INTERACTIVE EFFECT OF ESTRADIOL AND VITAMIN-D-RECEPTOR GENE POLYMORPHISMS AS A POSSIBLE DETERMINANT OF GROWTH IN MALE AND FEMALE INFANTS

An association between vitamin D receptor (VDR) gene polymorphism and body size has been observed in infants. We hypothesized that the estra diol receptor (ER) gene is another determinant of infant growth and th at the effects of the VDR and ER genotypes may interact with each othe r. The ER genotype (PvuII and XbaI sites), VDR genotype (BsmI site), a nd body size during the first 2 yr of life were analyzed in 161 health y Caucasian full-term babies homozygous for the BsmI polymorphism of t he VDR gene (BB or bb). There was no significant association between E R polymorphism and 1) body weight in boys and girls, 2) body length in girls, or 3)body length in boys with a bb genotype. In contrast, ER p olymorphism and body length were significantly associated in BE boys. Boys with the BBpp genotype were shorter at birth (P < 0.005) and at 1 0 months of age (P < 0.001) than boys with other genotypes. They were even shorter than girls with the same genotype. These results indicate some degree of interaction between the effects of the VDR and ER gene s, leading to significant variations in body growth during infancy, es pecially in boys.