Osteomalacia and rickets result from a deficiency in, FTP, this vitamin important in regulating calcium levels that can be synthesized in the skin or taken in from foods such as fish oil and fortified milk.
Abnormal sensitivity to it is found in sufferers of Williams' syndrome.  One major precursor of it is 7-dehydrocholesterol, which is converted to its most active form by two different hydroxylases in the liver and kidney.  It functions in concert with parathyroid hormone to regulate plasma levels of phosphorus and a cation found in insoluble form in the body as hydroxyapatite.  Osteomalacia and rickets result from a deficiency in, FTP, this vitamin important in regulating calcium levels that can be synthesized in the skin or taken in from foods such as fish oil and fortified milk.
Abnormal sensitivity to it is found in sufferers of Williams' syndrome.  
vitamin D or calciferol