (SNPs) was assessed using linear regression models. Physical activity was defined as 3 hours or more of daily intense activity.

RESULTS

Participants carrying rs9939609 (AT+AA) genotypes showed higher BMI compared with those carrying the wild-type (TT) homozygote. The highest significant association was observed between obesity-related traits (ß = .334, P value = 1.76 × 10^-6 ). FTO rs9939609 (AT+AA) increased the risk of obesity (OR = 1.42, CI [1.13-1.79]), which was correlated with BMI correlations. However, active exercise by subjects carrying the same genotype reduced the risk of obesity by nearly 2-fold (OR = 0.62, CI [0.25-0.84]). In contrast, TT genotype was not statistically significant in reducing the risk of obesity in the active exercise group.

CONCLUSIONS

Our results support a previous finding correlating FTO and obesity-related traits and suggest that the interaction with genetic variation and physical activity is an important risk factor for obesity.

Insights into pancreatic islet cell dysfunction from type 2 diabetes mellitus genetics

Type 2 diabetes mellitus (T2DM) is an increasingly prevalent multifactorial disease that has both genetic and environmental risk factors, resulting in impaired glucose homeostasis. Genome-wide association studies (GWAS) have identified over 400 genetic signals that are associated with altered risk of T2DM. Human physiology and epigenomic data support a central role for the pancreatic islet in the pathogenesis of T2DM. This Review focuses on the promises and challenges of moving from genetic associations to molecular mechanisms and highlights efforts to identify the causal variant and effector transcripts at T2DM GWAS susceptibility loci. In addition, we examine current human models that are used to study both β-cell development and function, including EndoC-β cell lines and human induced pluripotent stem cell-derived β-like cells. We use examples of four T2DM susceptibility loci (CDKAL1, MTNR1B, SLC30A8 and PAM) to emphasize how a holistic approach involving genetics, physiology, and cellular and developmental biology can disentangle disease mechanisms at T2DM GWAS signals.

Potential role of hypothalamic microRNAs in regulation of FOS and FTO expression in response to hypoglycemia

Hypoglycemia-associated autonomic failure (HAAF) is a serious complication of diabetes which is associated with the absence of physiological homeostatic counter-regulatory mechanisms that are controlled by the hypothalamus and sympathetic nervous system. Identification of biomarkers for early detection of HAAF requires an advanced understanding of molecular signature of hypoglycemia which is yet to be identified. The outcomes of the present study have shown that the viability and the apoptotic rate of the hypothalamic neurons (mHypoE-N39) were decreased significantly due to hypoglycemia in a dose-dependent fashion (p < 0.05). Although there are more than 1000 miRNAs differentially expressed in hypothalamus, only twelve miRNAs (miR-7a, miR-7b, miR-9, miR-29b, miR-29c, miR-30a, miR-30b, miR-30c, miR-101b-3p, miR-181a-5p, miR-378-3p and miR-873-5p) were correlated to two main hypothalamic regulatory proteins, FOS and FTO. Expression of these proteins was very sensitive to hypoglycemia. We demonstrated that hypoglycemia modulates the expression of hypothalamic miRNAs that are related to FOS and FTO.

Fat Mass and Obesity Associated (FTO) Gene and Hepatic Glucose and Lipid Metabolism

Common genetic variants of the fat mass and obesity associated (FTO) gene are strongly associated with obesity and type 2 diabetes. FTO is ubiquitously expressed. Earlier studies have focused on the role of hypothalamic FTO in the regulation of metabolism. However, recent studies suggest that expression of hepatic FTO is regulated by metabolic signals, such as nutrients and hormones, and altered FTO levels in the liver affect glucose and lipid metabolism. This review outlines recent findings on hepatic FTO in the regulation of metabolism, with particular focus on hepatic glucose and lipid metabolism. It is proposed that abnormal activity of hepatic signaling pathways involving FTO links metabolic impairments such as obesity, type 2 diabetes and nonalcoholic fatty liver disease (NAFLD). Therefore, a better understanding of these pathways may lead to therapeutic approaches to treat these metabolic diseases by targeting hepatic FTO. The overall goal of this review is to place FTO within the context of hepatic regulation of metabolism.

