CASR and familial primary hypomagnesemia: Our case highlights hypomagnesemia-associated hypocalcemia and hypoparathyroidism, despite the normal serum parathormone level, notably, only 1 case described hypocalcemia with a low parathormone level.[8] Inappropriately normal parathormone levels during hypocalcemia were reported in 3 patients.[6,10,17] Hypomagnesemia may alter the activation of the CaSR, leading to PTH reduction.[28] Hypomagnesemia may reflect a deficiency in PTH secretion, rather than biosynthesis and end-organ resistance to PTH.[29]