Monarch Disease Ontology entry MONDO_0012449 (spinocerebellar ataxia type 23) (SCA23) is a very rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I). It is characterized by gait ataxia, dysarthria, slowed saccades, ocular dysmetria, Babinski sign and hyperreflexia. Also known as: SCA23.