Five individuals from 2 unrelated pedigrees in our cohort carry the biallelic E149Kfs*18 frameshift and R495W substitution and manifest an early onset, progressive myoclonus epilepsy (PME) and ataxia, therefore, expanding the neurological phenotypes associated with ATP6V0A1 variants beyond the more severe developmental and epileptic encephalopathy observed in the de novo cases. The gene discussed is ATP6V0A1; the disease is progressive myoclonus epilepsy.