Positive Association of Maternal G Protein β3 Subunit 825T Allele with Reduced Head Circumference at Birth

Abstract

G protein beta3 subunit C825T polymorphism, which has previously been studied in association with common disorders in adults such as hypertension and obesity, has been focused upon recently for a possible important role in fetal metabolism. Japanese are characterized by having equal allele frequencies for this polymorphism. In this study, we determined the maternal and infantile genotypes in 342 pairs of normal healthy mothers and their infants, and compared the genotype frequencies with various infantile somatoscopic characteristics converted into SD units according to sex, parity and gestational weeks. We observed an association of the maternal (but not infantile) G protein beta3 subunit 825T allele with reduced head circumference but not with reduced birth weight of the neonate. No association was observed between G protein beta3 subunit C825T polymorphism and various maternal somatoscopic characteristics. Although detailed mechanism of this association requires further research, our results suggest that expression of the beta3 subunit 825T allele in the mother may exert influence on fetal metabolic environment, perhaps through changes in the maternal uterine environment, or on maternal metabolism.