ACO2 Mutations: A Novel Phenotype Associating Severe Optic Atrophy and Spastic Paraplegia.

Aconitase 2 ( ACO2 ) encodes the mitochondrial aconitase (ACO2), an enzyme catalyzing interconversion of citrate into isocitrate in the Krebs cycle. ACO2 mutations have been initially associated with infantile cerebellar-retinal degeneration combining optic atrophy, retinal degeneration, severe encephalopathy, epilepsy, and cerebellar ataxia1–3; subsequently, ACO2 mutations have also been associated with milder presentations including isolated optic atrophy2 or cerebellar ataxia without optic atrophy.4 We report here a patient presenting with a novel ACO2 phenotype associating optic atrophy with spastic paraplegia. This article is dedicated to the memory of Pr Christian Hamel, who died prematurely on August 15, 2017.