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1.
Am J Clin Nutr ; 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31504107

RESUMO

BACKGROUND: Mendelian randomization studies in adults suggest that abdominal adiposity is causally associated with increased risk of type 2 diabetes and coronary artery disease in adults, but its causal effect on cardiometabolic risk in children remains unclear. OBJECTIVE: We aimed to study the causal relation of abdominal adiposity with cardiometabolic risk factors in children by applying Mendelian randomization. METHODS: We constructed a genetic risk score (GRS) using variants previously associated with waist-to-hip ratio adjusted for BMI (WHRadjBMI) and examined its associations with cardiometabolic factors by linear regression and Mendelian randomization in a meta-analysis of 6 cohorts, including 9895 European children and adolescents aged 3-17 y. RESULTS: WHRadjBMI GRS was associated with higher WHRadjBMI (ß = 0.021 SD/allele; 95% CI: 0.016, 0.026 SD/allele; P = 3 × 10-15) and with unfavorable concentrations of blood lipids (higher LDL cholesterol: ß = 0.006 SD/allele; 95% CI: 0.001, 0.011 SD/allele; P = 0.025; lower HDL cholesterol: ß = -0.007 SD/allele; 95% CI: -0.012, -0.002 SD/allele; P = 0.009; higher triglycerides: ß = 0.007 SD/allele; 95% CI: 0.002, 0.012 SD/allele; P = 0.006). No differences were detected between prepubertal and pubertal/postpubertal children. The WHRadjBMI GRS had a stronger association with fasting insulin in children and adolescents with overweight/obesity (ß = 0.016 SD/allele; 95% CI: 0.001, 0.032 SD/allele; P = 0.037) than in those with normal weight (ß = -0.002 SD/allele; 95% CI: -0.010, 0.006 SD/allele; P = 0.605) (P for difference = 0.034). In a 2-stage least-squares regression analysis, each genetically instrumented 1-SD increase in WHRadjBMI increased circulating triglycerides by 0.17 mmol/L (0.35 SD, P = 0.040), suggesting that the relation between abdominal adiposity and circulating triglycerides may be causal. CONCLUSIONS: Abdominal adiposity may have a causal, unfavorable effect on plasma triglycerides and potentially other cardiometabolic risk factors starting in childhood. The results highlight the importance of early weight management through healthy dietary habits and physically active lifestyle among children with a tendency for abdominal adiposity.

2.
BMC Med Genet ; 20(1): 152, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488071

RESUMO

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.

3.
J Bone Miner Metab ; 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31471646

RESUMO

Pathogenic mutations in the melanocortin-4 receptor (MC4R) are associated with obesity, increased linear growth, and higher bone mass in children, and rodent studies have indicated an effect of the MC4R on bone turnover. Furthermore, GLP-1 receptor agonists (GLP-1 RAs) may influence bone metabolism. However, these associations have not been assessed in adults with pathogenic MC4R mutations. Thus, we wished to assess the impact of the MC4R on bone mass and metabolism. Secondly, we wished to investigate the impact of the GLP-1 RA liraglutide on bone mass in adults with pathogenic MC4R mutations. 17 patients with obesity-causing MC4R mutations (BMI: 35.5 ± 7.6) and 35 matched control participants with common obesity (BMI: 34.3 ± 7.1) underwent a DEXA scan for assessment of bone mineral density (BMD), bone mineral apparent density [BMAD = (BMD/√(bone area)], and bone turnover markers (BTMs). Individuals with a BMI above 28 (14 MC4R mutation carriers and 28 matched control participants) underwent 16 weeks treatment with liraglutide 3.0 mg. The MC4R group had higher BMD [mean difference: 0.065 g/m2 (- 0.008 to 0.138), p = 0.03], but BMAD and BTMS were not different compared to the control group. In response to liraglutide, BMAD increased in the control group, compared to no change in the MC4R group [mean group difference: 0.0007 (0.0001-0.001), p = 0.04]. In conclusion, BMD is increased in MC4R causal obesity compared to common obesity, but when corrected for body size (BMAD), bone mass was not increased, and no evidence of an influence of the MC4R on bone metabolism in adults was found. Liraglutide treatment did not change bone metabolism in MC4R causal obesity, but increased bone mass as measured by BMAD in common obesity.

