Ten calcium channelopathies related to ID/GDD were identified involving the following genes: CACNA1A [18, 19, 39–66], CACNA1C [67–73], CACNA1I [74], CACNA1H [75, 76], CACNA2D2 [77–80], CACNA2D1 [20, 81], CACNA1D [21, 22, 82–84], CACNA1E [85], CACNA1F [86], and CACNA1G [23, 87]. Here, CACNA2D1 is linked to Global developmental delay.