FTO, GCKR, CDKAL1 and CDKN2A/B gene polymorphisms and the risk of gestational diabetes mellitus: a meta-analysis

PURPOSE

Studies had examined the associations between genetic polymorphisms and the risk of gestational diabetes mellitus (GDM). However, conclusions of these studies were controversial due to the smaller sample size and limited statistical power. We carried out a meta-analysis with the aim of providing a more comprehensive summary of the currently available research to evaluate the relationship between FTO, GCKR, CDKAL1 and CDKN2A/B gene polymorphisms and GDM risk.

METHODS

Literature search was carried out in the PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure and Wangfang databases up to November 2017. Data were extracted by two independent reviewers and statistical analyses were performed with STATA software. Pooled odds ratios and 95% confidence intervals were calculated by Z test to assess the association between genetic polymorphisms and GDM risk. Stratified analysis was performed based on ethnicity. Heterogeneity and publication bias between studies were evaluated by Cochran's Q test and Egger regression test, respectively.

RESULTS

14 eligible studies were included. CDKAL1 rs7754840 and rs7756992 showed significant correlation with GDM risk under the allele, recessive, dominant, homozygote and heterozygote models. GCKR rs780094 and CDKN2A/B rs10811661 also showed the same association under the allele, recessive and heterozygote models. No associations between FTO rs9939609 and rs8050136, GCKR rs1260326 and GDM risk were found.

CONCLUSIONS

Our meta-analysis showed that two SNPs in particular(rs7754840 and rs7756992 in CDKAL1) were very strongly associated with GDM risk. GCKR rs780094 and CDKN2A/B rs10811661 polymorphisms were moderately associated with GDM risk.

Association between gene polymorphisms and obesity and physical fitness in Korean children

Obesity is affected by genetic factors and environmental influences. This research was undertaken to identify single nucleotide polymorphisms (SNPs) related to obesity and physical fitness and then to analyse and compare interactions between physical fitness and obesity-associated genotypes. To investigate relationships between physical fitness and major SNPs previously reported to be related to obesity, 68 SNPs in 32 genes were genotyped in 71 Korean children. Tests were conducted to evaluate five elements of physical fitness (speed, aerobic endurance, muscular endurance, muscular strength, and flexibility). The results obtained showed significant (P<0.02) differences in physical fitness scores for the following genotypes: CNR1 (rs1049353; GG), LEP (rs7799039; AA+AG), HHEX (rs1111875; TT), GC (rs16847015; TG+GG), LRP5 (rs4988300; GG+GT), NPY2R (rs2880415; CT+CC), PPY (rs231472; GG), UCP2 (rs660339; CT+TT), CDKN2B (rs10811661; AA+AG), and ADIPOQ (rs266729; CG+GG). Ten physical fitness-related genotypes were newly identified during the present study. This study suggests that classification of genotypes by physical fitness level could be used as an index for predicting the risk of obesity and for selecting individuals for intervention programmes. Furthermore, the study shows that even children participating in the same physical fitness improvement programme can exhibit different genotype dependencies.

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.

FTO Genotype and Type 2 Diabetes Mellitus: Spatial Analysis and Meta-Analysis of 62 Case-Control Studies from Different Regions

Type 2 diabetes mellitus (T2DM) is a global health problem that results from the interaction of environmental factors with genetic variants. Although a number of studies have suggested that genetic polymorphisms in the fat mass and obesity-associated (FTO) gene are associated with T2DM risk, the results have been inconsistent. To investigate whether FTO polymorphisms associate with T2DM risk and whether this association is region-related, we performed this spatial analysis and meta-analysis. More than 60,000 T2DM patients and 90,000 controls from 62 case-control studies were included in this study. Odds ratios (ORs), 95% confidence intervals (CIs) and Moran's I statistic were used to estimate the association between FTO rs9939609, rs8050136, rs1421085, and rs17817499, and T2DM risk in different regions. rs9939609 (OR = 1.15, 95% CI 1.11-1.19) and rs8050136 (OR = 1.14, 95% CI 1.10-1.18) conferred a predisposition to T2DM. After adjustment for body mass index (BMI), the association remained statistically significant for rs9939609 (OR = 1.11, 95% CI 1.05-1.17) and rs8050136 (OR = 1.08, 95% CI 1.03-1.12). In the subgroup analysis of rs9939609 and rs8050136, similar results were observed in East Asia, while no association was found in North America. In South Asia, an association for rs9939609 was revealed but not for rs8050136. In addition, no relationship was found with rs1421085 or rs17817499 regardless of adjustment for BMI. Moran's I statistic showed that significant positive spatial autocorrelations existed in rs9939609 and rs8050136. Studies on rs9939609 and rs8050136 focused on East Asia and South Asia, whereas studies on rs1421085 and rs17817499 were distributed in North America and North Africa. Our data suggest that the associations between FTO rs9939609, rs8050136 and T2DM are region-related, and the two single-nucleotide polymorphisms contribute to an increased risk of T2DM. Future studies should investigate this issue in more regions.