4.
Hum Mol Genet ; 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31504550

RESUMO

Although hundreds of GWAS-implicated loci have been reported for adult obesity-related traits, less is known about the genetics specific for early-onset obesity, and with only a few studies conducted in non-European populations to date. Searching for additional genetic variants associated with childhood obesity, we performed a trans-ancestral meta-analysis of thirty studies consisting of up to 13,005 cases (≥95th percentile of BMI achieved 2-18 years old) and 15,599 controls (consistently <50th percentile of BMI) of European, African, North/South American and East Asian ancestry. Suggestive loci were taken forward for replication in a sample of 1,888 cases and 4,689 controls from seven cohorts of European and North/South American ancestry. In addition to observing eighteen previously implicated BMI or obesity loci, for both early and late onset, we uncovered one completely novel locus in this trans-ancestral analysis (nearest gene: METTL15). The variant was nominally associated in only the European subgroup analysis but had a consistent direction of effect in other ethnicities. We then utilized trans-ancestral Bayesian analysis to narrow down the location of the probable causal variant at each genome-wide significant signal. Of all the fine-mapped loci, we were able to narrow down the causative variant at four known loci to fewer than ten SNPs (FAIM2, GNPDA2, MC4R and SEC16B loci). In conclusion, an ethnically diverse setting has enabled us to both identify an additional pediatric obesity locus and further fine-map existing loci.

5.
PLoS One ; 14(8): e0220805, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31415576

RESUMO

BACKGROUND: Based on the association of common GLIS3 variants with various forms of diabetes and the biological role of GLIS3 in beta-cells, we sequenced GLIS3 in non-diabetic and diabetic Danes to investigate the effect of rare missense variants on glucose metabolism. METHODS: We sequenced 53 patients with maturity-onset diabetes of the young (MODY), 5,726 non-diabetic participants, 2,930 patients with newly diagnosed type 2 diabetes and 206 patients with glutamic acid decarboxylase antibody (GADA) -positive diabetes. RESULTS: In total we identified 86 rare (minor allele frequency < 0.1%) missense variants. None was considered causal for the presence of MODY. Among patients with type 2 diabetes, we observed a higher prevalence of rare GLIS3 missense variants (2.5%) compared to non-diabetic individuals (1.8%) (odds ratio of 1.37 (interquartile range:1.01-1.88, p = 0.04)). A significantly increased HbA1c was found among patients with type 2 diabetes and with GADA-positive diabetes carrying rare GLIS3 variants compared to non-carriers of rare GLIS3 variants with diabetes (p = 0.02 and p = 0.004, respectively). One variant (p.I28V) was found to have a minor allele frequency of only 0.03% among patients with type 2 diabetes compared to 0.2% among non-diabetic individuals suggesting a protective function (odds ratio of 0.20 (interquartile range: 0.005-1.4, p = 0.1)), an effect which was supported by publically available data. This variant was also associated with a lower level of fasting plasma glucose among non-diabetic individuals (p = 0.046). CONCLUSION: Rare missense variants in GLIS3 associates nominally with increased level of HbA1c and increased risk of developing type 2 diabetes. In contrast, the rare p.I28V variant associate with reduced level of fasting plasma glucose and may be protective against type 2 diabetes.

