CACNA1A and pathologic nystagmus: Variants in the CACNA1A gene were identified in affected individuals from four unrelated families presenting with a spectrum of cognitive impairment including intellectual disability, executive dysfunction, ADHD and/or autism, as well as childhood-onset epileptic encephalopathy with refractory absence epilepsy, febrile seizures, downbeat nystagmus and episodic ataxia, and damaging missense and likely loss-of-functions in CACNA1A, many of which were de novo in origin, have subsequently been identified in individuals presenting with similar phenotypes [16,17,18,19,20].