Vitamin D Deficiency, Rickets, and Osteomalacia

摘要: Vitamin D is a precursor molecule that can be obtained from the diet or synthesized in skin by process requires ultraviolet radiation sunlight. subsequently activated within body two hydroxylations liver and kidney to yield hormone 1,25-dihydroxyvitamin calcitriol. Calcitriol acts via classical steroid pathway through nuclear receptors regulate level of target gene expression. has many actions but most prominently it controls calcium phosphate absorption intestine. This action determines circulating mineral ions their delivery bone-forming sites mineralize bone. If vitamin deficient its synthesis defective, adequate not delivered thus abnormal undermineralized bone formed. leads metabolic disease rickets childhood osteomalacia adults.