| Calcium-Sensing Receptor Gene Polymorphism is Associated with the Parathyroid Response to Low Calcium Dialysate in Hemodialysis Patients with Low Parathyroid Hormone Secretion |
| Tae Jin Park, M.D.1, Jang Won Seo, M.D.1, Kwan Mi Pack, M.D.2, Jai Won Chang, M.D.2, Won Seok Yang, M.D.2, Soon Bae Kim, M.D.2, Sang Koo Lee, M.D.2, Su-Kil Park, M.D.2 and Jung Sik Park, M.D.2 |
Kidney Research Center, Departments of Internal Medicine1
College of Medicine, Hallym University, Chunchon, Departments of Internal Medicine2
Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea |
| 부갑상선호르몬 분비가 저하된 혈액투석 환자에서 저칼슘투석액 사용시 칼슘감지수용체의 유전자 다형성에 따른 호르몬 분비의 변화 |
| 박태진1 |
| 한림대학교 의과대학 내과학교실, 신장연구소1, 울산대학교 의과대학 서울아산병원 내과2 |
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| Abstract |
Purpose
: Low level of parathyroid hormone (PTH) is a risk factor that might cause hip fracture in dialysis patients. Low calcium dialysate (LCD) has been suggested as an approach to increase PTH level. The calcium- sensing receptor (CaSR) polymorphism is known to be associated with the sensitivity to extracellular calcium.
Methods
: We prospectively investigated the role of genetic polymorphism of CaSR codon 990 as one cause of the different parathyroid responses to LCD in maintenance hemodialysis (HD) patients. 48 patients, using 3.5 mEq/L calcium dialysate, with intact PTH below 100 pg/ml for the last one year underwent HD sessions on 2.5 mEq/L calcium dialysate for 12 weeks. Serum intact PTH, total calcium, phosphorus, alkaline phosphatase (ALP) and bone-specific ALP (BAP) were measured monthly. The CaSR gene from peripheral lymphocytes was amplified to confirm the genotype by polymerase chain reaction.
Results
: According to the CaSR genetic polymorphism, subjects were divided into 3 groups, A/A (14.6 %), A/G (45.8%) and G/G (39.6%). Twelve weeks later, intact PTH (48.5±25.4 to 89.0±49.4 pg/mL, p<0.01), and ALP (78.7±25.7 to 87.4±27.2 IU/L, p<0.01) increased significantly in G/G group, but not in non-G/G groups. However, BAP significantly increased in both G/G group (24.3±11.9 to 29.5± 10.6 U/L, p<0.01) and in non-G/G groups (21.4±4.5 to 26.1±9.1 U/L, p<0.01). During the study period, levels of corrected total calcium and phosphorus were not significantly changed.
Conclusion
: The CaSR polymorphism, G/G genotype, strongly influenced the responsiveness of parathyroid gland to LCD, compared with non-G/G genotypes. However, bone formation may occur actively on LCD, irrespective of CaSR genetic polymorphism. |
| Key Words:
Calcium-sensing receptor, Genetic polymorphism, End-stage renal disease, Hyperparathyroidism |
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