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Background Consanguine families display a high degree of homozygosity which increases the risk of family members suffering from autosomal recessive disorders. Thus, homozygous mutations in monogenic obesity genes may be a more frequent cause of childhood obesity in a consanguineous population. Methods We identified 23 probands from 23 Pakistani families displaying autosomal recessive obesity. We have previously excluded mutations in MC4R, LEP and LEPR in all probands. Using a chip-based, target-region capture array, 31 genes involved in monogenic forms of obesity, were screened in all probands. Results We identified 31 rare non-synonymous possibly pathogenic variants (28 missense and three nonsense) within the 31 selected genes. All variants were heterozygous, thus no homozygous pathogenic variants were found. Two of the rare heterozygous nonsense variants identified (p.R75X and p.R481X) were found in BBS9 within one proband, suggesting that obesity is caused by compound heterozygosity. Sequencing of the parents supported the compound heterozygous nature of obesity as each parent was carrying one of the variants. Subsequent clinical investigation strongly indicated that the proband had Bardet-Biedl syndrome. Conclusions Mutation screening in 31 genes among probands with severe early-onset obesity from Pakistani families did not reveal the presence of homozygous obesity causing variants. However, a compound heterozygote carrier of BBS9 mutations was identified, indicating that compound heterozygosity must not be overlooked when investigating the genetic etiology of severe childhood obesity in populations with a high degree of consanguinity. Electronic supplementary material The online version of this article (10.1186/s12881-019-0886-8) contains supplementary material, which is available to authorized users.

Context Pancreatic beta-cell glucose sensitivity is the slope of the plasma glucose-insulin secretion relationship and is a key predictor of deteriorating glucose tolerance and development of type 2 diabetes. However, there are no large-scale studies looking at the genetic determinants of beta-cell glucose sensitivity. Objective To understand the genetic determinants of pancreatic beta-cell glucose sensitivity using genome-wide meta-analysis and candidate gene studies. Design We performed a genome-wide meta-analysis for beta-cell glucose sensitivity in subjects with type 2 diabetes and nondiabetic subjects from 6 independent cohorts (n = 5706). Beta-cell glucose sensitivity was calculated from mixed meal and oral glucose tolerance tests, and its associations between known glycemia-related single nucleotide polymorphisms (SNPs) and genome-wide association study (GWAS) SNPs were estimated using linear regression models. Results Beta-cell glucose sensitivity was moderately heritable (h2 ranged from 34% to 55%) using SNP and family-based analyses. GWAS meta-analysis identified multiple correlated SNPs in the CDKAL1 gene and GIPR-QPCTL gene loci that reached genome-wide significance, with SNP rs2238691 in GIPR-QPCTL (P value = 2.64 × 10−9) and rs9368219 in the CDKAL1 (P value = 3.15 × 10−9) showing the strongest association with beta-cell glucose sensitivity. These loci surpassed genome-wide significance when the GWAS meta-analysis was repeated after exclusion of the diabetic subjects. After correction for multiple testing, glycemia-associated SNPs in or near the HHEX and IGF2B2 loci were also associated with beta-cell glucose sensitivity. Conclusion We show that, variation at the GIPR-QPCTL and CDKAL1 loci are key determinants of pancreatic beta-cell glucose sensitivity.

Aims Insulin resistance associates with development of metabolic syndrome and risk of cardiovascular disease. The link between insulin resistance and cardiovascular disease is complex and multifactorial. Confirming the genetic link between insulin resistance, type 2 diabetes, and coronary artery disease, as well as the extent of coronary artery disease, is important and may provide better risk stratification for patients at risk. We investigated whether a genetic risk score of 53 single nucleotide polymorphisms known to be associated with insulin resistance phenotypes was associated with diabetes and burden of coronary artery disease. Methods and results We genotyped patients with a coronary angiography performed in the capital region of Denmark from 2010–2014 and constructed a genetic risk score of the 53 single nucleotide polymorphisms. Logistic regression using quartiles of the genetic risk score was performed to determine associations with diabetes and coronary artery disease. Associations with the extent of coronary artery disease, defined as one-, two- or three-vessel coronary artery disease, was determined by multinomial logistic regression. We identified 4,963 patients, of which 17% had diabetes and 55% had significant coronary artery disease. Of the latter, 27%, 14% and 14% had one, two or three-vessel coronary artery disease, respectively. No significant increased risk of diabetes was identified comparing the highest genetic risk score quartile with the lowest. An increased risk of coronary artery disease was found for patients with the highest genetic risk score quartile in both unadjusted and adjusted analyses, OR 1.21 (95% CI: 1.03, 1.42, p = 0.02) and 1.25 (95% CI 1.06, 1.48, p Conclusions Among patients referred for coronary angiography, only a strong genetic predisposition to insulin resistance was associated with risk of coronary artery disease and with a greater disease burden.