6.
Int J Obes (Lond) ; 43(10): 2007-2016, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31332278

RESUMO

BACKGROUND: Most obese children show cardiometabolic impairments, such as insulin resistance, dyslipidemia, and hypertension. Yet some obese children retain a normal cardiometabolic profile. The mechanisms underlying this variability remain largely unknown. We examined whether genetic loci associated with increased insulin sensitivity and relatively higher fat storage on the hip than on the waist in adults are associated with a normal cardiometabolic profile despite higher adiposity in children. METHODS: We constructed a genetic score using variants previously linked to increased insulin sensitivity and/or decreased waist-hip ratio adjusted for body mass index (BMI), and examined the associations of this genetic score with adiposity and cardiometabolic impairments in a meta-analysis of six cohorts, including 7391 European children aged 3-18 years. RESULTS: The genetic score was significantly associated with increased degree of obesity (higher BMI-SDS beta = 0.009 SD/allele, SE = 0.003, P = 0.003; higher body fat mass beta = 0.009, SE = 0.004, P = 0.031), yet improved body fat distribution (lower WHRadjBMI beta = -0.014 SD/allele, SE = 0.006, P = 0.016), and favorable concentrations of blood lipids (higher HDL cholesterol: beta = 0.010 SD/allele, SE = 0.003, P = 0.002; lower triglycerides: beta = -0.011 SD/allele, SE = 0.003, P = 0.001) adjusted for age, sex, and puberty. No differences were detected between prepubertal and pubertal/postpubertal children. The genetic score predicted a normal cardiometabolic profile, defined by the presence of normal glucose and lipid concentrations, among obese children (OR = 1.07 CI 95% 1.01-1.13, P = 0.012, n = 536). CONCLUSIONS: Genetic predisposition to higher body fat yet lower cardiometabolic risk exerts its influence before puberty.

7.
Obes Surg ; 29(8): 2554-2561, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31001758

RESUMO

BACKGROUND: The weight loss after bariatric surgery shows considerable individual variation. Twin studies of response to dietary interventions and studies of bariatric surgery patients suggest that genetic differences may play a role. This study aimed to examine the effect of three genetic risk scores on the inter-individual variation in excess body mass index loss (EBMIL) after Roux-en-Y gastric bypass. Furthermore, we searched among known adiposity-related single nucleotide polymorphisms (SNPs) for genetic determinants of the inter-individual variation in EBMIL. METHODS: Patients with morbid obesity underwent Roux-en-Y gastric bypass and were genotyped (n = 577). Two genetic risk scores for weight loss after bariatric surgery and a genetic risk score for body mass index were calculated. Associations between the genetic risk scores and EBMIL were evaluated. Lasso regression was performed on 126 SNPs known to be associated with adiposity. RESULTS: The average EBMIL was 76.9% (range 21.7-149.2%). EBMIL was 81.1% (SD 20.6) and 73.9% (SD 21.7) in the high and low tertile groups of a genetic risk score for weight loss. Patients with a low genetic risk score for body mass index (in the lowest 5% percentile) had an EBMIL of 68.8% (SD 20.6, p = 0.018). Thirteen adiposity-related SNPs were identified to associate with EBMIL through lasso regression. DISCUSSION: A genetic risk score was associated with EBMIL after bariatric surgery, but may not yet be applicable to clinical practice. Patients genetically predisposed to low body mass index had lower weight loss after bariatric surgery.