Hematopoietically expressed homeobox (HHEX) gene polymorphism (rs5015480) is associated with increased risk of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a metabolic disorder that occurs during pregnancy. HHEX and PROX1 are genetic loci associated with diabetes mellitus type 2. HHEX and PROX1 play significant roles in carbohydrate intolerance and diabetes because these transcription factors may be involved in the regulation of insulin secretion and in glucose and lipid metabolism. The aim of this study was to examine the association between HHEX (rs5015480) and PROX1 (rs340874) gene polymorphisms and GDM. This study included 204 pregnant women with GDM and 207 pregnant women with the normal glucose tolerance (NGT). The diagnosis of GDM was based on a 75-g oral glucose tolerance test at 24-28 weeks' gestation. There was a statistically significant prevalence of the HHEX rs5015480 CC genotype and C allele among women with GDM (C vs T allele, p = 0.021, odds ratio OR = 1.40, 95% CI: 1.05-1.87). Statistically significant higher increase of body mass and BMI during pregnancy was found in women with the HHEX rs5015480 CC genotype. The results of our study suggest an association between the HHEX gene rs5015480 polymorphism and risk of GDM. The HHEX gene rs5015480 C allele may be a risk allele of GDM that is associated with increased BMI during pregnancy.

FTO Gene Polymorphism Is Associated with Type 2 Diabetes through Its Effect on Increasing the Maximum BMI in Japanese Men

Aim

Several studies have demonstrated that polymorphisms within the fat-mass and obesity-associated gene (FTO) are associated with type 2 diabetes (T2D). However, whether the effects of the FTO locus on T2D susceptibility are independent of fat-mass increases remains controversial. To investigate this issue, we examined the association of FTO variants with T2D and various aspects of BMI history during adult life in a Japanese population.

Methods

We genotyped SNPs within FTO (rs1121980 and rs1558902) in 760 Japanese patients with T2D who had reached a lifetime maximum BMI (BMI_max) before or at the time of diagnosis and 693 control individuals with information regarding their BMI_max.

Results

The BMI_max showed the strongest association with T2D risk among the BMIs evaluated in this study. In the sex-combined analysis, FTO SNPs were not associated with any of the BMI variables or with T2D, but in sex-stratified analyses, both SNPs were significantly associated with the BMI_max and rs1558902 was associated with T2D in men. The association of the SNPs with T2D remained significant after adjustments for the current BMI and age, whereas the T2D association of the SNP was no longer significant after adjustments for BMI_max and age.

Conclusions

These results suggest that the effects of FTO polymorphisms on T2D susceptibility in Japanese men are mediated through their effect on increasing the BMI_max before or at the time of diagnosis.

Association of SLC30A8 gene polymorphism with type 2 diabetes, evidence from 46 studies: a meta-analysis

The solute carrier family 30 member 8 (SLC30A8) gene may be involved in the development of type 2 diabetes mellitus (T2DM) through disrupting β-cell function. The aim of this study was to assess the association between SLC30A8 rs13266634 polymorphism and susceptibility to T2DM. We searched all reports regarding the association between SLC30A8 rs13266634 polymorphism and T2DM risk through Pubmed, Embase, and the Cochrane Library for English language reports and Chongqing VIP database, Wanfang data, CBMDisc, and CNKI for Chinese language studies. Allelic and genotype comparisons between cases and controls were evaluated, and odds ratios with 95 % confidence intervals were used to assess the strength of their association. A random effects model was selected. Publication bias was estimated using Begg's test. Forty-six studies were included in the analysis with a total of 71,890 cases and 96,753 controls. This meta-analysis suggests that SLC30A8 (rs13266634) polymorphism was associated with T2DM risk. Although previous meta-analyses have shown that this association was only found in Asian and European groups, and not in African populations, our analysis revealed the deleterious effect of SLC30A8 rs13266634 on T2DM in an African population when stratified by ethnicity under additive model even with a small number of studies.

