NARP syndrome and adult-onset generalised seizures.

The neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) syndrome is a maternally inherited disorder attributable to a heteroplasmic mtDNA point mutation. Catastrophic epilepsy may accompany severe, early onset forms of NARP, but seizures seem to be rare in cases with adolescent and adult onset. We describe a patient who developed clumsiness and visual problems in her teens. She had no clinical seizures but an EEG showed generalized spike and wave discharges. At this time the patient remained without a specific diagnosis. At the age of 21, the patient developed progressive ataxia and she also experienced a tonic-clonic status epilepticus. Further examinations revealed NARP syndrome. EEG abnormalities may precede adult onset seizures in the NARP syndrome.