8.
PLoS One ; 14(1): e0210114, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30629617

RESUMO

BACKGROUND: PPP1R3B has been suggested as a candidate gene for monogenic forms of diabetes as well as type 2 diabetes (T2D) due to its association with glycaemic trait and its biological role in glycogen synthesis. OBJECTIVES: To study if rare missense variants in PPP1R3B increase the risk of maturity onset diabetes of the young (MODY), T2D or affect measures of glucose metabolism. METHOD: Targeted resequencing of PPP1R3B was performed in 8,710 samples; MODY patients with unknown etiology (n = 54), newly diagnosed patients with T2D (n = 2,930) and population-based control individuals (n = 5,726, of whom n = 4,569 had normal glucose tolerance). All population-based sampled individuals were examined using an oral glucose tolerance test. RESULTS: Among n = 396 carriers, we identified twenty-three PPP1R3B missense mutations, none of which segregated with MODY. The burden of likely deleterious PPP1R3B variants was significantly increased with a total of 17 carriers among patients with T2D (0.58% (95% CI: 0.36-0.93)) compared to 18 carriers among non-diabetic individuals (0.31% (95% CI: 0.20-0.49)), resulting in an increased risk of T2D (OR (95% CI) = 2.57 (1.14-5.79), p = 0.02 (age and sex adjusted)). Furthermore, carriers with diabetes had less abdominal fat and a higher serum concentration of LDL-cholesterol compared to patients with T2D without rare missense PPP1R3B variants. In addition, non-diabetic carriers had a higher birth weight compared to non-carriers. CONCLUSION: Rare missense PPP1R3B variants may predispose to T2D.


Assuntos
Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença , Proteína Fosfatase 1/genética , Idoso , Glicemia/genética , Dinamarca , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Feminino , Teste de Tolerância a Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto
9.
BMC Med Genet ; 19(1): 207, 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30514227

RESUMO

BACKGROUND: The genetics of fetal insulin release and/or action have been suggested to affect fetal growth, adult insulin resistance and adult body composition. The genetic correlation between body composition at birth versus glycaemic regulation and body composition in adulthood have, however, not been well studied. We therefore aimed to investigate these genetic correlations in a family-based cohort. METHODS: A Danish family cohort of 434 individuals underwent an oral glucose tolerance test with subsequent calculation of surrogate measures of serum insulin response and insulin sensitivity. Measures of fetal growth were retrieved from midwife journals. Heritability and genetic correlations were estimated using a variance component model. RESULTS: A high heritability of 0.80 was found for birth weight, whereas ponderal index had a heritability of 0.46. Adult insulin sensitivity measured as Matsuda index was genetically correlated with both birth weight and ponderal index (ρG = 0.36 (95% CI: 0.03; 0.69) and ρG = 0.52 (95% CI, 0.15; 0.89), respectively). Only birth weight showed a significant genetic correlation with adult weight (ρG = 0.38 (95% CI: 0.09; 0.67)) whereas only ponderal index was genetically inversely correlated with fasting insulin (ρG = - 0.47 (95% CI: - 0.86; - 0.08) and area under the curve for insulin release during the oral glucose tolerance test (ρG = - 0.66 (95% CI: - 1.13; - 0.19)). Individual as well as combined adjustment for 45 selected birth weight, obesity and type 2 diabetes susceptibility gene variants did not affect the correlations. CONCLUSIONS: The genetics of both birth weight and ponderal index appear to be under the same genetic influence as adult insulin resistance. Furthermore, ponderal index and adult insulin release seem to be partly shared, as well as the genetics of birth weight and adult weight. Word count abstract: 281.

10.
Obesity (Silver Spring) ; 26(12): 1915-1922, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30460774

RESUMO

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 (ß = 0.033 [SE = 0.01]; P = 0.001) and in the population-based sample (ß = 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.

11.
BMC Med Genet ; 19(1): 199, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30442103

RESUMO

BACKGROUND: Mutations in the genes encoding leptin (LEP), the leptin receptor (LEPR), and the melanocortin 4 receptor (MC4R) are known to cause severe early-onset childhood obesity. The aim of the current study was to examine the prevalence of damaging LEP, LEPR, and MC4R mutations in Pakistani families having a recessive heritance of early-onset obesity. METHODS: Using targeted resequencing, the presence of rare mutations in LEP, LEPR, and MC4R, was investigated in individuals from 25 families suspected of having autosomal recessive early-onset obesity. Segregation patterns of variants were assessed based on chip-based genotyping. RESULTS: Homozygous LEPR variants were identified in two probands. One carried a deletion (c.3260AG) resulting in the frameshift mutation p.Ser1090Trpfs*6, and the second carried a substitution (c.2675C > G) resulting in the missense mutation p.Pro892Arg. Both mutations were located within regions of homozygosity shared only among affected individuals. Both probands displayed early-onset obesity, hyperphagia and diabetes. No mutations were found in LEP and MC4R. CONCLUSIONS: The current study highlights the implication of LEPR mutations in cases of severe early-onset obesity in consanguineous Pakistani families. Through targeted resequencing, we identified novel damaging mutations, and our approach may therefore be utilized in clinical testing or diagnosis of known forms of monogenic obesity with the aim of optimizing obesity treatment.

