👤 André Scherag

Acute respiratory distress syndrome (ARDS) is a severe inflammatory process of the lung, often due to sepsis, and poses significant mortality burden in intensive care units. Here we conducted a genome-wide association study (GWAS) of ARDS to identify genetic risk loci that can help guide the development of new therapeutic options. We performed a case-control GWAS in 716 cases with ARDS, mainly associated with severe infections, and 4399 at-risk controls from three independent studies. Results were meta-analysed across the three studies, with significance set at p < 5 × 10 We identified a variant near HMGCR that showed genome-wide significant association with ARDS and had been previously linked to cholesterol metabolism. This locus was associated with ANKDD1B expression in artery. The rare exonic variant analysis showed associations between HMGCR and ARDS at nominal level (p < 0.05). While no nominal significance was achieved in the two additional validation cohorts, this variant exhibited a consistent direction of effects across all 5 studies. A common variant near HMGCR was associated with ARDS risk, suggesting a link between cholesterol metabolism and ARDS risk. Validation in independent studies is needed. Wellcome Trust, National Institute for Health Research Leicester Biomedical Research Centre, National Heart, Lung, and Blood Institute, ATS Research Program, Gobierno de Canarias, Fundación Canaria Instituto de Investigación Sanitaria de Canarias, Instituto Tecnológico y de Energías Renovables, Cabildo Insular de Tenerife, Instituto de Salud Carlos III, Agencia Estatal de Investigación, German Ministry of Education and Research, Thuringian Ministry of Education, Science and Culture, the Thuringian Foundation for Technology, Innovation, and Research, German Sepsis Society. Show less

Patients with anorexia nervosa (AN) are ideally suited to identify differentially methylated genes in response to starvation. We examined high-throughput DNA methylation derived from whole blood of 47 females with AN, 47 lean females without AN and 100 population-based females to compare AN with both controls. To account for different cell type compositions, we applied two reference-free methods (FastLMM-EWASher, RefFreeEWAS) and searched for consensus CpG sites identified by both methods. We used a validation sample of five monozygotic AN-discordant twin pairs. Fifty-one consensus sites were identified in AN vs. lean and 81 in AN vs. population-based comparisons. These sites have not been reported in AN methylation analyses, but for the latter comparison 54/81 sites showed directionally consistent differential methylation effects in the AN-discordant twins. For a single nucleotide polymorphism rs923768 in CSGALNACT1 a nearby site was nominally associated with AN. At the gene level, we confirmed hypermethylated sites at TNXB. We found support for a locus at NR1H3 in the AN vs. lean control comparison, but the methylation direction was opposite to the one previously reported. We confirm genes like TNXB previously described to comprise differentially methylated sites, and highlight further sites that might be specifically involved in AN starvation processes. Show less

Large-scale genome-wide association studies have identified multiple genetic variants that are associated with elevated body mass index (BMI) or the risk of obesity in Caucasian or Asian populations. We examined whether these variants are individually associated with obesity in Chinese children, and also assessed their cumulative effects and predictive value for obesity risk in Chinese children. We genotyped 40 single nucleotide polymorphisms (SNPs) and conducted association analyses for 32/40 SNPs with an estimated minor allele frequency >1% in 2 030 unrelated Chinese children, including 607 normal-weight, 718 overweight, and 705 obese individuals from two cross-sectional study groups. Logistic regression and linear regression under the additive model were used to examine associations, and the area under the receiver operating characteristic curve (AUCROC) was reported as prediction summary. We identified obesity association for 6 SNPs near SEC16B, RBJ, CDKAL1, TFAP2B, MAP2K5 and FTO (odds ratios (ORs) ranged from 1.19 to 1.41, nominal two-sided P-values < 0.05). Association (Bonferroni corrected) of rs543874 near SEC16B and rs2241423 near MAP2K5 had presumably stronger effects on obesity in Chinese children than in Caucasian populations. Their risk alleles were also associated with BMI standard deviation score (BMI-SDS) variability. We demonstrated the cumulative effects of the 32 SNPs on obesity risk (per risk allele: OR = 1.06, 95 % CI: 1.03-1.11, P = 4.84 × 10(-4)) and BMI-SDS (β = 0.04, 95% CI: 0.02-0.06, P = 3.69 × 10(-7)). The difference in AUCROC for a model with covariates (age, age square, sex and study group) and the model including covariates and all 32 SNPs was 2.8% (P = 0.0002). While six SNPs were individually associated with obesity in Chinese children, the 32 common variants identified by recent GWA studies had cumulative effects and resulted in a limited increase in the AUCROC predictive value for childhood obesity. Show less

Deviations from normal body weight are observed prior to and after the onset of Alzheimer's disease (AD). Midlife obesity confers increased AD risk in later life, whereas late-life obesity is associated with decreased AD risk. The role of underweight and weight loss for AD risk is controversial. Based on the hypothesis of shared genetic variants for both obesity and AD, we analyzed the variants identified for AD or obesity from genome-wide association meta-analyses of the GERAD (AD, cases = 6,688, controls = 13,685) and GIANT (body mass index [BMI] as measure of obesity, n = 123,865) consortia. Our cross-disorder analysis of genome-wide significant 39 obesity SNPs and 23 AD SNPs in these two large data sets revealed that: (1) The AD SNP rs10838725 (pAD  = 1.1 × 10(-08)) at the locus CELF1 is also genome-wide significant for obesity (pBMI  = 7.35 × 10(-09) ). (2) Four additional AD risk SNPs were nominally associated with obesity (rs17125944 at FERMT2, pBMI  = 4.03 × 10(-05), pBMI corr  = 2.50 × 10(-03) ; rs3851179 at PICALM; pBMI  = 0.002, rs2075650 at TOMM40/APOE, pBMI  = 0.024, rs3865444 at CD33, pBMI  = 0.024). (3) SNPs at two of the obesity risk loci (rs4836133 downstream of ZNF608; pAD  = 0.002 and at rs713586 downstream of RBJ/DNAJC27; pAD  = 0.018) were nominally associated with AD risk. Additionally, among the SNPs used for confirmation in both studies the AD risk allele of rs1858973, with an AD association just below genome-wide significance (pAD  = 7.20 × 10(-07)), was also associated with obesity (SNP at IQCK/GPRC5B; pBMI  = 5.21 × 10(-06) ; pcorr  = 3.24 × 10(-04)). Our first GWAS based cross-disorder analysis for AD and obesity suggests that rs10838725 at the locus CELF1 might be relevant for both disorders. Show less

