deafness dystonia syndrome (Monarch Disease Ontology term MONDO_0010578) is an X-linked recessive neurodegenerative syndrome characterized by clinical manifestations commencing with early childhood onset hearing loss, followed by adolescent onset progressive dystonia or ataxia, visual impairment from early adulthood onwards and dementia from the 4th decade onwards. Also known as: DDON syndrome, Deafness-Dystonia-Optic Neuronopathy Syndrome, Mohr-Tranebjaerg syndrome, Mohr-Tranebjaerg syndrome, X-linked recessive, deafness dystonia optic atrophy syndrome, deafness dystonia optic neuronopathy syndrome, deafness dystonia optic neuronopathy syndrome (DDON), deafness-dystonia-optic neuronopathy syndrome.