MedGen

Mitochondrial DNA depletion syndrome-16B (MTDPS16B) is an autosomal recessive childhood-onset and progressive neuroophthalmic mtDNA depletion disorder characterized by optic atrophy, mixed polyneuropathy, spinal and cerebellar ataxia, and generalized chorea (Dosekova et al., 2020). [from OMIM]

Progressive external ophthalmoplegia-4 (PEOA4) is an autosomal dominant form of mitochondrial disease that variably affects skeletal muscle, the nervous system, the liver, and the gastrointestinal tract. Age at onset ranges from infancy to adulthood. The phenotype ranges from relatively mild, with adult-onset skeletal muscle weakness and weakness of the external eye muscles, to severe, with a multisystem disorder characterized by delayed psychomotor development, lactic acidosis, constipation, and liver involvement (summary by Young et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal dominant progressive external ophthalmoplegia, see PEOA1 (157640). [from OMIM]