Genetic mapping demonstrates that the alpha-subunit of retinal cGMP-phosphodiesterase is not the site of the rd mutation.

In the inherited degenerative retinal disease of the rd mouse, rod cGMP levels rise above normal due to depressed cGMP-phosphodiesterase (cGMP-PDE) function a few days before degeneration begins. The subnormal activity of the cGMP-PDE may be due to a lesion in the enzyme itself, or in any of several proteins that regulate it. We have used a bovine cDNA for the alpha-subunit of cGMP-PDE to map its gene Pdea to mouse chromosome 18 at a distance of 21 centimorgans (cM) from the Mbp locus. Since the locus of the rd mutation is on mouse chromosome 5, a defect in the Pdea gene is ruled out as the cause of this inherited retinal degeneration.