A patient with a de novo variant in CACNA1A (c.2413G>A, p. A712T) showed a typical DEE phenotype with very early-onset seizures (postnatal 1 month) and a poor response to anti-seizure drugs, whereas another patient with a different de novo CACNA1A variant (c.4031C>A, p. S1344Y) showed episodic ataxia and progressive cerebellar atrophy with juvenile-onset seizures (15 years old) and responded well to anti-seizure drugs. Here, CACNA1A is linked to cerebellar ataxia.