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

  1. Rosângela M.N. Bezerra, PHD1,
  2. Vagner de Castro, MD2,
  3. Teresa Sales1,
  4. Renato Passini, Jr, MD3,
  5. Sergio T.M. Marba, MD3,
  6. Sara T.O. Saad, MD1 and
  7. Mario J.A. Saad, MD1
  1. 1Departamento de Clínica Médica, Centro de Atençō Integral à Saude da Mulher–Universidade Estadual de Campinas, Campinas, Brazil
  2. 2Hemocentro–Universidade Estadual de Campinas, Campinas, Brazil
  3. 3Faculdade 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 <3,000 g (P=0.041).

    CONCLUSIONS—These results suggest that the genotype Gly972Arg may influence birth weight, reinforcing the hypothesis that genetically determined insulin resistance and/or reduced insulin secretion can result in impaired insulin-mediated growth in the fetus.

    Footnotes

    • Address correspondence and reprint requests to Mario J. A. Saad, MD, Departamento de Clínica Médica, FCM-UNICAMP, Campinas, SP, Brazil 13081-970. E-mail: msaad{at}fcm.unicamp.br.

      Receieved for publication 23 May 2001 and accepted in revised form 24 october 2001

      A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

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