[Obesity caused by melanocortin-4 receptor mutations].

Obesity is usually the result of a combination of genetic and lifestyle factors. In monogenic obesity, overweight is caused by a single gene mutation. The most frequent form of monogenic obesity is caused by mutations in the gene that codes for the melanocortin-4 receptor (MC4R gene). Approximately 2% of Dutch children with obesity have a mutation in the MC4R gene. Children with homozygous and 'compound' heterozygous MC4R mutations have a phenotype distinguished by extreme overweight at an early age and hyperphagia. Children with heterozygous MC4R mutations have a more subtle phenotype and are difficult to distinguish clinically from obese children without this mutation. MC4R mutations can be identified by DNA diagnostics.- Drug treatment is not yet available for this condition.