Infantile-onset spinocerebellar ataxia (IOSCA) is a hereditary neurological disorder with early and severe involvement of both the peripheral and central nervous systems. It has only been described in Finnish families. The disease is mitochondrial DNA depletion syndrome 7 (hepatocerebral type) (MONDO_0010060). Also known as: IOSCA, OHAHA syndrome, Ohaha syndrome, TWNK autosomal recessive degenerative and progressive cerebellar ataxia, autosomal recessive degenerative and progressive cerebellar ataxia caused by mutation in TWNK, infantile onset spinocerebellar ataxia, mitochondrial DNA depletion syndrome type 7, ophthalmoplegia-hypotonia-ataxia-hypoacusis-athetosis syndrome.