We have genotyped three single nucleotide polymorphisms associated with type 2 diabetes in a large type 1 diabetic family collection of European descent: Gly972Arg in the insulin receptor substrate 1 (IRS1) gene, Glu23Lys in the potassium inwardly-rectifying channel gene (KCNJ11), and Pro12Ala in the peroxisome proliferative-activated receptor gamma2 gene (PPARG2).
IRS1 G972R polymorphism and type 2 diabetes: a paradigm for the difficult ascertainment of the contribution to disease susceptibility of 'low-frequency-low-risk' variants.
The G972R variant of the IRS1 gene might represent a modifier locus among women who are heterozygous carriers of CYP21 mutations, potentially increasing their risk of developing AA excess in PCOS.
The most commonly detected polymorphism in human insulin receptor substrate-1 (IRS-1), a glycine to arginine change at codon 972 (G972R), is associated with an increased risk of Type 2 diabetes and insulin resistance.
This study confirms in a large and ethnically homogeneous sample that IRS1 G972R polymorphism is associated with failure to OAD among patients with T2D.
Moreover, cerebrocortical insulin resistance is found in individuals with the Gly972Arg polymorphism in IRS-1, which is considered a type 2 diabetes risk gene.
Thus, our data suggest that the common T2D susceptibility polymorphism of TCF7L2 (rs7903146 C/T) gene, and the G972R polymorphism of the IRS1 gene, seem to predispose to GDM in Greek women.
We further investigated the effect of interaction of IRS-1 Gly972Arg and IRS-2 Gly1057Asp on the risk of PCOS and found that women carried IRS-1 Gly/Arg or IRS-2 Asp/Asp or carried both IRS-1 Gly/Arg and IRS-2 Asp/Asp had a much higher risk of PCOS compared with their counterpart, respectively (OR 2.49, 95% C.I.
Despite several reports of association of the G972R polymorphism in its gene IRS1 with type 2 diabetes, we and others have not observed this association in well-powered samples.
The results showed a significant difference in the genotype distribution and allele frequency between the T2DM cases and controls for single nucleotide polymorphism (SNP) rs1801278 (OR 17.61, 95% CI 8.06-38.4, p < 0.001).
The PPARG Pro12 is associated with insulin resistance and this polymorphism interacts with IRS1 Gly972Arg, to increase the risk of T2DM in the mixed-ancestry population of South Africa.
Two mutations of the IRS-1 gene (Gly(972)Arg and Ala(513)Pro) have been described, although their roles in the development of insulin resistance and non-insulin-dependent diabetes mellitus (NIDDM) remain controversial.
Several polymorphisms in the IRS genes have been identified, but only the Gly-->Arg972 substitution of IRS-1, interacting with environmental factors, seems to have a pathogenic role in the development of type 2 diabetes.
Heterozygosity for the Gly972Arg variant of the IRS1 gene showed the strongest association for T2D in both analyzed samples (OR = 2.43, 95% CI 1.12-5.26 and 2.64, 95% CI 1.37-5.10, respectively).
One hundred consecutive PCOS women (diagnosed by Rotterdam criteria) and 45 age-matched healthy women were genotyped for two polymorphisms: Gly972Arg of IRS-1 and Lys121Gln of PC-1.
Prevalence of the insulin receptor substrate-1(IRS-1) Gly972Arg and the insulin receptor substrate-2(IRS-2) Gly1057Asp polymorphisms in PCOS patients and non-diabetic healthy women.
Two SSCP variants that change the sequence of the protein, delta S686/687 (deletion of the codons for serine-686 and 687) and G972R, were identified in two different NIDDM subjects, both whom were also heterozygous for the V101I polymorphisms in GLUT2.