Hebebrand, J. (Joahnnes)
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- A novel nonsense mutation in the melanocortin-4 receptor associated with obesity in a Spanish population(Nature Publishing Group, 2003) Martinez, J.A. (José Alfredo); Hinney, A. (Anke); Hebebrand, J. (Joahnnes); Forga, L. (Luis); Marti-del-Moral, A. (Amelia); Corbalan, M. (M.S.)BACKGROUND: In recent years, several groups have reported dominant inheritance of obesity conferred by missense, nonsense and frameshift mutations in the melanocortin 4 receptor gene (MC4R). Hence, MC4R is involved in the most common monogenic form of human obesity described so far. OBJECTIVES: In this context, we screened a Spanish population, composed of obese subjects and normal weight controls, for mutations in the MC4-R by single-strand conformational polymorphism (SSCP). SUBJECTS AND METHODS: Overall 313 individuals, 159 obese subjects (body mass index: BMI: 37.6 kg/m2, 95% CI: 36.7–38.5 kg/m2) and 154 normal weight control subjects (BMI: 22.3 kg/m2, 95% CI: 22.0–22.6 kg/m2) were screened for MC4-R mutations. RESULTS: We detected a novel nonsense mutation at codon 16 of the MC4-R in an obese female (BMI: 30.0 kg/m2) and a previously described missense mutation (Val-253-Ile) located within the sixth trans-membrane domain of the MC4-R in a normal weight individual (BMI: 19.0 kg/m2). The polymorphism Val-103-Ile was detected in one obese individual, while four subjects (two cases and two controls) with the polymorphism Ile-251-Leu were found. CONCLUSIONS: We have identified a novel nonsense mutation (Trp-16-Stop) that, based on previously described frameshift and nonsense mutations, most likely results in dominantly inherited obesity. Within this Spanish population, the frequency of the Ile-251-Leu polymorphism of the MC4R was similar in obese and control subjects (about 1.3%), while the polymorphism Val-103-Ile was only detected in an obese individual (0.6%).
- A novel mutation Thr162Arg of the melanocortin 4 receptor gene in a Spanish children and adolescent population(Wiley Blackwell, 2007) Martinez, J.A. (José Alfredo); Wermter, A.K. (A.K.); Hinney, A. (Anke); Moreno-Aliaga, M. J. (María Jesús); Hebebrand, J. (Joahnnes); Ochoa, M.C. (María Carmen); Razquin, C. (Cristina); Azcona-San-Julian, M.C. (María Cristina); Brumm, H. (H.); Biebermann, H. (H.); Grupo de Estudio Navarro de la Obesidad Infantil (GENOI); Marti-del-Moral, A. (Amelia)Objective The melanocortin 4 receptor gene (MC4R) is involved in body weight regulation. While many studies associated MC4R mutations with childhood obesity, information on MC4R mutations in Spanish children and adolescents is lacking. Our objective was to screen a population of children and adolescents from the north of Spain (Navarra) for MC4R mutations and to study the phenotypes of carriers and their families. In addition, functional assays were performed for a novel MC4R mutation. Methods The study was composed of 451 Spanish children and adolescents (49% boys), aged 5–18 year. According to the International Obesity Task Force (IOTF) criteria, the groups included 160 obese, 132 overweight and 159 normal-weight control subjects. Results One novel (Thr162Arg) and three known nonsynonymous mutations in the MC4R gene (Ser30Phe, Thr150Ile, Ala244Glu) were detected heterozygously. The MC4R mutations were found in three male (one obese and two overweight) and two female subjects (one obese and one overweight). The novel mutation did not appear to lead to an impaired receptor function. An unequivocal relationship of MC4R mutations with obesity in pedigrees together with an impaired function of the encoded receptor could not be established for any of the mutations. Conclusions The presence of heterozygous MC4R mutations in obese and overweight subjects indicates that these mutations may be a susceptibility factor for obesity development, but lifestyle factors, such as exercise or sedentary activities, may modify their effect.
