GUCA1A and retinal degeneration: As deletion of GCAPs in mouse apparently has no detrimental morphological nor disease-causing defect, except for increased sensitivity and delayed recovery from the dark state (Mendez et al., 2001), we assumed that nonallele-specific shRNA knockdown of both wild-type and mutant GCAP1s may be a general therapeutic strategy to treat retinal degeneration in patients carrying GCAP1 mutations.