Four mutations in exon 6 of ELOVL4 cause Stargardt-like Macular Dystrophy (STGD3), a juvenile form of macular degeneration (26, 27, 28, 29, 50), while five point mutations in exons 4 and 6 cause SCA34 (30, 31, 32, 33, 51), a motor impairment caused by degeneration of neurons in the cerebellum. This evidence concerns the gene ELOVL4 and spinocerebellar ataxia type 34.