ELOVL4 and spinocerebellar ataxia type 34: Some patients with STGD3 seem to have early-onset vison loss (1, 2, 3, 4, 10, 34, 66), whereas patients with SCA34 with or without EKV develop relatively slow progression of ataxia, with average onset in adulthood (35, 36, 37, 38, 39, 43, 65).