LEPR and obesity due to melanocortin 4 receptor deficiency: In addition, homozygotes for a mutation in the human leptin receptor gene resulting in the skipping exon16, which produces a truncated protein lacking both the transmembrane and the intracellular domains, show impaired growth hormone secretion, early-onset morbid obesity, and failure of pubertal development.38 Furthermore, common leptin receptor polymorphisms have been shown to be associated with obesity in Caucasians.39