In addition, 3 heterozygous missense mutations in other genes within the panel were identified (CACNA1A—p.Asp1723Asn and p.Ala987Ser; ATP1A2—p.Glu219Gln) suggesting that these patients have familial hemiplegic migraine (FHM) which has symptomatic features which overlap with CADASIL. Here, CACNA1A is linked to CADASIL.