Related Experiment Video
Updated: Aug 9, 2026
A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
Vitamin D receptor gene polymorphism and calcium metabolism in sarcoidosis patients
1Second Department of Internal Medicine, Nagoya City Univ. Medical School, Japan.
Background:
Hypercalcemia has been recognized as an important complication of sarcoidosis, caused by overproduction of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) at sites of granulomatous reactions. Polymorphism of the vitamin D receptor (VDR) gene has recently been shown to be related to bone mineral density, and also associated with hyperparathyroidism and risk of granulomatous disease. In light of the possible impact on hypercalcemia of sarcoidosis, an investigation of calcium metabolism and polymorphism of the VDR gene in sarcoidosis patients was carried out.
Methods:
Genotypes were determined using the polymerase chain reaction and restriction fragment length polymorphism. Maximum calcium, 1,25(OH)2D3, and intact PTH levels were also determined.
Results:
Depressed PTH levels were found in sarcoidosis patients, especially in those with the bb genotype, but there was no difference in 1,25(OH)2D3 levels among the VDR genotypes, and this polymorphism also had no association with onset of hypercalcemia.
Conclusion:
From these results, we speculate that although the VDR gene polymorphism may affect the serum PTH level, it is not a risk factor for hypercalcemia in sarcoidosis.
Related Concept Videos
01:23Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
01:21Skeleton and Calcium Homeostasis
01:25Role of Vitamins in Maintaining Bone Health
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
00:51Synthesis and Functions of Calcitonin
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
01:29Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase