PPT1 and inherited retinal dystrophy: While the relevance of the marked upregulation of lysosomal protein biosynthesis for the progression of the retinal dystrophies is unknown, it might serve as a useful pathogenic marker for studies aimed at correcting lysosomal dysfunction in the Ppt1 ko retina as we have recently demonstrated in Ctsd ko mice after intravitreal injections of human pro-CTSD62.