Knockout of the Aipl1 gene results in post-transcriptional reduction of all the three subunits of the cGMP-PDE holoenzyme (α, ß and γ); in this model the retinal degeneration is even faster than in the rd1, resulting in a complete loss of photoreceptors by 3 weeks of age, indicating that the treatment window should be even smaller in the Aipl1−/− mouse compared with rd1 mice16, 23. The gene discussed is PDE6B; the disease is retinal degeneration.