NEUROG2 and autism: Another method utilizes Neurogenin-2 (NGN2) expression, which directly converts iPSCs to cerebral cortical layer 2/3 excitatory neurons14, and has been used to study disease-associated mutations in models of autism and schizophrenia24–26, tuberous sclerosis27, epileptic encephalopathy28, and neurodegenerative diseases29,30.