Mohr-Tranebjaerg syndrome (Orphanet_52368) (MTS) 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.