Children with attention-deficit/hyperactivity disorder (ADHD) have a higher rate of obesity than children without ADHD. Obesity risk alleles may overlap with those relevant for ADHD. We examined whether risk alleles for an increased body mass index (BMI) are associated with ADHD and related quantitative traits (inattention and hyperactivity/impulsivity). We screened 32 obesity risk alleles of single nucleotide polymorphisms (SNPs) in a genome-wide association study (GWAS) for ADHD based on 495 patients and 1,300 population-based controls and performed in silico analyses of the SNPs in an ADHD meta-analysis comprising 2,064 trios, 896 independent cases, and 2,455 controls. In the German sample rs206936 in the NUDT3 gene (nudix; nucleoside diphosphate linked moiety X-type motif 3) was associated with ADHD risk (OR: 1.39; P = 3.4 × 10(-4) ; Pcorr  = 0.01). In the meta-analysis data we found rs6497416 in the intronic region of the GPRC5B gene (G protein-coupled receptor, family C, group 5, member B; P = 7.2 × 10(-4) ; Pcorr  = 0.02) as a risk allele for ADHD. GPRC5B belongs to the metabotropic glutamate receptor family, which has been implicated in the etiology of ADHD. In the German sample rs206936 (NUDT3) and rs10938397 in the glucosamine-6-phosphate deaminase 2 gene (GNPDA2) were associated with inattention, whereas markers in the mitogen-activated protein kinase 5 gene (MAP2K5) and in the cell adhesion molecule 2 gene (CADM2) were associated with hyperactivity. In the meta-analysis data, MAP2K5 was associated with inattention, GPRC5B with hyperactivity/impulsivity and inattention and CADM2 with hyperactivity/impulsivity. Our results justify further research on the elucidation of the common genetic background of ADHD and obesity. Show less

Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation. Show less

In the past 20 years, obesity has become a major health problem due to associated diseases like type 2 diabetes mellitus. The gastric inhibitory polypeptide receptor (GIPR) modulates body weight and glucose homeostasis and, therefore, represents an interesting candidate gene for obesity and the comorbidity impaired glucose homeostasis. Recently, a GIPR variation was found to be associated with impaired insulin response in humans. In this study, we screened the GIPR gene for mutations and examined the association between three single-nucleotide polymorphisms (SNPs; rs8111428, rs2302382, rs1800437) and childhood obesity, as well as impaired glucose homeostasis. The coding region of the GIPR was screened for mutations by direct sequencing. We genotyped three known SNPs in 2280 healthy normal weight (1696) and obese (584) children and adolescents. Genotyping was performed using the SNaPshot protocol, the iplex, and matrix-assisted laser desorption ionization time-of-flight spectrometry technique. Obesity was defined by a body mass index SDS above 2; homeostatic model assessment was calculated. No evidence for an association was found between the SNPs and the obesity phenotype. Significant association was found between the minor allele C of the SNP rs1800437 and elevated homeostasis model of insulin resistance values (P=0.001). No further sequence variations in the GIPR were found to be associated with childhood obesity. Variations of the GIPR sequence are not associated with childhood obesity. This study points to a potential role for rs1800437 in glucose homeostasis. Further studies are necessary to confirm these results. Show less

Gastric inhibitory polypeptide (GIP) is postulated to be involved in type 2 diabetes mellitus and obesity. It exerts its function through its receptor, GIPR. We genotyped three GIPR SNPs (rs8111428, rs2302382 and rs1800437) in German families with at least one obese index patient, two case-control studies and two cross-sectional population-based studies. Genotyping was performed by MALDI-TOF, ARMS-PCR and RFLP. The family-study: 761 German families with at least one extremely obese child or adolescent (n = 1,041) and both parents (n = 1,522). Case-control study: (a) German obese children (n = 333) and (b) obese adults (n = 987) in comparison to 588 adult lean controls. The two cross-sectional population-based studies: KORA (n = 8,269) and SHIP (n = 4,310). We detected over-transmission of the A-allele of rs2302382 in the German families (pTDT-Test = 0.0089). In the combined case-control sample, we estimated an odd ratio of 1.54 (95%CI 1.09;2.19, pCA-Test = 0.014) for homozygotes of the rs2302382 A-allele compared to individuals with no A-allele. A similar trend was found in KORA where the rs2302382 A-allele led to an increase of 0.12 BMI units (p = 0.136). In SHIP, however, the A-allele of rs2302382 was estimated to contribute an average decrease of 0.27 BMI units (p-value = 0.031). Our data suggest a potential relevance of GIPR variants for obesity. However, additional studies are warranted in light of the conflicting results obtained in one of the two population-based studies. Show less