In addition, TPP1 activity, which is known to be completely abrogated in LINCL patients [2], could not be detected, as expected, in extracts from CLN2 fibroblasts previously incubated under high (H, KH) and low (L, KH supplemented with insulin and amino acids) proteolysis conditions and, thus, of high and low macroautophagic activity. This evidence concerns the gene INS and late infantile neuronal ceroid lipofuscinosis.