The genetic background of childhood body mass index (BMI), and the extent to which the well-known associations of childhood BMI with adult diseases are explained by shared genetic factors, are largely unknown. We performed a genome-wide association study meta-analysis of BMI in 61,111 children aged between 2 and 10 years. Twenty-five independent loci reached genome-wide significance in the combined discovery and replication analyses. Two of these, located nearNEDD4LandSLC45A3, have not previously been reported in relation to either childhood or adult BMI. Positive genetic correlations of childhood BMI with birth weight and adult BMI, waist-to-hip ratio, diastolic blood pressure and type 2 diabetes were detected (R(g)ranging from 0.11 to 0.76, P-values, CP received funding from the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London. MMcC is a Wellcome Senior Investigator and an NIHR Senior Investigator. MMcC received funding from Wellcome (090532, 106130, 098381, 203141, 212259), NIDDK (U01DK105535), and NIHR (NF-SI-0617-10090). TGMV was supported by ZonMW (TOP 40-00812-9811010). DLC was supported by the American Diabetes Association Grant 1-17-PDF-077. SFAG is supported by the Daniel B. Burke Chair for Diabetes Research and NIH Grant R01 HD058886. NVT is funded by a pre-doctoral grant from the Agencia de Gestio d'Ajuts Universitaris i de Recerca (2017 FI_B 00636), Generalitat de Catalunya -Fons Social Europeu. BK received personal funding from the European Research Council Advanced Grant META-GROWTH (ERC-2012-AdG -no. 322605). BF was supported by an Oak Foundation Fellowship. RMF and RNB are supported by Sir Henry Dale Fellowship (Wellcome Trust and Royal Society grant: WT104150). ATH is supported by a Wellcome Trust Senior Investigator award (grant number 098395/Z/12/Z). DM is supported by a Canada Research Chair. DLC was supported by the American Diabetes Association Grant 1-17-PDF077. JTL was supported by the Finnish Cultural Foundation. DIB received a KNAW Academy Professor Award (PAH/6635). MH received PhD scholarship funding from TARGET (http://target.ku.dk), The Danish Diabetes Academy (http://danishdiabetesacademy.dk) and the Copenhagen Graduate School of Health and Medical Sciences. VWVJ received funding from the Netherlands Organization for Health Research and Development (VIDI 016.136.361) and the European Research Council (ERC-2014-CoG-648916). ISF was supported by the European Research Council, Wellcome Trust (098497/Z/12/Z), Medical Research Council (MRC_MC_UU_12012/5), the NIHR Cambridge Biomedical Research Centre, the Botnar Foundation, the Bernard Wolfe Health Neuroscience Endowment and the European Community's Seventh Framework Programme (FP7/2007-2013) project Beta-JUDO n degrees 279153. IB acknowledges funding from Wellcome (WT206194). ES works in a unit that receives funding from the University of Bristol and the UK Medical Research Council (MC_UU_00011/1, MC_UU_00011/3). GDS works in the Medical Research Council Integrative Epidemiology Unit at the University of Bristol, which is supported by the Medical Research Council (MC_UU_00011/1). KC received funds from the French National Agency of Research, F-CRIN/FORCE. All funding for the studies that provided the underlying data for this manuscript can be found in S1 Text. The funders had no role in study design, data collection and analysis, data interpretation, decision to publish, or preparation of the manuscript.

Summary Individuals with obesity due to pathogenic heterozygous melanocortin 4 receptor (MC4R) mutations can be treated efficiently with the glucagon-like peptide-1 receptor agonist (GLP-1 RA) liraglutide. Here, we report the effect of 16 weeks of liraglutide 3 mg/day treatment in a woman with morbid obesity and type 2 diabetes (T2D) due to homozygous pathogenic MC4R mutation. The body weight loss was 9.7 kg, similar to weight loss in heterozygous MC4R mutation carriers and common obesity. In addition, the treatment led to clinically relevant decreases in fasting glucose, triglycerides, systolic blood pressure, and normalization of glucose tolerance. We conclude that liraglutide reduces body weight and blood glucose levels in hetero- and homozygous MC4R mutation carriers. This serves as proof-of-concept that MC4Rs are not required for the body weight and glucose lowering effects of GLP-1 RAs and that liraglutide may be used as part of the treatment of obesity and T2D due to MC4R mutations., Graphical Abstract, Highlights Liraglutide induces weight loss in a woman homozygous for pathogenic MC4R mutation Glucose tolerance normalized and fasting glucose and triglyceride levels reduced MC4R is not required for GLP-1 RA-mediated weight loss Liraglutide is an effective treatment for the most common form of monogenic obesity, In this case report, Iepsen et al. show that the GLP-1 RA liraglutide induces a weight loss of 10 kg and normalization of glucose tolerance in a woman homozygous for pathogenic MC4R mutation. Thus, the appetite-reducing effects of liraglutide are preserved in MC4R causal obesity and independent of the MC4R pathway.

