Relationship of insulin receptor substrate-1 and -2 genotypes to phenotypic features of polycystic ovary syndrome.

Ehrmann DA, Tang X, Yoshiuchi I, Cox NJ, Bell GI
J Clin Endocrinol Metab. 2002 87 (9): 4297-300

PMID: 12213887 · DOI:10.1210/jc.2002-020216

Insulin resistance is a key component in the pathogenesis of polycystic ovary syndrome (PCOS) and type 2 diabetes. Polymorphisms in the genes encoding the insulin receptor substrate (IRS) proteins, IRS-1 (Gly(972)Arg) and IRS-2 (Gly(1057)Asp), influence susceptibility to type 2 diabetes. This study was undertaken to assess the influence of these polymorphisms on insulin resistance, glucose tolerance, and androgen levels in nondiabetic PCOS women. We studied 227 PCOS subjects including 126 and 48 nondiabetic white and African-American subjects, respectively. The IRS-1 Gly(972)Arg allele frequencies were identical in whites and African-Americans [0.95 (Gly) and 0.05 (Arg)]. The IRS-2 Gly(1057)Asp allele frequencies were 0.85 (Gly) and 0.15 (Asp) in African-Americans and 0.59 (Gly) and 0.41 (Asp) in whites. There was no association of IRS-1 genotype with any clinical or hormonal measure in nondiabetic white or African-American PCOS subjects. However, nondiabetic subjects with the IRS-2 Gly/Gly genotype had significantly higher 2-h oral glucose tolerance test glucose levels compared with those with Gly/Asp and Asp/Asp genotypes in whites or Gly/Asp genotype in African-Americans (there were no Asp/Asp subjects in our modest size African-American sample). These results suggest that the IRS-2 Gly(1057)Asp polymorphism influences blood glucose levels in nondiabetic white and African-American women with PCOS. Thus, individuals with the common IRS-2 Gly/Gly genotype may be at increased risk of developing type 2 diabetes.

MeSH Terms (22)

Adult Amino Acid Substitution Base Sequence Blood Glucose Body Mass Index Diabetes Mellitus, Type 2 DNA Primers Female Genetic Predisposition to Disease Genotype Glycated Hemoglobin A Homeostasis Humans Insulin Insulin Receptor Substrate Proteins Intracellular Signaling Peptides and Proteins Mutation, Missense Phenotype Phosphoproteins Polycystic Ovary Syndrome Polymorphism, Genetic Receptor, Insulin

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