In that obesity is considered to be a highly heritable and genetically heterogeneous disorder, Sadaf Farooqi, from Addenbrooke’s Hospital (United Kingdom), and colleagues studied 300 children with severe obesity, which often is blamed on abusive overfeeding. The team examined each child’s entire genome, comparing their DNA profiles with normal-weight peers, aiming to identify deletions or duplications of DNA, known as copy number variants (CNVs). The researchers identified on a missing part gene on chromosome 16 called SH2B1, which normally has an integral function in regulating weight and maintaining blood sugar levels. Writing that: “Deletion carriers exhibited hyperphagia and severe insulin resistance disproportionate for the degree of obesity,” the team concludes that: “We show that copy number variation contributes significantly to the genetic architecture of human obesity.”
Lost Segment of DNA May Be Cause of Obesity
Elena G. Bochukova, Ni Huang, Julia Keogh, Elana Henning, Carolin Purmann, Kasia Blaszczyk, Sadia Saeed, Julian Hamilton-Shield, Jill Clayton-Smith, Stephen O’Rahilly, et al. “Large, rare chromosomal deletions associated with severe early-onset obesity.” Nature, 6 December 2009; doi:10.1038/nature08689 Letter.
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