TPP1 and neuronal ceroid lipofuscinosis: Infantile forms are clinically characterized by epileptic seizures, loss of speech, vision, cognitive and motor skills, and early death.1Currently, 14 NCL types have been identified:CLN1,CLN2,CLN3,CLN4,CLN5,CLN6,CLN7,CLN8,CLN9,CLN10,CLN11,CLN12,CLN13, andCLN14; however, to date, neuronal ceroid lipofuscinosis type 2 (CLN2) is the only NCL with an approved targeted therapy.2