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rickets type-1; pseudo-vitamin D deficiency
Pathology:
1) inadequate endogenous synthesis of 1,25(OH)2 vit D3
a) 1-alpha-hydroxylation deficiency
b) 25-hydroxylation deficiency
2) reduced tubular resorption of phosphate
3) hyperchloremic acidosis may occur
Genetics:
- autosomal recessive
- associated with defects in CYP27B1
Clinical manifestations:
- rickets begins < 2 years of age
- muscle weakness
Laboratory:
1) serum chemistries
a) serum Ca+2 is low (hyocalcemia)
b) parathyroid hormone (PTH) is elevated
c) alkaline phosphatase is elevated
d) phosphorous is variable
e) 1,25(OH)2vit-D3 is variable
f) hyperchloremia may occur
2) urine chemistries
a) Ca+2 is diminished
b) aminoaciduria may occur
c) urinary cAMP increases normally in response to PTH infusion
Management:
1) calcitriol (observe for hypercalcemia)
2) calcium 0.5-2.0 g QD
General
hereditary rickets
Database Correlations
OMIM correlations
References
- OMIM :accession 264700
- Harrison's Principles of Internal Medicine, 13th ed.
Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1328