<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by infantile neuronal ceroid lipofuscinosis ? [/INST] The incidence of infantile NCL is unknown. Collectively, all forms of NCL affect an estimated 1 in 100,000 individuals worldwide. NCLs are more common in Finland, where approximately 1 in 12,500 individuals are affected. </s>