BB genotype of the vitamin D receptor gene polymorphism postpones parathyroidectomy in hemodialysis patients.
BACKGROUND
Bsml vitamin D receptor (VDR) gene polymorphism has been reported to influence the progression of secondary hyperparathyroidism but it is not known how much the genetic background contributes to the need for parathyroidectomy (PTx). We investigated the influence of VDR gene polymorphism on PTx in patients with different dialysis vintage.


METHODS
We studied 121 parathyroidectomized HD patients ("PTx " group). Patients who had required early parathyroidectomy ("early PTx" group) or late parathyroidectomy ("late PTx" group) were analyzed separately. The cut-off point between these two groups was 89 months (mean time on hemodialysis (HD) before parathyroidectomy). Serum intact parathyroid hormone, calcium, phosphorus and alkaline phosphatase were measured. Bsml genotypes were analyzed by polymerase chain reaction. Statistical analysis was done with univariant analysis of variance (ANOVA) to compare the genotype groups and general factorial ANOVA, entering time on HD as the dependent variable, with genotype, sex, age and chronic renal failure (CRF) etiology as factors. As a control group for the association studies we determined genotypic frequencies in 162 HD patients ("total HD" group), and in a healthy control population of 120 individuals ("healthy" group), tested by contingency table analysis and the chi-square test.


RESULTS
No significant differences were found between the genotypes except for the time on HD. General factorial ANOVA showed that the adjusted means of the time on HD were significantly different for the various genotypes (p = 0.015). The BB genotype was significantly less frequent in the "early PTx " group than in the "total HD" and "late PTx" groups.


CONCLUSIONS
Individuals with the BB genotype can remain longer on HD before they need parathyroidectomy.
Borràs
Mercè
M
Nephrology Service, University Hospital Arnau de Vilanova, Department of Medicine, University of Lleida, Lleida, Spain.
Torregrossa
Vicens
V
Oliveras
Anna
A
Almirall
Jaume
J
Ma Paz
Marco
M
Betriu
Angels
A
Martin
Marisa
M
Muray
Salomé
S
Fibla
Joan
J
Fernández
Elvira
E
D000328:Adult; D000704:Analysis of Variance; D015331:Cohort Studies; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D005838:Genotype; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000175:diagnosis / Q000235:genetics* / Q000601:surgery*; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011336:Probability; D011379:Prognosis; D018167:Receptors, Calcitriol / Q000235:genetics*; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors
D005819:Genetic Markers; D018167:Receptors, Calcitriol