HMGA2 and obesity due to melanocortin 4 receptor deficiency: The same group also demonstrated that disruption of Hmga2 gene caused a dramatic reduction in obesity of leptin-deficient mice (Lepob/Lepob) in a gene dosage dependent manner: Hmga2+/+Lepob/Lepob mice weighed over three times more than Hmga2-/-Lepob/Lepob animals, and the weight of Hmga2+/-Lepob/Lepob mice was in between [3].