The Gly972Arg polymorphism in insulin receptor substrate-1 is associated with decreased birth weight in a population-based sample of Brazilian newborns

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 (3.1+1 +/- 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