Causes of childhood obesity

Article Outline

• Copyright

Many parents of children who are overweight and obese want to know what underlying metabolic abnormality is responsible. Many pediatricians are unsure of how extensive an evaluation to perform to detect an underlying genetic or metabolic cause for obesity. In this issue, Reinehr et al evaluated pediatric patients referred to an obesity clinic. In over 1400 patients, they found <1% with a syndromal or endocrine disorder. Of those with an underlying cause, 85% presented with short stature compared to only 0.6 percent of the other children evaluated for obesity. Thyroid stimulating hormone and cortisol concentrations were frequently moderately elevated, but were rarely indicative of a metabolic disorder. They also evaluated the children for mutations in the melanocortin-4 receptor gene. They found mutations in 6% of the overweight population. However, the mutations observed appear unlikely to be the underlying cause in overweight.

Also in this issue, Dubern et al report a new homozygous null mutation of the melonocortin-4 receptor gene which was associated with severe, early onset obesity. The parents were found to be heterozygous carriers of the mutation. Although this is unlikely to be a common cause of childhood obesity, such mutations can provide insight into metabolic pathways and their derangement that can contribute to obesity.