Table 1

Childhood early-onset monogenic obesity due to the involvement of the genes belonging to the leptin-melanocortin pathway.

GENE

CHROMOSOME

INHERITANCE

PREVALENCE

PHENOTYPIC FEATURES

LEP

7q31.1

Recessive

Rare

Severe obesity, Hyperphagia, Hypogonadotropic hypogonadism, Central hypothyroidism.

LEPR

1p31

Recessive

1.5%

Severe obesity, Hyperphagia, Hypogonadotropic hypogonadism and central hypothyroidism (in some cases)

POMC

2p23.3

Recessive

Rare

Severe obesity, Hyperphagia, Hypothyroidism, ACTH deficiency, Red hair (among Caucasians), Increased growth.

MC4R

18q22

Dominant

2.5%

Severe obesity, Hyperphagia, Excess fat and lean mass, Severe hyperinsulinaemia, Increased growth.

Deletions involving SH2B1

16p11.2

Dominant or de novo

0.5%

Severe obesity, Hyperphagia and severe insulin resistance disproportionate for the degree of obesity, Mild developmental delay (in some cases).

Perrone et al. Italian Journal of Pediatrics 2010 36:43   doi:10.1186/1824-7288-36-43