Effect of the melanocortin-3 receptor C17A and G241A variants on weight loss in childhood obesity2

• Published in: The American journal of clinical nutrition 2007-04, Vol.85 (4), p.950-953
• Main Authors: Santoro, Nicola, Perrone, Laura, Cirillo, Grazia, Raimondo, Paolo, Amato, Alessandra, Brienza, Carmine, del Giudice, Emanuele Miraglia
• Format: Article
• Language: English
• Subjects: BMI zscore; childhood obesity; MC3Rgene; polymorphism; weight loss
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/85.4.950

Background:The central melanocortin system is critical for the long-term regulation of energy homeostasis. Melanocortin-3 receptor (MC3R) knock-out mice, despite being hypophagic, have increased fat mass and higher feed efficiency than do their wild-type littermates. Objective:The aim was to evaluate whether, in childhood obesity, MC3Rvariants are associated with changes in fatness reduction as a consequence of a weight-reduction program. Design:Molecular screening of the MC3Rcoding region in 184 obese children, 77 girls and 107 boys [x̄ (±SEM) body mass index (BMI; in kg/m2) zscore: 3.3 ± 2.3; age 9.2 ± 2 y], was performed. BMI was evaluated at baseline and after 6 and 12 mo of the weight loss program. Results:No new mutations were found. Two previously described polymorphisms, C17A (Thr6Lys) and G241A (Val81Ile), were observed in 20 patients in almost complete linkage disequilibrium. No significant differences in BMI zscores were observed at baseline of the weight-loss program between the genotypes; however, at follow-up, heterozygotes showed a significantly higher BMI zscore (P= 0.03). When the patients were divided according to the amount of weight lost, a higher prevalence of heterozygotes was observed among subjects who lowered their BMI zscore