CACNA1A and developmental and epileptic encephalopathy, 42: In addition, mutations in the CACNA1A gene can lead to developmental and epileptic encephalopathy-42, which is characterized by various types of refractory seizures usually occurring in the first hours or days of life, with general developmental delay, mental retardation, with or without axial hypotonia, hyperreflexia, tremor, and ataxia (10).