Association between IGF2BP2 Polymorphisms and Type 2 Diabetes Mellitus: A Case-Control Study and Meta-Analysis

Background: Genome-wide association studies (GWAS) found that IGF2BP2 rs4402960 and rs1470579 polymorphisms were associated with type 2 diabetes mellitus (T2DM) risk. Many studies have replicated this association, but yielded inconsistent results. Materials and Methods: A case-control study consisting of 461 T2DM patients and 434 health controls was conducted to detect the genetic susceptibility of IGF2BP2 in a northern Han Chinese population. A meta-analysis was to evaluate the association more precisely in Asians. Results: In the case-control study, the carriers of TT genotype at rs4402960 had a higher T2DM risk than the G carriers (TG + GG) (adjusted odd ratio (AOR) = 1.962, 95% confidence interval (95% CI) = 1.065–3.612, p = 0.031]; CC carriers at rs1470579 were more susceptible to T2DM than A carriers (CA + AA) (AOR = 2.014, 95% CI = 1.114–3.642, p = 0.021). The meta-analysis containing 36 studies demonstrated that the two polymorphisms were associated with T2DM under the allele comparison, genetic models of dominant and recessive in Asians (p < 0.05). The rs4402960 polymorphisms were significantly associated with the T2DM risk after stratification by diagnostic criterion, size of sample and average age and BMI of cases, while there’re no consistent results for rs1470579. Conclusions: Our data suggests that IGF2BP2 polymorphisms are associated with T2DM in Asian populations.

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.

Gene Polymorphism Association with Type 2 Diabetes and Related Gene-Gene and Gene-Environment Interactions in a Uyghur Population

BACKGROUND We investigated the association between 8 single-nucleotide polymorphisms (SNPs) at 3 genetic loci (CDKAL1, CDKN2A/2B and FTO) with type 2 diabetes (T2D) in a Uyghur population. MATERIAL AND METHODS A case-control study of 879 Uyghur patients with T2D and 895 non-diabetic Uyghur controls was conducted at the Hospital of Xinjiang Medical University between 2010 and 2013. Eight SNPs in CDKAL1, CDKN2A/2B and FTO were analyzed using Sequenom MassARRAY®SNP genotyping. Factors associated with T2D were assessed by logistic regression analyses. Gene-gene and gene-environment interactions were analyzed by generalized multifactor dimensionality reduction. RESULTS Genotype distributions of rs10811661 (CDKN2A/2B), rs7195539, rs8050136, and rs9939609 (FTO) and allele frequencies of rs8050136 and rs9939609 differed significantly between diabetes and control groups (all P<0.05). While rs10811661, rs8050136, and rs9939609 were eliminated after adjusting for covariates (P>0.05), rs7195539 distribution differed significantly in co-dominant and dominant models (P<0.05). In gene-gene interaction analysis, after adjusting for covariates the two-locus rs10811661-rs7195539 interaction model had a cross-validation consistency of 10/10 and the highest balanced accuracy of 0.5483 (P=0.014). In gene-environment interaction analysis, the 3-locus interaction model TG-HDL-family history of diabetes had a cross-validation consistency of 10/10 and the highest balanced accuracy of 0.7072 (P<0.001). The 4-locus interaction model, rs7195539-TG-HDL-family history of diabetes had a cross-validation consistency of 8/10 (P<0.001). CONCLUSIONS Polymorphisms in CDKN2A/2B and FTO, but not CDKAL1, may be associated with T2D, and alleles rs8050136 and rs9939609 are likely risk alleles for T2D in this population. There were potential interactions among CDKN2A/2B (rs10811661) - FTO (rs7195539) or FTO (rs7195539)-TG-HDL-family history of diabetes in the pathogenesis of T2D in a Uyghur population.

