The common FTO variant rs9939609 is not associated with BMI in a longitudinal study on a cohort of Swedish men born 1920-1924

Background  

Common FTO (fat mass and obesity associated) gene variants have recently been strongly associated with body mass index and obesity in several large studies. Here we set out to examine the association of the FTO variant rs9939609 with BMI in a 32 year follow up study of men born 1920-1924. Moreover, we analyzed the effect of physical activity on the different genotypes.     

A tagging SNP in INSIG2 is associated with obesity-related phenotypes among Samoans

Background  

A genome wide association study found significant association of a sequence variant, rs7566605, in the insulin-induced gene 2 (INSIG2) with obesity. However, the association remained inconclusive in follow-up studies. We tested for association of four tagging SNPs (tagSNPs) including this variant with body mass index (BMI) and abdominal circumference (ABDCIR) in the Samoans of the Western Pacific, a population with high levels of obesity.     

The longitudinal association of common susceptibility variants for type 2 diabetes and obesity with fasting glucose level and BMI

Background  

Variation in the effects of genetic variants on physiological traits over time or with age may alter the trajectories of these traits. However, few studies have investigated this possibility for variants associated with type 2 diabetes or obesity, and these show little consensus. We aimed to characterise the possible longitudinal associations of common diabetes-susceptibility variants in the KCNJ11, PPARG, TCF7L2, IGF2BP2, CDKAL1, SLC30A8 and HHEX gene loci, with fasting glucose level; and of an obesity-associated variant in the FTO gene, with body mass index (BMI).     

Variant rs9939609 in the <Emphasis Type="Italic">FTO</Emphasis> gene is associated with body mass index among Chinese children

Background  

Fat-mass and obesity-associated (FTO) gene is a gene located in chromosome region 16q12.2. Genetic variants in FTO are associated with the obesity phenotype in European and Hispanic populations. However, this association still remains controversial in Asian population. We aimed to test the association of FTO genetic variants with obesity and obesity-related metabolic traits among children living in Beijing, China.     

<Emphasis Type="Italic">MTNR1B</Emphasis> rs10830963 is associated with fasting plasma glucose,HbA<Subscript>1C</Subscript>and impaired beta-cell function in Chinese Hans from Shanghai

Background  

Genome-wide association studies (GWAS) in White Europeans have shown that genetic variation rs10830963 in melatonin receptor 1B gene (MTNR1B) is associated with fasting glucose and type 2 diabetes, which has also been replicated in several Asian populations. As a variant in the gene involved in the regulation of circadian rhythms, the effect of the variant on sleep status remains unknown. This study aimed to investigate the effects of MTNR1B rs10830963 on fasting glucose, type 2 diabetes and sleep status in Chinese Hans.     

The role of the fat mass and obesity associated gene (<Emphasis Type="Italic">FTO</Emphasis>) in breast cancer risk

Background  

Obesity has been shown to increase breast cancer risk. FTO is a novel gene which has been identified through genome wide association studies (GWAS) to be related to obesity. Our objective was to evaluate tissue expression of FTO in breast and the role of FTO SNPs in predicting breast cancer risk.     

'Fat mass and obesity associated' gene (<Emphasis Type="Italic">FTO</Emphasis>): No significant association of variant rs9939609 with weight loss in a lifestyle intervention and lipid metabolism markers in German obese children and adolescents

Background  

We have previously identified strong association of six single nucleotide polymorphisms (SNPs) in FTO (fat mass and obesity associated gene) to early onset extreme obesity within the first genome wide association study (GWA) for this phenotype. The aim of this study was to investigate whether the obesity risk allele of one of these SNPs (rs9939609) is associated with weight loss in a lifestyle intervention program. Additionally, we tested for association of rs9939609 alleles with fasting blood parameters indicative of glucose and lipid metabolism.     

<Emphasis Type="Italic">FTO</Emphasis> variant rs9939609 is associated with body mass index and waist circumference,but not with energy intake or physical activity in European- and African-American youth

Background  

Genome-wide association studies found common variants in the fat mass and obesity-associated (FTO) gene associated with adiposity in Caucasians and Asians but the association was not confirmed in African populations. Association of FTO variants with insulin resistance and energy intake showed inconsistent results in previous studies. This study aimed to assess the influence of FTO variant rs9939609 on adiposity, insulin resistance, energy intake and physical activity in European - (EA) and African-American (AA) youth.     

