In conclusion, we have identified a FHH2‐causing mutation, which affects the Gα11 switch region and disrupts PLC‐mediated signaling, and have also shown that cinacalcet can rectify these signaling disturbances and be used successfully to treat the hypercalcemia caused by this germline loss‐of‐function Gα11 mutation. This evidence concerns the gene HSPG2 and hypercalcemia disease.