These findings suggest that several variants of ENPP1 have a primary role in mediating insulin resistance and in the development of both obesity and T2D, suggesting that an underlying molecular mechanism is common to both conditions.
In conclusion, our study suggests a potential role of the K121Q polymorphism or derived ENPP1 haplotypes in increased susceptibility to obesity and early impairment of glucose and insulin metabolism in children.
The single nucleotide polymorphism (SNP) K121Q in the ENPP1 gene has been studied in relation to obesity, insulin resistance and other features of MS in several populations with conflicting results.
The K121Q variant of the ectonucleotide pyrophosphatase/ phosphodiesterase 1 (ENPP1) gene is associated with obesity, insulin resistance, and early myocardial infarction.
We genotyped 106 single-nucleotide polymorphisms (SNPs) within ENPP1 in all 439 subjects from the linkage study, and measured association with obesity and metabolic syndrome (MS)-related traits.
Weaker associations were detected between the SNPs rs1541276 in the MC5R, rs1926065 in the MC3R genes and obesity (P = 0.04 and P = 0.03, respectively), and between SNPs rs2236700 in the MC5R, rs2118404 in the POMC, rs943003 in the ENPP1 genes and type 2 diabetes (P = 0.03, P = 0.02 and P = 0.02, respectively); these associations did not, however, remain significant after correction for multiple testing.
In addition, the previously reported ENPP1/PC-1 "risk haplotype" (Q (rs1044498), delT (rs1799774), and G (rs7754561) alleles) was found to be associated with obesity in male, but not in female, subjects (P = 0.035).
Because insulin resistance is a pivotal factor in the development of metabolic syndrome (MS) and impaired glucose tolerance (IGT), we aimed to test the association between the K121Q and rs997509ENPP-1 variants with obesity, MS and IGT in obese children and adolescents.
Although there was no evidence of an association between the ENPP1K121Q variant and the general phenotype of T2D, we did find an association with adult obesity and T2D.
Our study did not replicate the positive association found previously and suggested that K121Q of ENPP1 might not have a major role in the susceptibility to T2D or obesity in the Chinese Han population.
The K121Q polymorphism of the ectoenzyme nucleotide pyrophosphate phosphodiesterase 1 (ENPP1) gene has been studied in relation to insulin resistance, type 2 diabetes, and obesity, and conflicting results were observed in various populations.