12.
Cell Metab ; 28(1): 23-32.e3, 2018 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-29861388

RESUMO

Pathogenic mutations in the appetite-regulating melanocortin-4 receptor (MC4R) represent the most common cause of monogenic obesity with limited treatment options. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) cause weight loss by reducing appetite. We assessed the effect of the GLP-1 RA liraglutide 3.0 mg for 16 weeks in 14 obese individuals with pathogenic MC4R mutations (BMI 37.5 ± 6.8) and 28 matched control participants without MC4R mutation (BMI 36.8 ± 4.8). Liraglutide decreased body weight by 6.8 kg ± 1.8 kg in individuals with pathogenic MC4R mutations and by 6.1 kg ± 1.2 kg in control participants. Total body fat, waist circumference, and fasting and postprandial glucose concentrations similarly decreased in both groups. Thus, liraglutide induced an equal, clinically significant weight loss of 6% in both groups, indicating that the appetite-reducing effect of liraglutide is preserved in MC4R causal obesity and that liraglutide acts independently of the MC4R pathway. Thus, liraglutide could be an effective treatment of the most common form of monogenic obesity.

13.
Diabetologia ; 61(8): 1769-1779, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29855666

RESUMO

AIMS/HYPOTHESIS: A genetic risk score (GRS) consisting of 53 insulin resistance variants (GRS53) was recently demonstrated to associate with insulin resistance in adults. We speculated that the GRS53 might already associate with insulin resistance during childhood, and we therefore aimed to investigate this in populations of Danish children and adolescents. Furthermore, we aimed to address whether the GRS associates with components of the metabolic syndrome and altered body composition in children and adolescents. METHODS: We examined a total of 689 children and adolescents who were overweight or obese and 675 children and adolescents from a population-based study. Anthropometric data, dual-energy x-ray absorptiometry scans, BP, fasting plasma glucose, fasting serum insulin and fasting plasma lipid measurements were obtained, and HOMA-IR was calculated. The GRS53 was examined for association with metabolic traits in children by linear regressions using an additive genetic model. RESULTS: In overweight/obese children and adolescents, the GRS53 associated with higher HOMA-IR (ß = 0.109 ± 0.050 (SE); p = 2.73 × 10-2), fasting plasma glucose (ß = 0.010 ± 0.005 mmol/l; p = 2.51 × 10-2) and systolic BP SD score (ß = 0.026 ± 0.012; p = 3.32 × 10-2) as well as lower HDL-cholesterol (ß = -0.008 ± 0.003 mmol/l; p = 1.23 × 10-3), total fat-mass percentage (ß = -0.143 ± 0.054%; p = 9.15 × 10-3) and fat-mass percentage in the legs (ß = -0.197 ± 0.055%; p = 4.09 × 10-4). In the population-based sample of children, the GRS53 only associated with lower HDL-cholesterol concentrations (ß = -0.007 ± 0.003 mmol/l; p = 1.79 × 10-2). CONCLUSIONS/INTERPRETATION: An adult-based GRS comprising 53 insulin resistance susceptibility SNPs associates with insulin resistance, markers of the metabolic syndrome and altered fat distribution in a sample of Danish children and adolescents who were overweight or obese.

