Kırmızıbekmez H, Kendir Demirkol Y, Akgün Doğan Ö, Seymen G, İnan Balcı E, Atla P, Dursun F. Familial early-onset obesity in Turkish children: variants and polymorphisms in the melanocortin-4 receptor (MC4R) gene.
J Pediatr Endocrinol Metab 2022;
35:657-662. [PMID:
35355494 DOI:
10.1515/jpem-2021-0756]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/11/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES
Genetic factors have a key role in childhood obesity with higher rates in children than adults. Among the monogenic types of non-syndromic obesity, melanocortin-4 receptor (MC4R) deficiency is the most frequent cause. Beside pathogenic variants, single-nucleotide polymorphisms in MC4R gene are also associated with lower energy expenditure. The aim of this study was to estimate the frequency of MC4R variants and polymorphisms in a cohort of Turkish children and adolescents with severe early-onset obesity, and to understand the clinical features of patients.
METHODS
Patients, 1-17 years of age, with the onset of obesity before 10 years of age and a body mass index (BMI) standard deviation score (SDS) of >2.3, and who had a family history of early-onset obesity in at least one of their first-degree relatives were included in the study. Beside routine blood tests genetic analyses for MC4R gene were performed.
RESULTS
Analyses of MC4R revealed previously known variations in three (3.5%) patients, and pathogenic polymorphisms related with obesity in four (4.7%) patients. BMI SDS values were between 2.8 and 5.5 SDS in the pathogenic variant carrier group, and 2.8-4.9 SDS in the polymorphism group. Mean BMI SDS in variant-negative group was 3.4 ± 0.82.
CONCLUSIONS
Investigation of the MC4R in individuals with early-onset obesity and presence of obesity first-degree relatives is important. Hypertension is a rare comorbidity compared to other causes. Contrary to studies reporting that insulin resistance was absent or very rare, we found it as a frequent finding in both pathogenic variants and polymorphisms of MC4R.
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