<Emphasis Type="Italic">SCN5A</Emphasis>allelic expression imbalance in African-Americans heterozygous for the common variant p.Ser1103Tyr

Background  

Heterozygous and homozygous carriers of SCN5A -p.Ser1103Tyr, a common genetic variant with functional effects among African-Americans, have an increased risk of sudden death. We hypothesized that some heterozygous carriers may have unequal expression of wild-type and variant alleles and secondarily that predominance of the variant gene copy could further increase risk for sudden death in this population.     

Impact of estrogen receptor gene polymorphisms and mRNA levels on obesity and lipolysis – a cohort study

Background  

The estrogen receptors α and β (ESR1, ESR2) have been implicated in adiposity, lipid metabolism and feeding behaviour. In this report we analyse ESR1 and ESR2 gene single nucleotide polymorphisms (SNPs) for association with obesity. We also relate adipose tissue ESR1 mRNA levels and ESR1 SNPs to adipocyte lipolysis and lipogenesis phenotypes.     

Effects of genetic variations in the Adiponectin pathway genes on the risk of colorectal cancer in the Chinese population

Background

The thrifty gene hypothesis posits that, in populations that experienced periods of feast and famine, natural selection favoured individuals carrying thrifty alleles that promote the storage of fat and energy. Polynesians likely experienced long periods of cold stress and starvation during their settlement of the Pacific and today have high rates of obesity and type 2 diabetes (T2DM), possibly due to past positive selection for thrifty alleles. Alternatively, T2DM risk alleles may simply have drifted to high frequency in Polynesians. To identify thrifty alleles in Polynesians, we previously examined evidence of positive selection on T2DM-associated SNPs and identified a T2DM risk allele at unusually high frequency in Polynesians. We suggested that the risk allele of the Gly482Ser variant in the PPARGC1A gene was driven to high frequency in Polynesians by positive selection and therefore possibly represented a thrifty allele in the Pacific.

Methods

Here we examine whether PPARGC1A is a thrifty gene in Pacific populations by testing for an association between Gly482Ser genotypes and BMI in two Pacific populations (Maori and Tongans) and by evaluating the frequency of the risk allele of the Gly482Ser variant in a sample of worldwide populations.

Results

We find that the Gly482Ser variant is associated with BMI in Tongans but not in Maori. In a sample of 58 populations worldwide, we also show that the 482Ser risk allele reaches its highest frequency in the Pacific.

Conclusion

The association between Gly482Ser genotypes and BMI in Tongans together with the worldwide frequency distribution of the Gly482Ser risk allele suggests that PPARGC1A remains a candidate thrifty gene in Pacific populations.     

The <Emphasis Type="Italic">CTLA4</Emphasis> variants may interact with the <Emphasis Type="Italic">IL23R</Emphasis>- and <Emphasis Type="Italic">NOD2</Emphasis>-conferred risk in development of Crohn's disease

Background  

The CTLA4 (cytotoxic T-lymphocyte antigen 4) gene is associated with several immunopathologic diseases and because of its important immuno-regulatory role it may be considered also a plausible candidate for a genetic association with inflammatory bowel diseases. Previously published studies found no association of CTLA4 with Crohn's disease itself, but some indicated an association with its subphenotypes. The aim of this study was to assess the association in the Czech population, using a set of markers shown to associate with other diseases.     

Large-scale association analysis of <Emphasis Type="Italic">TNF</Emphasis>/<Emphasis Type="Italic">LTA</Emphasis> gene region polymorphisms in type 2 diabetes

Background  

The TNF/LTA locus has been a long-standing T2D candidate gene. Several studies have examined association of TNF/LTA SNPs with T2D but the majority have been small-scale and produced no convincing evidence of association. The purpose of this study is to examine T2D association of tag SNPs in the TNF/LTA region capturing the majority of common variation in a large-scale sample set of UK/Irish origin.     

Frequency of single nucleotide polymorphisms in NOD1 gene of ulcerative colitis patients: a case-control study in the Indian population

Background  

Epidemiological studies have provided enough evidence that genetic factors have an important role in determining susceptibility to IBD. The most significant finding in the IBD research has been identification of mutations in the gene that encodes Nod2 (nucleotide-binding oligomerization domain 2) protein in a subgroup of patients with Crohn's disease. However, a very similar gene encoding Nod1 protein still has not been well documented for its association with Ulcerative colitis patients. Detection of polymorphism in NOD1 gene using SNP analysis has been attempted in the present study. We evaluated frequency and significance of mutations present in the nucleotide-binding domain (NBD) of NOD1 gene in context to Indian population.     

