POLG and spinocerebellar ataxia type 20: Alexander disease [5859]Spinocerebellar Ataxia –20 (SCA 20) [6061]POLG mutation [6263]Hereditary spastic paraparesis type 7 (HSP-7) [6465]GM2 Gangliosidosis [66]Neuroferritinopathy [67]Cerebrotendinous Xanthomatosis [68]