Atypical presentation of Costeff syndrome-severe psychomotor involvement and electrical status epilepticus during slow wave sleep

• We describe a girl with an atypical presentation of Costeff syndrome.
• Costeff syndrome may co-occur with epilepsy.
• Costeff syndrome can have variable phenotype despite identical genotype.
• OPA3 mutations should be tested in all cases with core features of Costeff syndrome.

BackgroundCosteff syndrome or OPA3-related 3-methylglutaconic aciduria is an autosomal recessive neurodegenerative disorder characterized by early onset optic atrophy and choreoathetosis with later onset of ataxia and spasticity. Costeff syndrome is prevalent among Iraqi Jews.MethodsWe describe a 5 year old girl from Syrian Jewish origin with an atypical presentation of Costeff syndrome.ResultsThe patient presented with asymmetric optic atrophy, severe dystonia and choreoathetosis and global developmental regression at the age of 7 months; no achievement of independent walking and only minimal speech; and appearance of electrical status epilepticus during slow wave sleep in the second year of life with further deterioration. She harbors the classic mutation (c.143-1G > C) in the OPA3 gene.ConclusionCosteff syndrome may present in an atypical manner regarding the ethnic origin, clinical manifestations and co-occurrence of epilepsy. Mutations in OPA3 should be evaluated in all cases presenting with the core features of typical Costeff syndrome.