Maternal and neonatal FTO rs9939609 polymorphism affect insulin sensitivity markers and lipoprotein profile at birth in appropriate-for-gestational-age term neonates

The influence of maternal fat mass and obesity (FTO) gene polymorphism on neonatal insulin sensitivity/resistance biomarkers and lipoprotein profile has not been tested. The study aimed to assess the association between the FTO rs9939609 polymorphism in mother-neonate couples and neonatal anthropometrical measurements, insulin sensitivity/resistance, and lipid and lipoprotein concentrations at birth. Fifty-three term, appropriate-for-gestational-age, Caucasian newborns together with their respective mothers participated in a cross-sectional study. Sixty-six percent of mothers and neonates carried the A allele (being AA or AT). TT mothers gained less weight during pregnancy, but non-significant maternal gene influence was found for neonatal bodyweight, body mass index, or ponderal index. Neonates from AA + AT mothers showed lower glucose, insulin, and homeostatic model assessment insulin resistance (HOMA-IR) but higher homeostatic model assessment insulin sensitivity (HOMA-IS) and homocysteine than neonates whose mothers were TT. AA + AT neonates had higher insulin and HOMA-IR than TT. The genotype neonatal × maternal association was tested in the following four groups of neonates: TT neonates × TT mothers (nTT × mTT), TT neonates × AA + AT mothers (nTT × mAA + AT), AA + AT neonates × TT mothers (nAA + AT × mTT), and AA + AT neonates × AA + AT mothers (nAA + AT × mAA + AT). Non-significant interactions between neonatal and maternal alleles were found for any parameter tested. However, maternal alleles affected significantly glucose, insulin, HOMA-IR, and homocysteine while neonatal alleles the arylesterase activity. Most significant differences were found between nATT + AA × mTT and nATT + AA × mAA + AT. Glycemia, insulinemia, and HOMA-IR were lower, while the Mediterranean diet adherence (MDA) was higher in the mAA + AT vs. mTT whose children were AA + AT. This dietary fact seems to counterbalance the potential negative effect on glucose homeostasis of the obesogenic A allele in neonates.

Association between SLC30A8 rs13266634 Polymorphism and Type 2 Diabetes Risk: A Meta-Analysis

BACKGROUND

Accumulating but inconsistent data about the role of rs13266634 variant of SLC30A8 in type 2 diabetes have been reported, partly due to small sample sizes and non-identical ethnicity.

MATERIAL AND METHODS

We searched PubMed and Cochrane Library to identify eligible studies and extract data of baseline characteristics, genotype count, odds ratio (OR), and 95% confidence interval (CI). Both adjusted OR with 95% CI and genotype counts were employed to assess the association. Genotype data were further pooled to provide estimates under different genetic models and the most appropriate model was determined. Sensitivity and cumulative analysis were conducted to assure the strength of results.

RESULTS

Fifty-five datasets of 39 studies (including 38 of 24 with genotype count) were included. Significant associations were found in allelic contrasts using adjusted ORs and raw genotype count, respectively, overall in Asian and European populations (overall: OR=1.147/1.157, 95% CI 1.114-1.181/1.135-1.180; Asian: OR=1.186/1.165, 95% CI 1.150-1.222/1.132-1.198; European: OR=1.100/1.151, 95% CI 1.049-1.153/1.120-1.183; All p=0.00), but not in African populations (African: OR=1.255/1.111, 95% CI 0.964-1.634/0.908-1.360, p=0.091/0.305). Further analysis with genotype count under different genetic models all showed that individuals with CC genotype had 33.0% and 16.5% higher risk of type 2 diabetes than those carrying TT and CT genotypes, respectively, under the most likely codominant model. Cumulative analysis indicated gradually improved precision of estimation after studies accumulated.

CONCLUSIONS

Our results suggest that rs13266634 may be an important genetic factor of type 2 diabetes risk among Asian and European but not African populations.

