A 3-BASE-PAIR DELETION IN THE PERIPHERIN-RDS GENE IN ONE FORM OF RETINITIS-PIGMENTOSA

THE group of retinopathies termed retinitis pigmentosa (RP) greatly contribute to visual dysfunction in man with a frequency of roughly 1 in 4,000 (refs 1, 2). We mapped the first autosomal dominant RP (adRP) gene to chromosome 3q (refs 3, 4), close to the gene encoding rhodopsin, a rod photoreceptor pigment protein. Subsequently, mutations in this gene have been implicated as responsible for some forms of adRP 5-9. Another adRP gene has been mapped to chromosome 8p (ref. 10). A third adRP gene in a large Irish pedigree has been mapped to chromosome 6p (refs 11, 12), showing tight linkage with the gene for peripherin 13,14, a photoreceptor cell-specific glycoprotein, which is thus a strong candidate for the defective gene. We have now identified a three-base-pair deletion which results in the loss of one of a pair of highly conserved cysteine residues in the predicted third transmembrane domain of peripherin. This deletion segregates with the disease phenotype but is not present in unaffected controls, and suggests that mutant peripherin gives rise to retinitis pigmentosa.