The G1057D polymorphism of insulin receptor substrate-2 associated with gestational diabetes mellitus

The Gly1057D polymorphism in the insulin receptor substrate-2 (IRS-2) gene has been reported to be associated with insulin resistance, obesity and type 2 diabetes; little is known about its possible association with gestational diabetes mellitus (GDM). To investigate this association we determined the distribution of its genotypes and frequency of alleles in GDM patients.

The study population consisted of 94 subjects; among them were 44 patients with GDM and 50 healthy controls without diabetes. Genomic DNA was extracted from the leukocyte by high pure polymerase chain reaction (PCR) template preparation kit. Genetic polymorphism of IRS-2 G1057D was detected by using PCR-based restriction fragment-length polymorphism (RFLP).

For IRS-2 G1057D polymorphism, there was no significant difference in genotype distribution between GDM patients and controls. The risk for GDM was 2.97 times higher (95% CI: 0.89-9.93, p = 0.076) in the individuals with the IRS-2 DD genotype compared to the GG genotype. Also individuals with the IRS-2 D allele had a significantly higher risk of GDM compared with individuals with the IRS-2 G allele, with a relative risk of 1.86 (95% CI: 1.02-3.37, p = 0.042) for cases compared with population controls.

These results suggest that IRS-2 1057D allele may be associated with GDM.