Bone Abstracts

Hypophosphatasia (HPP) occurs when there is lack of the activity of the alkaline phosphatase protein (ALP). The principal clinical manifestations are seen in the skeleton, although some infants can develop convulsions due to the failure of pyridoxine, cleaved from pyridoxal-5-phosphate by ALP, to enter brain cells.HPP has traditionally been classified by age at presentation, with severe forms being diagnosed in utero or at birth because of fract...

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Classical vitamin D biology relates the active hormone, 1,25-dihydroxvitamin D3, to promotion of calcium homeostasis through actions on the intestine and bone, and regulation of parathyroid hormone production and release. Added to this classical action of vitamin D is the up-regulation of FGF23 production and release by osteocytes as a means of regulation of circulating levels of vitamin D by reducing kidney synthesis of 1,25-dihydroxvitamin D3 and increa...