CACNA1A and Down syndrome: However, we found two unexpected findings: one patient with an epileptic encephalopathy diagnosed with a channelopathy (CACNA1A (NM_023035.2): p.Arg198Gln/c.593 G > A (heterozygous) and another case diagnosed with a Xq28 duplication syndrome (chrX:154125883–154562336 duplication [436Kb] [heterozygous]).