CACNA1A and migraine, familial hemiplegic, 1: Interestingly, dysfunction of CaV2.1 caused by mutations in CACNA1A has been identified in Familial hemiplegic migraine 1 (FHM1; Ophoff et al., 1996), where altered channel kinetics were identified as a pathomechanism (Kraus et al., 1998, 2000).