Case history and clinical findings: A 4-year-old, slightly overweight (BMI 18 kg/m2, BMI SDS 1.29 approximately 90.1 (th) percentile) and otherwise healthy girl presented with accelerated linear growth (99.6 (th) percentile) and hyperphagia due to loss of satiety feeling. These findings are consistent with melanocortin-4 receptor ( MC4R) mutations. GENETIC ANALYSIS AND DIAGNOSIS: We found the partially inactivating mutation Arg (165)Trp by direct sequencing of the MC4R coding region. Interestingly, the patient's mother is also heterozygous for this mutation, but lean (BMI 19 kg/m2).
Treatment and course: Carriers of MC4R mutations develop hyperphagia due to lack of satiety feeling as a result of central dysregulation. The reduction of energy intake and the encouragement of physical activity can be successful to control the body weight.
Conclusion: Early diagnosis can promote lifestyle intervention to prevent the development of obesity even in the presence of a genetic predisposition.