An autosomal recessive spinocerebellar ataxia caused by disease-causing variants in the SLC9A1 gene, characterized by early-onset cerebellar ataxia, cognitive or developmental delay, seizure, and cerebellar atrophy. Patients may also present with varying degrees of nystagmus, oculomotor apraxia, amelogenesis imperfecta and sensorineural hearing loss. The disease is MONDO_0014572 (Lichtenstein-Knorr syndrome). Also known as: LIKNS, SCAR19, SLC9A1-related spinocerebellar ataxia syndrome, autosomal recessive spinocerebellar ataxia type 19, progressive autosomal recessive ataxia-sensorineural hearing loss syndrome, spinocerebellar ataxia, autosomal recessive 19.