Etiologic risk factors and vitamin D receptor gene polymorphisms in under one-year-old infants with urolithiasis.

The incidence of urinary tract stones in infancy has been increasing in Turkey. Risk factors and vitamin D receptor (VDR) gene polymorphisms were investigated in infants aged < 1 year who had stones. Forty infants with urinary tract stones and 80 infants without stones, aged < 1 year were enrolled in this study. Detailed surveys were taken of all infants, metabolic parameters and ApaI and FokI VDR gene polymorphisms were investigated. Infants with stones tended to be more commonly fed formula and multivitamins (vitamins A, C, D) (p < 0.05). Positive family history came into prominence in the stony group (p < 0.05). There were no significant differences in ApaI and FokI VDR gene polymorphisms between the groups with stones and the control groups. However, CA genotype of ApaI polymorphism was associated with family history and C allele of ApaI was related with family history and hypercalciuria (p < 0.05). Hypercalciuria emerged as an underlying metabolic abnormality in the etiology of stones, and was observed at a rate of 38%. Infants who are given formula and multivitamins for vitamin D supplementation are at increased risk for the formation of urinary tract stones. VDR gene polymorphisms cause the formation of urinary tract stones and affect calcium (Ca) metabolism.