Importantly, the effectiveness of old and new calcilytics on gain-of-function mutations of the CaR was further explored in vitro [265,266], demonstrating that a novel treatment option for patients with activating CaR mutations could be represented by the new quinazolinone-derived calcilytics, which have been shown to be effective in attenuating enhanced cytosolic Ca2+ signalling in four known mutations causing Bartter syndrome (BS) type 5 and autosomal dominant hypocalcemia (ADH). Here, CASR is linked to Bartter syndrome.