Evaluation of the gene encoding the gamma subunit of rod phosphodiesterase in retinitis pigmentosa.

Purpose: To determine whether defects in the gene encoding the gamma subunit of rod cyclic guanosine monophosphate-phosphodiesterase (PDE-g) cause some form of hereditary retinal degeneration or dysfunction.
Methods: A restriction map, an intron/exon map, and a partial sequence of the human genomic locus corresponding to this gene were ascertained. Based on this information, the single-strand conformation polymorphism technique (SSCP) was used to screen the coding region as well as most splice donor and acceptor sites for mutations in a total of 704 unrelated patients with retinitis pigmentosa, Usher's syndrome type I or type II, Leber's congenital amaurosis, the Laurence-Moon-Bardet-Biedl syndrome, or other hereditary retinal disease.
Results: Two frequent polymorphisms were found, as well as three rare sequence variations, none of which correlated with any phenotype examined.
Conclusions: In view of these negative results and those of a previously published negative Southern blot analysis of an overlapping set of patients, it is unlikely that mutations in the PDE-g gene are a common cause of any of the forms of retinal degeneration or dysfunction so far examined.