Normally, excess 1,25-OH vitamin D would cause an increase in activity of 24-hydroxylase in the kidneys, which converts 25- and 1,25-OH vitamin D to 24,25-OH vitamin D (an inactive form).
necessary for bone and teeth formation
stimulates osteoblastic activity
stimulates calcium AND phosphorous absorption and reabsorption
mineralizes bones and teeth
Deficiency -
Rickets in children - lateral bowing of the legs
The individual may also experience bone pain, dental pain, and be seen to have bead-like costochondral junctions (referred to as “rachitic rosary”). Radiographs of the limbs will demonstrate epiphyseal widening with metaphyseal fraying
osteomalacia in adults
Vit. D resistant rickets
Hypophosphatemic Rickets
X-linked dominant
defective renal absorption of phosphorous in proximal tubule
as PO4 leaks out, it pulls Ca2+ with it -> ricket-like presentation
Case Scenario: