PRRT2 and familial or sporadic hemiplegic migraine: Furthermore numerous heterozygote frameshift, nonsense and missense PRRT2 mutations (including the recurrent frameshift A217PfsX8) were identified in individuals and families with benign infantile seizures (BIS), paroxysmal kinesigenic dyskinesia (PKD), hemiplegic migraine (HM), or episodic ataxia, variably associated (e.g. the ICCA syndrome that associates BIS with PKD) [18]–[21].