Overweight in children is strongly associated with parental body mass index (BMI) and overweight. We assessed parental transmitted and non-transmitted genetic contributions to overweight in children from the Danish National Birth Cohort by constructing genetic risk scores (GRSs) from 941 common genetic variants associated with adult BMI and estimating associations of transmitted maternal/paternal and non-transmitted maternal GRS with child overweight. Maternal and paternal BMI (standard deviation (SD) units) had a strong association with childhood overweight [Odds ratio (OR): 2.01 (95% confidence interval (CI) 1.74; 2.34) and 1.64 (95% CI 1.43; 1.89)]. Maternal and paternal transmitted GRSs (SD-units) increased odds for child overweight equally [OR: 1.30 (95% CI 1.16; 1.46) and 1.30 (95% CI 1.16; 1.47)]. However, both the parental phenotypic and the GRS associations may depend on maternal BMI, being weaker among mothers with overweight. Maternal non-transmitted GRS was not associated with child overweight [OR 0.98 (95% CI 0.88; 1.10)] suggesting no specific influence of maternal adiposity as such. In conclusion, parental transmitted GRSs, based on adult BMI, contribute to child overweight, but in overweight mothers other genetic and environmental factors may play a greater role.

Objective This study aimed to investigate the effect of a genetic risk score (GRS) comprising 15 single-nucleotide polymorphisms, previously shown to associate with childhood BMI, on the baseline cardiometabolic traits and the response to a lifestyle intervention in Danish children and adolescents. Methods Children and adolescents with overweight or obesity (n = 920) and a population-based control sample (n = 698) were recruited. Anthropometric and biochemical measures were obtained at baseline and in a subgroup of children and adolescents with overweight or obesity again after 6 to 24 months of lifestyle intervention (n = 754). The effects of the GRS were examined by multiple linear regressions using additive genetic models. Results At baseline, the GRS associated with BMI standard deviation score (SDS) both in children and adolescents with overweight or obesity (β = 0.033 [SE = 0.01]; P = 0.001) and in the population-based sample (β = 0.065 [SE = 0.02]; P = 0.001). No associations were observed for cardiometabolic traits. The GRS did not influence changes in BMI SDS or cardiometabolic traits following lifestyle intervention. Conclusions A GRS for childhood BMI was associated with BMI SDS but not with other cardiometabolic traits in Danish children and adolescents. The GRS did not influence treatment response following lifestyle intervention.

Aims: To use the rs1229984 variant associated with alcohol consumption as an instrument for alcohol consumption to test the causality of the association of alcohol consumption with hay fever, asthma, allergic sensitization and serum total immunoglobulin (Ig)E. Design: Observational and Mendelian randomization analyses using genetic variants as unbiased markers of exposure to estimate causal effects, subject to certain assumptions. Setting: Europe. Participants: We included a total of 466 434 people aged 15–82 years from 17 population-based studies conducted from 1997 to 2015. Measurements: The rs1229984 (ADH1B) was genotyped; alcohol consumption, hay fever and asthma were self-reported. Specific and total IgE were measured from serum samples. Findings: Observational analyses showed that ever-drinking versus non-drinking, but not amount of alcohol intake, was positively associated with hay fever and inversely associated with asthma but not with allergic sensitization or serum total immunoglobulin (Ig)E. However, Mendelian randomization analyses did not suggest that the observational associations are causal. The causal odds ratio (OR) per genetically assessed unit of alcohol/week was an OR = 0.907 [95% confidence interval (CI) = 0.806, 1.019; P = 0.101] for hay fever, an OR = 0.897 (95% CI = 0.790, 1.019; P = 0.095) for asthma, an OR = 0.971 (95% CI = 0.804, 1.174; P = 0.763) for allergic sensitization and a 4.7% change (95% CI = –5.5%, 14.9%; P = 0.366) for total IgE. Conclusions: In observational analyses, ever-drinking versus not drinking was positively associated with hay fever and negatively associated with asthma. However, the Mendelian randomization results were not consistent with these associations being causal.

Increased sedentariness has been linked to the growing prevalence of obesity in children, but some longitudinal studies suggest that sedentariness may be a consequence rather than a cause of increased adiposity. We used Mendelian randomization to examine the causal relations between body mass index (BMI) and objectively assessed sedentary time and physical activity in 3–8 year-old children from one Finnish and two Danish cohorts [NTOTAL=679]. A genetic risk score (GRS) comprised of 15 independent genetic variants associated with childhood BMI was used as the instrumental variable to test causal effects of BMI on sedentary time, total physical activity, and moderate-to-vigorous physical activity (MVPA). In fixed effects meta-analyses, the GRS was associated with 0.05 SD/allele increase in sedentary time (P=0.019), but there was no significant association with total physical activity (beta=0.011 SD/allele, P=0.58) or MVPA (beta=0.001 SD/allele, P=0.96), adjusting for age, sex, monitor wear-time and first three genome-wide principal components. In two-stage least squares regression analyses, each genetically instrumented one unit increase in BMI z-score increased sedentary time by 0.47 SD (P=0.072). Childhood BMI may have a causal influence on sedentary time but not on total physical activity or MVPA in young children. Our results provide important insights into the regulation of movement behaviour in childhood., final draft, peerReviewed