Gene Defect Linked to Childhood Obesity

New research suggests that some cases of childhood obesity may be due to a congenital deficiency of the leptin receptor. Leptin, a hormone produced by adipose tissue, is intimately involved in appetite and energy metabolism.

Researchers looked for mutations in the leptin-receptor (LEPR) gene in 300 subjects with hyperphagia and early-onset obesity. The mutation was found in eight people, for a prevalence rate of about 3%. Aside from severe early-onset obesity and hyperphagia, distinguishing characteristics of people with a defective LEPR gene also have “alterations in immune function” and delayed puberty due to hypogonadism. Levels of leptin cannot be used as a marker of LEPR deficiency, as serum leptin levels were within the range predicted by elevated fat mass.

“Congenital leptin-receptor deficiency should be considered in the differential diagnosis of any child with hyperphagia and severe obesity in the absence of developmental delay or dysmorphism,” the researchers conclude.

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