CLN6 and Onset: Guerreiro et al., documented CLN6 mutation presenting as late infantile form in two Pakistani families.16 CLN2, CLN5 and CLN8 gene mutations presented as late infantile but CLN3 presented as a juvenile-onset disease characterized by rapid progressive loss of vision as the first presenting symptom.13,14 Also Sher M et al., documented CLN3 presenting as a juvenile form in large Pakistani families.