TIMM8A and Progressive sensorineural hearing impairment: Mohr-Tranebjaerg syndrome (MTS, MIM: #304700), caused by mutations in Translocase of Inner Mitochondrial Membrane 8 A/Deafness Dystonia Protein 1 (TIMM8A/DDP1), is a rare X-linked recessive disorder characterized by progressive sensorineural hearing impairment starting in early childhood, gradually followed by a broader phenotypic spectrum, including ataxia, dystonia and visual disability [1–4].