Neuronal ceroid lipofuscinosis type 1 (CLN1), also known as infantile neuronal ceroid lipofuscinosis (INCL), is a rare (1 in 100,000 births), but one of the most lethal, inherited neurodegenerative lysosomal storage disorders caused by mutations in the PPT1 gene resulting in PPT1 deficiency. This evidence concerns the gene PPT1 and neuronal ceroid lipofuscinosis 1.