VPS13D and Autosomal recessive cerebellar ataxia - saccadic intrusion: Mutations in each of the four members can cause movement disorders, among which VPS13D deficiency causes either autosomal recessive spinocerebellar ataxia-4 (SCAR4) [381–384], or hereditary spastic paraplegia (HSP) [384–386], both are characterized by cerebellar ataxia.