ARHGEF9 and familial hemiplegic migraine: In addition to PRRT2, which was implicated in both epilepsy and other paroxysmal disorders, we found four variants in genes that cause paroxysmal disorders other than epilepsy: ATP1A2 (familial hemiplegic migraine, p.Gly366Cys), ATP1A3 (alternating hemiplegia, p.Ile363Thr), GLRA1 (hyperekplexia, p.Met165fs), and ARHGEF9 (hyperekplexia, p.Trp452*).