However, as with any in vitro model of CNS disorders, NGN2 iNs have their limitations; specifically: forced differentiation may not fully recapitulate normal development as well as alternative differentiation methods and secondly, the observed expression, in some reports, of peripheral nervous system markers suggest a less well-defined cell identify in iNGN2 iNs [40, 41]. This evidence concerns the gene NEUROG2 and central nervous system disorder.