- Melanocortin-4 Receptor and Lipocalin 2 Gene Variants in Spanish Children with Abdominal Obesity: Effects on BMI-SDS after a Lifestyle Intervention(MDPI AG, 2019) Hinney, A. (Anke); Hebebrand, J. (Joahnnes); Giuranna, J. (Johanna); Azcona-San-Julian, M.C. (María Cristina); Ojeda-Rodríguez, A. (Ana); Morell-Azanza, L. (Lydia); Marti-del-Moral, A. (Amelia)Mutations leading to a reduced function of the melanocortin-4 receptor (MC4R) exert a major gene effect on extreme obesity. Recently it was shown that the bone derived hormone lipocalin 2 (LCN2) binds to the MC4R and activates a MC4R dependent anorexigenic pathway. We identified mutations in both genes and screened the effects of MC4R and LCN2 mutations on eating behavior and weight change after a lifestyle intervention. One hundred and twelve children (11.24 ± 2.6 years, BMI-SDS 2.91 ± 1.07) with abdominal obesity participated in a lifestyle intervention. MC4R and LCN2 coding regions were screened by Sanger sequencing. Eating behavior was assessed at baseline with the Children Eating Behavior Questionnaire (CEBQ). We detected three previously described non-synonymous MC4R variants (Glu42Lys, Thr150Ile, and Arg305Gln) and one non-synonymous polymorphism (Ile251Leu). Regarding LCN2, one known non-synonymous variant (Thr124Met) was detected. Eating behavior was described in carriers of the MC4R and LCN2 mutation and in non-carriers. MC4R and LCN2 mutations were detected in 2.42% and 0.84%, respectively, of Spanish children with abdominal obesity. A number of subjects with functional mutation variants in MC4R and LCN2 were able to achieve a reduction in BMI-SDS after a lifestyle intervention.
- The ABCD of obesity: An EASO position statement on a diagnostic term with clinical and scientific implications(S. Karger AG, 2019) Farpour-Lambert, N. (Nathalie); Busetto, L. (Luca); Woodward, E. (Euan); Frühbeck, G. (Gema); Yumuk, V. (Volkan); Halford, J.C.G. (Jason C. G.); Hebebrand, J. (Joahnnes); Blaak, E.E. (Ellen E.); Toplak, H. (Hermann); Dicker, D. (Dror); Goossens, G.H. (Gijs H.)Obesity is a frequent, serious, complex, relapsing, and chronic disease process that represents a major public health problem. The coining of obesity as an adiposity-based chronic disease (ABCD) is of particular relevance being in line with EASO’s proposal to improve the International Classification of Diseases ICD-11 diagnostic criteria for obesity based on three dimensions, namely etiology, degree of adiposity, and health risks. The body mass index as a unique measurement of obesity does not reflect the whole complexity of the disease. Obesity complications are mainly determined by 2 pathological processes, i.e., physical forces (fat mass disease) as well as endocrine and immune responses (sick fat disease), which are embedded in a cultural and physical context leading to a specific ABCD stage.
- Meta-analysis on the effect of the N363S polymorphism of the glucocorticoid receptor gene (GRL) on human obesity.(BioMed Central, 2006) Martinez, J.A. (José Alfredo); Martinez-Gonzalez, M.A. (Miguel Ángel); Hinney, A. (Anke); Hebebrand, J. (Joahnnes); Ochoa, M.C. (María Carmen); Sanchez-Villegas, A. (Almudena); Marti-del-Moral, A. (Amelia)BACKGROUND: Since both excess glucocorticoid secretion and central obesity are clinical features of some obese patients, it is worthwhile to study a possible association of glucocorticoid receptor gene (GRL) variants with obesity. Previous studies have linked the N363S variant of the GRL gene to increased glucocorticoid effects such as higher body fat, a lower lean-body mass and a larger insulin response to dexamethasone. However, contradictory findings have been also reported about the association between this variant and obesity phenotypes. Individual studies may lack statistical power which may result in disparate results. This limitation can be overcome using meta-analytic techniques. METHODS: We conducted a meta-analysis to assess the association between the N363S polymorphism of the GRL gene and obesity risk. In addition to published research, we included also our own unpublished data -three novel case-control studies- in the meta-analysis The new case-control studies were conducted in German and Spanish children, adolescents and adults (total number of subjects: 1,117). Genotype was assessed by PCR-RFLP (Tsp509I). The final formal meta-analysis included a total number of 5,909 individuals. RESULTS: The meta-analysis revealed a higher body mass index (BMI) with an overall estimation of +0.18 kg/m2 (95% CI: +0.004 to +0.35) for homo-/heterozygous carriers of the 363S allele of the GRL gene in comparison to non-carriers. Moreover, differences in pooled BMI were statistically significant and positive when considering one-group studies from the literature in which participants had a BMI below 27 kg/m2 (+ 0.41 kg/m2 [95% CI +0.17 to +0.66]), but the differences in BMI were negative when only our novel data from younger (aged under 45) and normal weight subjects were pooled together (-0.50 kg/m2 [95% CI -0.84 to -0.17]). The overall risk for obesity for homo-/heterozygous carriers of the 363S allele was not statistically significant in the meta-analysis (pooled OR = 1.02; 95% CI: 0.56-1.87). CONCLUSION: Although certain genotypic effects could be population-specific, we conclude that there is no compelling evidence that the N363S polymorphism of the GRL gene is associated with either average BMI or obesity risk.