Association between variations in the <Emphasis Type="Italic">TLR4</Emphasis>gene and incident type 2 diabetes is modified by the ratio of total cholesterol to HDL-cholesterol

Background  

Toll-like receptor 4 (TLR4), the signaling receptor for lipopolysaccharides, is an important member of the innate immunity system. Since several studies have suggested that type 2 diabetes might be associated with changes in the innate immune response, we sought to investigate the association between genetic variants in the TLR4 gene and incident type 2 diabetes.     

Pharmacogenetics of glucocorticoid replacement could optimize the treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

INTRODUCTION:

21-hydroxylase deficiency is an autosomal recessive disorder that causes glucocorticoid deficiency and increased androgen production. Treatment is based on glucocorticoid replacement; however, interindividual variability in the glucocorticoid dose required to achieve adequate hormonal control has been observed.

OBJECTIVE:

The present study aimed to evaluate the association between polymorphic variants involved in glucocorticoid action and/or metabolism and the mean daily glucocorticoid dose in 21-hydroxylase deficiency patients.

METHODS:

We evaluated 53 patients with classical forms of 21-hydroxylase deficiency who were receiving cortisone acetate. All patients were between four and six years of age and had normal androgen levels.

RESULTS:

The P450 oxidoreductase A503V, HSD11B1 rs12086634, and CYP3A7*1C variants were found in 19%, 11.3% and 3.8% of the patients, respectively. The mean±SD glucocorticoid dose in patients with the CYP3A7*1C and wild-type alleles was 13.9±0.8 and 19.5±3.2 mg/m²/d, respectively. We did not identify an association between the P450 oxidoreductase or HSD11B1 allelic variants and the mean glucocorticoid dose.

CONCLUSION:

Patients carrying the CYP3A7*1C variant required a significantly lower mean glucocorticoid dose. Indeed, the CYP3A7*1C allele accounted for 20% of the variability in the cortisone acetate dose. The analysis of genes involved in glucocorticoid metabolism may be useful in the optimization of treatment of 21-hydroxylase deficiency.     

Variants in <Emphasis Type="Italic">KCNQ1</Emphasis> increase type II diabetes susceptibility in South Asians: A study of 3,310 subjects from India and the US

Background  

Polymorphisms in intron 15 of potassium voltage-gated channel, KQT-like subfamily member 1 (KCNQ1) gene have been associated with type II diabetes (T2D) in Japanese genome-wide association studies (GWAS). More recently a meta-analysis of European GWAS has detected a new independent signal associated with T2D in intron 11 of the KCNQ1 gene. The purpose of this investigation is to examine the role of these variants with T2D in populations of Asian Indian descent from India and the US.     

Glucocorticoid receptor gene polymorphisms do not affect growth in fetal and early postnatal life. The Generation R Study

Background  

Glucocorticoids have an important role in early growth and development. Glucocorticoid receptor gene polymorphisms have been identified that contribute to the variability in glucocorticoid sensitivity. We examined whether these glucocorticoid receptor gene polymorphisms are associated with growth in fetal and early postnatal life.     

Role of metabolically active hormones in the insulin resistance associated with short-term glucocorticoid treatment

Background  

The mechanisms by which glucocorticoid therapy promotes obesity and insulin resistance are incompletely characterized. Modulations of the metabolically active hormones, tumour necrosis factor alpha (TNF alpha), ghrelin, leptin and adiponectin are all implicated in the development of these cardiovascular risk factors. Little is known about the effects of short-term glucocorticoid treatment on levels of these hormones.     

Evaluation of <Emphasis Type="Italic">DOK5</Emphasis> as a susceptibility gene for type 2 diabetes and obesity in North Indian population

Background  

Type 2 diabetes is a complex metabolic disorder with obesity being a major contributing factor in its development. Susceptibility loci for type 2 diabetes and obesity have been localized on different chromosomal regions by various genome-wide linkage scans. Of these chromosomal regions, 20q13 is one of the strongest linked regions for type 2 diabetes as well as obesity. On 20q13 lies DOK5 that seems to be a strong functional and positional candidate for type 2 diabetes and obesity because of its involvement in insulin signaling and immune responses. Hence, for the first time, we explored DOK5 as a potential type 2 diabetes and obesity susceptibility gene.