Vitamin D receptor gene polymorphism in hypercalciuric children

Area of Science:

• Genetics
• Endocrinology
• Pediatrics

Background:

• Idiopathic hypercalciuria is a multifactorial condition influenced by genetics and environment.
• The vitamin D receptor (VDR) plays a crucial role in calcium homeostasis.
• VDR gene polymorphisms have been investigated for their association with calcium disorders.

Purpose of the Study:

• To investigate the association between VDR gene polymorphisms (ApaI, BsmI, TaqI) and absorptive hypercalciuria (AH) in children.
• To examine the relationship between these VDR polymorphisms and serum levels of intact parathormone (PTH), osteocalcin, and 25-hydroxyvitamin D.

Main Methods:

• Genotyping of VDR gene polymorphisms (ApaI, BsmI, TaqI) in 80 children with AH and 86 healthy controls.
• Measurement of serum intact PTH, osteocalcin, and 25-hydroxyvitamin D levels.
• Statistical analysis including chi-squared tests and odds ratio calculations.

Main Results:

• A significant difference in the ApaI genotype distribution was found between AH and control groups (chi(2)=7.21, P=0.027).
• The AA genotype of VDR ApaI was associated with a 3.5-fold increased risk of AH (OR 3.5, 95% CI 1.1-11).
• Serum osteocalcin levels were significantly higher in children with the AA genotype compared to Aa/aa genotypes (P=0.02, P=0.05).
• No significant association was found for BsmI and TaqI polymorphisms with AH.

Conclusions:

• The ApaI AA genotype of the VDR gene is associated with an increased risk of absorptive hypercalciuria in children.
• This VDR genotype may also influence bone metabolism, as indicated by higher serum osteocalcin levels.
• VDR gene variations, particularly ApaI, are implicated in the genetic susceptibility to idiopathic hypercalciuria.