Possible reasons are: (1) Hypomagnesemia due to amphotericin B results in reduced parathyroid hormone (PTH) secretion and increased resistance to PTH in bone tissue. (2) While the etiology remains unclear, low vitamin D levels (1,25-dihydroxy vitamin D) are commonly observed in individuals with hypomagnesemia, potentially resulting in hypocalcemia [168]. The gene discussed is PTH; the disease is familial primary hypomagnesemia.