PPT1 and infantile neuronal ceroid lipofuscinosis: Infantile neuronal ceroid lipofuscinosis (INCL or CLN1 disease) is a severe neurological disorder caused by LOF mutations in the PPT1 gene that presents in the first 6–12 months of life and is characterized by rapid developmental regression, blindness and seizures, with continual deterioration until death in early childhood (Nita et al., 2016).