Loss of key chunks of DNA appears to lead to severe obesity in children, British researchers report (Bochukova EG et al. Nature. doi:10.1038/nature 08689 [published online ahead of print December 6, 2009]).
The researchers scanned the genomes of 300 children who had become severely obese early in life and 7366 apparently healthy controls for copy number variants, large DNA segments that are either deleted or duplicated in the genome. Such mutations, which can span several genes, are known to cause such disorders as autism and intellectual disability.
Stephenson J. Severe Childhood Obesity. JAMA. 2010;303(3):215. doi:10.1001/jama.2009.1964