Vitamin D receptor BsmI and TagI gene polymorphisms in a Turkish ESRD population: influences on parathyroid hormone response.
BACKGROUND
Clinical presentation and complications of end-stage renal disease patients are influenced by many environmental and genetic factors. In this study we sought to define the frequencies of BsmI and TagI vitamin D receptor gene polymorphisms and their influences on clinical presentations in the Turkish end-stage renal disease population.


METHODS
Hemodialyzed patients (n = 186; 111 male, 75 female) were genotyped for the insertion/deletion BsmI (B --> b, restriction site, exon VIII --> IX), TagI (T --> t, 352 exon IX) vitamin D receptor gene polymorphisms. The previous 12 months of laboratory values (C-reactive protein, intact parathyroid hormone, albumin, calcium, phosphorus, CaxP product) and clinical findings (vitamin D requirement, body weight) were analyzed retrospectively.


RESULTS
Mean age and follow-up periods were 42.1 +/- 12.6 years and 76.3 +/- 43.9 months, respectively. Polymorphism percentages were BsmI; BB/Bb/bb: 28.9/65.3/5.8% and TagI; TT/Tt/tt: 36.7/60.5/2.8%, respectively. Further analysis revealed that the TT variant of TagI was related to hyperparathyroidism (P < .05). Analysis of the data after regrouping patients according to iPTH levels (0 to 249; 250 to 499; > or =500 pg/mL) and hemodialysis duration (<60 versus > or =60 months) revealed an influence of TT variation on hyperparathyroidism as a function of increased hemodialysis duration and higher iPTH levels (P < .005).


CONCLUSIONS
TT variants of the TagI vitamin D receptor gene influence the development of hyperparathyroidism in hemodialysis patients, an influence that becomes more evident in patients with longer hemodialysis duration.
Ozdemir
F N
FN
Baskent University Hospital, Department of Nephrology, Ankara, Turkey.
Sezer
S
S
Atac
B
B
Tutal
E
E
Verdi
H
H
Sahin
F
F
Haberal
M
M
D015252:Deoxyribonucleases, Type II Site-Specific; D005091:Exons; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007676:Kidney Failure, Chronic / Q000235:genetics*; D008297:Male; D010281:Parathyroid Hormone / Q000627:therapeutic use*; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000235:genetics*; D006435:Renal Dialysis; D015183:Restriction Mapping; D017384:Sequence Deletion; D014421:Turkey
D010281:Parathyroid Hormone; D018167:Receptors, Calcitriol; C053864:endodeoxyribonuclease BsmI; D015252:Deoxyribonucleases, Type II Site-Specific