The Gly972Arg Polymorphism in Insulin Receptor Substrate-1 Is Associated With Decreased Birth Weight in a Population-Based Sample of Brazilian Newborns

The Gly972Arg Polymorphism in Insulin Receptor Substrate-1 Is Associated With Decreased Birth Weight in a Population-Based Sample of Brazilian Newborns Rosângela M.N. Bezerra , PHD 1 , Vagner de Castro , MD 2 , Teresa Sales 1 , Renato Passini, Jr , MD 3 , Sergio T.M. Marba , MD 3 , Sara T.O. Saad , MD 1 and Mario J.A. Saad , MD 1 1 Departamento de Clínica Médica, Centro de Atençō Integral à Saude da Mulher–Universidade Estadual de Campinas, Campinas, Brazil 2 Hemocentro–Universidade Estadual de Campinas, Campinas, Brazil 3 Faculdade de Ciêcias Médicas–Universidade Estadual de Campinas, Campinas, Brazil. Abstract OBJECTIVE —We studied the association between the Gly972Arg polymorphism in insulin receptor substrate-1 (IRS-1) and birth weight in a population-based sample of Brazilian newborns. RESEARCH DESIGN AND METHODS —We studied 194 newborn children with adequate gestational age to identify the association between the Gly972Arg polymorphism and birth weight using PCR—restriction fragment length polymorphism analysis. RESULTS —The data showed that the birth weight was lower in the newborns with the Gly972Arg polymorphism in IRS-1 compared with control subjects (3,141 ±31.8 vs. 3,373 ±80.3 g, P < 0.008). The results also showed that the frequency of this polymorphism was increased in newborns with a birth weight