Biochemical and in vitro studies demonstrated that PTH regulates 1,25(OH)2D synthesis via G protein signalling.43 A recent study revealed that the ⍺‐subunit of the stimulatory G protein (Gsα) is essential for PTH action in the PT and that the loss of this signalling protein results in PTH resistance, leading to hypocalcemia, reduced serum 1,25(OH)2D and elevated serum PTH. This evidence concerns the gene PTH and Hypocalcemia.