A rare mutation in a brain chemical called β-melanocyte-stimulating hormone (β-MSH) can increase a person's risk of severe early-onset obesity, according to new studies by European researchers (Lee YS et al. Cell Metab. 2006;3:135-140 and Biebermann H et al. Cell Metab. 2006;3:141-146).
One research team found that children with severe early-onset obesity were much likelier than children of normal weight to carry the rare β-MSH mutation; moreover, overweight or obese relatives of children with the mutation were also more likely than normal-weight relatives to carry this gene variant. The group also discovered that the mutation altered the hormone's structure and its ability to stimulate the melanocortin-4 receptor, which previous research had demonstrated plays a critical role in controlling energy balance.
Stephenson J. Obesity-Related Hormone. JAMA. 2006;295(11):1239. doi:10.1001/jama.295.11.1239-d