However, the Prph2R172W model is associated with early-onset cone degeneration with rod defects being less severe until later, and it was not clear whether eliminating Rtbdn would also have an effect on rod-dominant diseases, such as retinitis pigmentosa (RP) or mixed cone-rod dystrophies and pattern dystrophies. The gene discussed is RTBDN; the disease is retinitis pigmentosa 1.