Abstract
Hereditary deficiencies in vitamin D action are rare, usually autosomal-recessive disorders manifested clinically as hypocalcemic rickets in patients with no history of vitamin D deficiency. They could be the end result of basically two pathophysiological mechanisms: 1. Defects in the biosynthesis or degradation of 1,25(OH)2 vitamin D, the active hormonal form of vitamin D. These patients could be cured completely via treatment with high doses of vitamin D, and in cases of defects in calcitriol biosynthesis, by physiological replacement doses of calcitriol. Remission in these patients is dependent on continuous treatment as detailed above. Thus, it is suggested that the name hereditary vitamin D-dependent rickets is used to describe this abnormality. 2. Defects along the long and complex chain of interaction of calcitriol and its target tissues. Less than 50% of patients will respond to treatment with very high doses of calcitriol. Serum levels of calcitriol are high to very high. Thus, it is suggested that this variety of defects is referred to as hereditary calcitriol-resistant rickets. The importance of studying these very rare disorders in vitamin D metabolism and action is that it opens up the possibility of revealing the physiology of vitamin D in human beings.
Original language | English |
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Title of host publication | Principles of Bone Biology |
Publisher | Elsevier |
Pages | 1507-1527 |
Number of pages | 21 |
ISBN (Electronic) | 9780128148419 |
DOIs | |
State | Published - 1 Jan 2019 |
Keywords
- 25-Hydroxyvitamin D 1-alpha hydroxylase
- Hereditary calcitriol-resistant rickets (HCRR)
- Hereditary vitamin D-dependent rickets (HVDDR)
- Hypocalcemic rickets
- Rickets
- Vitamin D 25-hydroxylase
- Vitamin D receptor (VDR)