PTH and Hypocalcemia: The term PHP was first used to describe a group of patients exhibiting a pattern of hypocalcemia and hyperphosphatemia with a lack of response to exogenous PTH extract in a case report by Albright and colleagues in 1942[12]. PHP should be suspected when the hormonal axis has been optimized through adequate oral calcium intake and vitamin D supplementation; however, downstream effects remain unobserved, i.e., suspicion should be raised for hormonal resistance.