14.
J Endocr Soc ; 1(6): 681-690, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29264522

RESUMO

Context: Gestational diabetes mellitus (GDM), defined as any degree of glucose intolerance with first recognition during pregnancy, is a heterogeneous form of diabetes characterized by various degrees of ß-cell dysfunction. Objectives: We aimed to estimate the prevalence of possibly pathogenic variants in the maturity-onset diabetes of the young genes GCK, HNF1A, HNF4A, HNF1B, and INS among women with GDM. Furthermore, we examined the glucose tolerance status in variant carriers vs noncarriers at follow-up. Design Setting and Patients: We sequenced the coding regions and intron/exon boundaries of GCK, HNF1A, HNF4A, HNF1B, and INS using targeted region capture and next-generation sequencing in 354 Danish women with diet-treated GDM. Glucose tolerance was examined at follow-up 10 years after the index pregnancy. Main Outcome Measures: The prevalence of possibly pathogenic variants in GCK, HNF1A, HNF4A, HNF1B, and INS was estimated, and differences in anthropometric traits, high-sensitivity C-Reactive Protein (CRP), and glucose metabolism were measured. Results: At baseline, 17 possibly disease-causing variants were found in 21 women, revealing a combined GCK, HNF1A, HNF4A, HNF1B, and INS variant prevalence of 5.9% (95% confidence interval: 3.5% to 8.4%). At follow-up, 15 out of 135 women with diabetes (11%) were carriers of variants in GCK, HNF1A, HNF4A, HNF1B, or INS. Conclusions: Almost 6% of Danish women with diet-treated GDM have possibly pathogenic variants in GCK, HNF1A, HNF4A, HNF1B, or INS. These women are at high risk of developing diabetes after pregnancy. Thus screening for variants in GCK, HNF1A, HNF4A, HNF1B, and INS should be considered among women with GDM.

16.
PLoS Genet ; 13(4): e1006528, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28448500

RESUMO

Physical activity (PA) may modify the genetic effects that give rise to increased risk of obesity. To identify adiposity loci whose effects are modified by PA, we performed genome-wide interaction meta-analyses of BMI and BMI-adjusted waist circumference and waist-hip ratio from up to 200,452 adults of European (n = 180,423) or other ancestry (n = 20,029). We standardized PA by categorizing it into a dichotomous variable where, on average, 23% of participants were categorized as inactive and 77% as physically active. While we replicate the interaction with PA for the strongest known obesity-risk locus in the FTO gene, of which the effect is attenuated by ~30% in physically active individuals compared to inactive individuals, we do not identify additional loci that are sensitive to PA. In additional genome-wide meta-analyses adjusting for PA and interaction with PA, we identify 11 novel adiposity loci, suggesting that accounting for PA or other environmental factors that contribute to variation in adiposity may facilitate gene discovery.


Assuntos
Adiposidade/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Exercício , Obesidade/genética , Adiposidade/fisiologia , Índice de Massa Corporal , Epigenômica , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Masculino , Obesidade/fisiopatologia , Circunferência da Cintura , Relação Cintura-Quadril
17.
PLoS One ; 12(3): e0174204, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28333968

