This corresponds to earlier findings in the Pde6b mutant rd1 and rd10 mouse models for RP,10,11 and is also seen in many other animal models for RP, carrying disease-causing mutations in a variety of different genes.11,27 As most of these models also display increased photoreceptor cGMP, it is possible that this rise is a component of the PARP activation. Here, PDE6B is linked to retinitis pigmentosa 1.