Sequencing of 14 Genes From Leptin Melanocortin Pathway in Severe Obesity in Childhood.

Results of Sequencing of a Large Panel of Genes From Leptin Melanocortin Pathway in Children Suffering From Severe Obesity

About 380 million children and adolescents suffer from overweight and obesity at the global level. Obesity results from the interplay between biological (sex, age, fetal programming, gut microbiota, epigenetics, and genetics) and environmental factors (e.g., unhealthy diet, physical inactivity, stress). Mutations in genes from leptin melanocortin pathway are involved in "non syndromic monogenic obesity", characterized by severe early onset obesity, hyperphagia and endocrine deficiencies. Exact frequencies of mutation in these genes are not precisely evaluated in french children with severe obesity. Moreover new treatment, such seltmelanotide are avalaible in case of certain mutation, leading to a significative weight loss in treated patients.

Obesity is a global health concern that affected more than 650 million adult people and more than 380 million children and adolescents worldwide, with no signs of slowing down despite major investments in health policy. Obestiy is a multifactorial disease, but 40 to 75% of body mass index (BMI) variation is explained by genetic factors.

Mutations in genes from leptin melanocortin pathway lead to "non syndromic monogenic obesity", characterized by severe early onset obesity, hyperphagia and endocrine deficiencies. This pathway plays a central role in regulating mammalian food intake, energy expenditure and body weight regulation. Somes genes are well characterized such LEP gene, LEPR gene, or MC4R but others have been recently described as ADCY3, SIM1, SH2B1, NTRK2, BDNF, KSR2.

The frequency of these mutations are not precisely estimated in a group of french children with severe obesity.

Moreover, a precocious identification of these mutations, could afford, in certain case the possibility of a efficient treatment with setmelanotide, leading to a significant weight loss in treated patients.

Inclusion Criteria:

• severe obesity with BMI > 3SDS

Exclusion Criteria:

• genetic obesity (Prader Willi syndrome, Bardet Biedl syndrome, X fragile syndrome, Alstrom syndrome)
• BMI < 3 SDS
• age < 6 months
• monogenic non syndromic obesity, with mutation in genes of leptin melanocortin pathway previously diagnosed
• cushing syndrome