We describe an early-onset lethal canine brain disorder characterized by severe progressive epilepsy with status epilepticus, mitochondrial dysfunction, accumulation of Aβ, and neurodegeneration due to a recessive deletion in the nuclear-encoded PITRM1. The affected puppies developed normally in the first 2–3 months of life before the onset of seizures. The gene discussed is PITRM1; the disease is status epilepticus.