TOX and CDKN2A/B Gene Polymorphisms Are Associated with Type 2 Diabetes in Han Chinese

To study associations between type 2 diabetes (T2DM) candidate genes and microvascular complications of diabetes (MVCDs), we performed case-control association studies for both T2DM and MVCDs in Han Chinese subjects. We recruited 1,939 unrelated Han Chinese T2DM patients and 918 individuals with normal blood glucose levels as nondiabetic controls. Among T2DM patients, 1116 have MVCDs, 266 have a history of T2DM of >10 years but never developed MVCDs. Eighty-two single-nucleotide polymorphisms (SNPs) in 54 candidate genes were genotyped. Discrete association studies were performed by the PLINK program for T2DM and MVCDs. Significant associations were found among candidate gene SNPs and T2DM, including rs1526167 of the TOX gene (allele A, P = 2.85 × 10⁻⁹, OR = 1.44). The SNP rs10811661 of the CDKN2A/B gene was also associated with T2DM (allele T, P = 4.09 × 10⁻⁷, OR = 1.36). When we used control patients with >10 years of T2DM history without MVCD, we found that the G allele of SNP rs1526167 of the TOX gene was associated with MVCD (nominal P = 4.33 × 10⁻⁴). In our study, significant associations were found between TOX and CDKN2A/B gene SNPs and T2DM. The TOX polymorphism might account for the higher risk of T2DM and the lower risk of MVCDs in the Han Chinese population.

Replication of KCNJ11 (p.E23K) and ABCC8 (p.S1369A) Association in Russian Diabetes Mellitus 2 Type Cohort and Meta-Analysis

The genes ABCC8 and KCNJ11 have received intense focus in type 2 diabetes mellitus (T2DM) research over the past two decades. It has been hypothesized that the p.E23K (KCNJ11) mutation in the 11p15.1 region may play an important role in the development of T2DM. In 2009, Hamming et al. found that the p.1369A (ABCC8) variant may be a causal factor in the disease; therefore, in this study we performed a meta-analysis to evaluate the association between these single nucleotide polymorphisms (SNPs), including our original data on the Siberian population (1384 T2DM and 414 controls). We found rs5219 and rs757110 were not associated with T2DM in this population, and that there was linkage disequilibrium in Siberians (D’=0.766, r²= 0.5633). In addition, the haplotype rs757110[T]-rs5219[C] (p.23K/p.S1369) was associated with T2DM (OR = 1.52, 95% CI: 1.04-2.24). We included 44 original studies published by June 2014 in a meta-analysis of the p.E23K association with T2DM. The total OR was 1.14 (95% CI: 1.11-1.17) for p.E23K for a total sample size of 137,298. For p.S1369A, a meta-analysis was conducted on a total of 10 studies with a total sample size of 14,136 and pooled OR of 1.14 [95% CI (1.08-1.19); p = 2 x 10^-6]. Our calculations identified causal genetic variation within the ABCC8/KCNJ11 region for T2DM with an OR of approximately 1.15 in Caucasians and Asians. Moreover, the OR value was not dependent on the frequency of p.E23K or p.S1369A in the populations.

Can data science inform environmental justice and community risk screening for type 2 diabetes?

Background

Having the ability to scan the entire country for potential “hotspots” with increased risk of developing chronic diseases due to various environmental, demographic, and genetic susceptibility factors may inform risk management decisions and enable better environmental public health policies.

Objectives

Develop an approach for community-level risk screening focused on identifying potential genetic susceptibility hotpots.

Methods

Our approach combines analyses of phenotype-genotype data, genetic prevalence of single nucleotide polymorphisms, and census/geographic information to estimate census tract-level population attributable risks among various ethnicities and total population for the state of California.

Results

We estimate that the rs13266634 single nucleotide polymorphism, a type 2 diabetes susceptibility genotype, has a genetic prevalence of 56.3%, 47.4% and 37.0% in Mexican Mestizo, Caucasian, and Asian populations. Looking at the top quintile for total population attributable risk, 16 California counties have greater than 25% of their population living in hotspots of genetic susceptibility for developing type 2 diabetes due to this single genotypic susceptibility factor.

Conclusions

This study identified counties in California where large portions of the population may bear additional type 2 diabetes risk due to increased genetic prevalence of a susceptibility genotype. This type of screening can easily be extended to include information on environmental contaminants of interest and other related diseases, and potentially enables the rapid identification of potential environmental justice communities. Other potential uses of this approach include problem formulation in support of risk assessments, land use planning, and prioritization of site cleanup and remediation actions.