RESUMO

BACKGROUND: Hypothyroidism is associated with obesity, and thyroid hormones are involved in the regulation of body composition, including fat mass. Genome-wide association studies (GWAS) in adults have identified 19 and 6 loci associated with plasma concentrations of thyroid stimulating hormone (TSH) and free thyroxine (fT4), respectively. OBJECTIVE: This study aimed to identify and characterize genetic variants associated with circulating TSH and fT4 in Danish children and adolescents and to examine whether these variants associate with obesity. METHODS: Genome-wide association analyses of imputed genotype data with fasting plasma concentrations of TSH and fT4 from a population-based sample of Danish children, adolescents, and young adults, and a group of children, adolescents, and young adults with overweight and obesity were performed (N = 1,764, mean age = 12.0 years [range 2.5-24.7]). Replication was performed in additional comparable samples (N = 2,097, mean age = 11.8 years [1.2-22.8]). Meta-analyses, using linear additive fixed-effect models, were performed on the results of the discovery and replication analyses. RESULTS: No novel loci associated with TSH or fT4 were identified. Four loci previously associated with TSH in adults were confirmed in this study population (PDE10A (rs2983511: ß = 0.112SD, p = 4.8 ∙ 10-16), FOXE1 (rs7847663: ß = 0.223SD, p = 1.5 ∙ 10-20), NR3C2 (rs9968300: ß = 0.194SD), p = 2.4 ∙ 10-11), VEGFA (rs2396083: ß = 0.088SD, p = 2.2 ∙ 10-10)). Effect sizes of variants known to associate with TSH or fT4 in adults showed a similar direction of effect in our cohort of children and adolescents, 11 of which were associated with TSH or fT4 in our study (p<0.0002). None of the TSH or fT4 associated SNPs were associated with obesity in our cohort, indicating no pleiotropic effects of these variants on obesity. CONCLUSION: In a group of Danish children and adolescents, four loci previously associated with plasma TSH concentrations in adults, were associated with plasma TSH concentrations in children, suggesting comparable genetic determinants of thyroid function in adults and children.


Assuntos
Tireotropina/sangue , Tiroxina/sangue , Adolescente , Adulto , Fatores Etários , Índice de Massa Corporal , Criança , Pré-Escolar , Dinamarca , Feminino , Loci Gênicos/genética , Loci Gênicos/fisiologia , Marcadores Genéticos/genética , Predisposição Genética para Doença/genética , Humanos , Masculino , Obesidade Pediátrica/sangue , Obesidade Pediátrica/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto Jovem
18.
BMC Med Genet ; 16: 105, 2015 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-26558825

RESUMO

BACKGROUND: Childhood obesity is a highly heritable disorder, for which the underlying genetic architecture is largely unknown. Four common variants involved in inflammatory-adipokine triggering (IL6 rs2069845, LEPR rs1137100, NAMPT rs3801266, and AMD1 rs2796749) have recently been associated with obesity and related traits in Indian children. The current study aimed to examine the effect of these variants on risk of childhood/juvenile onset obesity and on obesity-related quantitative traits in two Danish cohorts. METHODS: Genotype information was obtained for 1461 young Caucasian men from the Genetics of Overweight Young Adults (GOYA) study (overweight/obese: 739 and normal weight: 722) and the Danish Childhood Obesity Biobank (TDCOB; overweight/obese: 1022 and normal weight: 650). Overweight/obesity was defined as having a body mass index (BMI) ≥25 kg/m(2); among children and youths, this cut-off was defined using age and sex-specific cut-offs corresponding to an adult body mass index ≥25 kg/m(2). Risk of obesity was assessed using a logistic regression model whereas obesity-related quantitative measures were analyzed using a general linear model (based on z-scores) stratifying on the case status and adjusting for age and gender. Meta-analyses were performed using the fixed effects model. RESULTS: No statistically significant association with childhood/juvenile obesity was found for any of the four gene variants among the individual or combined analyses (rs2069845 OR: 0.94 CI: 0.85-1.04; rs1137100 OR: 1.01 CI: 0.90-1.14; rs3801266: 0.96 CI: 0.84-1.10; rs2796749 OR: 1.02 CI: 0.90-1.15; p > 0.05). However, among normal weight children and juvenile men, the LEPR rs1137100 A-allele significantly associated with lower BMI (ß = -0.12, p = 0.0026). CONCLUSIONS: The IL6, LEPR, NAMPT, and AMD1 gene variants previously found to associate among Indian children did not associate with risk of obesity or obesity-related quantitative measures among Caucasian children and juvenile men from Denmark.


