Novel association between the nonsynonymous A803G polymorphism of the N-acetyltransferase 2 gene and impaired glucose homeostasis in obese children and adolescents

Background: The N-acetyltransferase 2 ( NAT2 ) A803G polymorphism has been associated with decreased insulin sensitivity in a large adult population with the A allele associated with insulin-resistance-related traits.

Objective: Evaluate the association of this polymorphism with anthropometric and metabolic parameters in obese children and adolescents.

Subjects: A total of 748 obese children and adolescents were enrolled.

Methods: Anthropometric and laboratory data were collected. During oral glucose tolerance test, the presence of a possible exaggerated plasma glucose excursion at 1 h (1HPG) or impaired glucose tolerance (IGT) was considered. Homeostasis model assessment, oral disposition index (oDI) and insulinogenic index (IDI) were calculated. Patients were genotyped for the NAT2 A803G polymorphism.

Results: The prevalence of both IGT and elevated-1HPG was higher in children carrying the A803 allele (P = .02 and P = .03). Moreover, this allele was associated with both oDI and IGI reduction (P = .01). No differences among the NAT2 A803G genotypes for the other parameters were shown. Children homozygous for the A allele presented an odds ratio (OR), to show IGT of 4.9 (P = .01). Children both homozygous and heterozygous for the A allele had higher risk to show elevated-1HPG (OR of 2.7, P = .005; and OR = 2.3, P = .005) compared with patients homozygous for the NAT2 803G allele.

Conclusions: NAT2 A803 allele seems to play a role in worsening the destiny of obese children carrying it, predisposing them to elevated-1HPG and IGT and then to a possible future type 2 diabetes mellitus throughout an impairment of pancreatic β-cellular insulin secretion as suggested by oDI and IGI reduction.