Association between vitamin D receptor gene polymorphisms and fasting idiopathic hypercalciuria in recurrent stone-forming patients.
OBJECTIVE
To investigate the association between fasting idiopathic hypercalciuria (IHc), defined as IHc in the fasting state associated with normal parathyroid function, and ApaI, BsmI, and FokI polymorphisms of the vitamin D receptor (VDR) gene in 159 hypercalciuric recurrent stone formers. IHc contributes to the formation of calcium kidney stones in more than one half of reported cases.


METHODS
We examined 62 patients with fasting IHc (24 women, mean age 42.8 +/- 11.1 years, body mass index 25.7 +/- 4.8 kg/m2), 97 patients with absorptive IHc (41 women, mean age 43.5 +/- 10.8 years, body mass index 26.1 +/- 4.4 kg/m2), and 124 healthy control subjects (52 women, mean age 41.9 +/- 10.4 years, body mass index 25.4 +/- 5.1 kg/m2) without a history of nephrolithiasis and without IHc. The bone mass density and VDR genotype and haplotype frequencies were determined in the studied populations.


RESULTS
A reduced bone mass density was observed in fasting IHc patients compared with absorptive IHc patients (P = 0.009) and control subjects (P = 0.006). The prevalence of ApaI and BsmI VDR genotypes and alleles in patients with fasting IHc was significantly different statistically (P <0.05) from that observed in patients with absorptive IHc and control subjects, and the ba haplotype was overrepresented in these patients. No statistically significant difference in the distribution of FokI VDR genotypes and alleles was found between the studied groups.


CONCLUSIONS
Our results suggest a genetic association between 3' VDR alleles, fasting IHc, and reduced bone mass density in patients with recurrent stone formation.
Rendina
Domenico
D
Department of Clinical and Experimental Medicine, Federico II University Medical School, Naples, Italy.
Mossetti
Giuseppe
G
Viceconti
Roberto
R
Sorrentino
Mariangela
M
Castaldo
Rosaria
R
Manno
Giuseppe
G
Guadagno
Vincenzo
V
Strazzullo
Pasquale
P
Nunziata
Vincenzo
V
D000328:Adult; D000483:Alleles; D015519:Bone Density / Q000502:physiology; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000652:urine*; D002129:Calcium Oxalate / Q000032:analysis; D002136:Calcium, Dietary / Q000008:administration & dosage; D004252:DNA Mutational Analysis; D004039:Diet, Sodium-Restricted; D005215:Fasting / Q000652:urine; D005260:Female; D006239:Haplotypes; D006801:Humans; D007669:Kidney Calculi / Q000097:blood / Q000737:chemistry / Q000235:genetics* / Q000652:urine; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood / Q000652:urine; D012150:Polymorphism, Restriction Fragment Length; D018167:Receptors, Calcitriol / Q000235:genetics* / Q000502:physiology; D012008:Recurrence; D013972:Thyrotropin / Q000097:blood
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D010710:Phosphates; D018167:Receptors, Calcitriol; D002129:Calcium Oxalate; D013972:Thyrotropin; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium