According to the age of onset, CLNs are classified into six subtypes, including a congenital form (CLN10, MIM610127), an infantile form (CLN1, Santavuori-Haltia disease; MIM256730), a late infantile form (CLN2, Jansky Bielschowsky disease; MIM204500), variable late infantile forms (CLN5, MIM256731; CLN6, MIM601780; CLN7, MIM610951 and CLN8, MIM600143), a juvenile form (CLN3; Spiel-Meyer-Vogt-Sjogren disease; MIM304200), and an adult form (CLN4; Kufs disease; MIM204300) [7,8,9,10,11,12]. Here, TPP1 is linked to infantile neuronal ceroid lipofuscinosis.