All four variants were previously reported to cause—episodic ataxia (EA) in SCN2A; alternating hemiplegia of childhood in ATP1A3; Refsum disease (RD) in PEX7; and episodic ataxia type 1 (EA1) in KCNA1. In detail:. Here, KCNA1 is linked to episodic ataxia type 1.