Aim: To screen mutations in the melanocortin 4 receptor (MC4R) in obese and normal-weight Chinese children and adolescents.
Methods: Three hundred Chinese children and adolescents, including 200 obese and 100 healthy non-obese individuals, were evaluated. The coding region of the MC4R gene was amplified by polymerase chain reaction (PCR) and sequenced.
Results: In obese individuals, we detected two novel heterozygous non-synonymous mutations (c.496G>A, resulting in Val166Ile; c.929G>A, resulting in Arg310Lys) and a novel heterozygous non-sense mutation (c.831T>A, resulting in a premature stop codon Cys277Stop). In both obese individuals and controls, a novel heterozygous non-synonymous mutation (c.68T>G, resulting in Leu23Arg, 0.5 and 1%, respectively) and the Val103Ile polymorphism (c.307G>A, 3 and 2%, respectively) were found. There was no difference in alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), cholesterol (CHOL) and whole body insulin sensitivity index (WBISI) between obese individuals with and without mutation. The prevalence for heterozygous MC4R mutations was 1.5% in the obese.
Conclusions: Two novel heterozygous non-synonymous mutations (Val166Ile; Arg310Lys) and a novel heterozygous non-sense mutation (Cys277Stop) were detected in Chinese obese individuals. Leu23Arg variant might be a polymorphism in the Chinese population. There were no differences between clinical and biochemical profiles in the heterozygous mutations and the wild type.