EVIDENCE OF SELECTION ON PGM1 POLYMORPHISM IN DIABETIC PREGNANCY

Ninety-nine pregnant women with insulin-dependent diabetes mellitus, 8 3 women with gestational diabetes, and a control sample of 315 nondiab etic consecutive puerperae have been studied along with their newborn infants. Neonatal macrosomia is less frequent among diabetic mothers w ith phosphoglucomutase (PGM1) genotype PGM11/*2 than among mothers wi th other PGM1 genotypes. In gestational diabetes the association is mo re evident among younger women than among older women. Diabetic women with the PGM11/*2 genotype show a reduced proportion of heterozygous PGM11/*2 offspring. The phenomenon is much more evident among women u nder 28 years of age and does not depend on the quality of metabolic c ontrol. The data suggest that when both mother and fetus share the PGM 11/*2 genotype, the deleterious effects of a diabetic environment on fetal development are more severe, leading to an early loss of zygotes . This may contribute to a decreased incidence of macromosomia among l ive-born infants delivered by PGM11/*2 mothers.