These results show that a) the R236G substitution of POMC gene, although not a major cause of obesity among Italian obese children and adolescents, is associated with early onset obesity, and that b) inherited alterations of the melanocortin signaling pathway, independently of the degree of obesity, do not preclude the possibility to lose weight in mutated individuals following a hypocaloric diet.
These results suggest that the R236G mutation may confer an inherited susceptibility to obesity through the production of an aberrant fusion protein that has the capacity to interfere with central melanocortin signalling.
Highlighting the significance of this gap in knowledge, a single POMC cysteine-to-phenylalanine mutation at position 28 (POMC-C28F) is defective for ER processing and causes early onset obesity in a dominant-negative manner in humans through an unclear mechanism.
Furthermore, both mutations PCSK1-p.Asn180Ser and POMC-p.Phe144Leu, which had previously been reported to be associated with severe obesity, were also identified in this study, but did not co-segregate with obesity.
The common variant rs1042571 in the 3'UTR was significantly associated with BMI in EAs (Overweight: P(adj) = 0.005; Obese: P(adj) = 0.018; Overweight+Obese: P(adj) = 0.002) but not in AAs.
The novel heterozygous mutation Phe144Leu leading to the absence of melanocortin signaling was associated with early-onset obesity suggesting its pathogenic role.
Two novel heterozygous missense mutations in POMC (C28F and L37F) were identified in unrelated probands with early-onset obesity and their overweight or obese family members.
We describe a girl born to consanguineous Pakistani parents with clinical and biochemical features of FGD who is homozygous for the R146H mutation of the adrenocorticotropic hormone (ACTH) receptor gene.
As pioglitazone increases body weight through a direct inhibition of the hypothalamic melanocortin system, we studied hypothalamic neurons producing proopiomelanocortin (POMC) and the endogenous melanocortin inhibitor agouti-related peptide (AGRP), in mice expressing amyotrophic lateral sclerosis-linked mutant SOD1(G86R).