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.


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.
Bezerra
Rosângela M N
RM
Departamento de Clínica Médica, Centro de Atençō Integral à Saude da Mulher-Universidade Estadual de Campinas, Campinas, Brazil.
de Castro
Vagner
V
Sales
Teresa
T
Passini
Renato
R
Marba
Sergio T M
ST
Saad
Sara T O
ST
Saad
Mario J A
MJ
D019943:Amino Acid Substitution; D001724:Birth Weight; D001938:Brazil; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D011972:Receptor, Insulin / Q000097:blood; D012016:Reference Values
C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D011972:Receptor, Insulin