Photosensitivity is very common in young PME patients (up to 90%), and many genes have been reported to be associated with photosensitivity, including TPP1, KCTD7, BSCL2, KCNC1, GBA, SCARB2, ASAH1, GOSR2, ATN1, CLN6, and mt-DNA (3–5, 15–17). This evidence concerns the gene TPP1 and progressive myoclonus epilepsy.