Other Pakistani families diagnosed with NCL carry private mutations in CLN5 (two mutations), CLN6 (one additional mutation to that reported here), CLN8 (three mutations) and CLN10 (two mutations), with none yet reported causing CLN1, CLN2, CLN3, CLN4 or CLN7 diseases.2, 8 Thus, it should be high priority to test for this CLN6 mutation in Pakistani families with any type of suspected NCL, but particularly with onset in late infancy, regardless of ultrastructural pathology of storage material, or even its apparent absence. The gene discussed is CTSD; the disease is neuronal ceroid lipofuscinosis.