Assuntos
Adenosilmetionina Descarboxilase/genética , Citocinas/genética , Interleucina-6/genética , Nicotinamida Fosforribosiltransferase/genética , Obesidade Pediátrica/genética , Receptores para Leptina/genética , Índice de Massa Corporal , Estudos de Casos e Controles , Dinamarca , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Adulto Jovem
19.
PLoS Genet ; 11(1): e1004876, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25625282

RESUMO

Genome wide association studies (GWAS) for fasting glucose (FG) and insulin (FI) have identified common variant signals which explain 4.8% and 1.2% of trait variance, respectively. It is hypothesized that low-frequency and rare variants could contribute substantially to unexplained genetic variance. To test this, we analyzed exome-array data from up to 33,231 non-diabetic individuals of European ancestry. We found exome-wide significant (P<5×10-7) evidence for two loci not previously highlighted by common variant GWAS: GLP1R (p.Ala316Thr, minor allele frequency (MAF)=1.5%) influencing FG levels, and URB2 (p.Glu594Val, MAF = 0.1%) influencing FI levels. Coding variant associations can highlight potential effector genes at (non-coding) GWAS signals. At the G6PC2/ABCB11 locus, we identified multiple coding variants in G6PC2 (p.Val219Leu, p.His177Tyr, and p.Tyr207Ser) influencing FG levels, conditionally independent of each other and the non-coding GWAS signal. In vitro assays demonstrate that these associated coding alleles result in reduced protein abundance via proteasomal degradation, establishing G6PC2 as an effector gene at this locus. Reconciliation of single-variant associations and functional effects was only possible when haplotype phase was considered. In contrast to earlier reports suggesting that, paradoxically, glucose-raising alleles at this locus are protective against type 2 diabetes (T2D), the p.Val219Leu G6PC2 variant displayed a modest but directionally consistent association with T2D risk. Coding variant associations for glycemic traits in GWAS signals highlight PCSK1, RREB1, and ZHX3 as likely effector transcripts. These coding variant association signals do not have a major impact on the trait variance explained, but they do provide valuable biological insights.


Assuntos
Glicemia/genética , Diabetes Mellitus Tipo 2/genética , Glucose-6-Fosfatase/genética , Insulina/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/patologia , Exoma/genética , Frequência do Gene , Estudo de Associação Genômica Ampla , Receptor do Peptídeo Semelhante ao Glucagon 1 , Índice Glicêmico/genética , Humanos , Insulina/genética , Polimorfismo de Nucleotídeo Único , Receptores de Glucagon/genética
20.
BMC Genet ; 15: 13, 2014 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-24476040

RESUMO

BACKGROUND: Monogenic diabetes is a genetic disease often caused by mutations in genes involved in beta-cell function. Correct sub-categorization of the disease is a prerequisite for appropriate treatment and genetic counseling. Target-region capture sequencing is a combination of genomic region enrichment and next generation sequencing which might be used as an efficient way to diagnose various genetic disorders. We aimed to develop a target-region capture sequencing platform to screen 117 selected candidate genes involved in metabolism for mutations and to evaluate its performance using monogenic diabetes as a study-model. RESULTS: The performance of the assay was evaluated in 70 patients carrying known disease causing mutations previously identified in HNF4A, GCK, HNF1A, HNF1B, INS, or KCNJ11. Target regions with a less than 20-fold sequencing depth were either introns or UTRs. When only considering translated regions, the coverage was 100% with a 50-fold minimum depth. Among the 70 analyzed samples, 63 small size single nucleotide polymorphisms and indels as well as 7 large deletions and duplications were identified as being the pathogenic variants. The mutations identified by the present technique were identical with those previously identified through Sanger sequencing and Multiplex Ligation-dependent Probe Amplification. CONCLUSIONS: We hereby demonstrated that the established platform as an accurate and high-throughput gene testing method which might be useful in the clinical diagnosis of monogenic diabetes.


Assuntos
Análise Mutacional de DNA/métodos , Diabetes Mellitus Tipo 2/genética , Duplicação Gênica , Humanos , Mutação INDEL , Polimorfismo de Nucleotídeo Único , Deleção de Sequência
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