More recently, using healthy untransfected neuronal cultures including neuroblastoma Neuro2a (N2a) cells and human cortical induced pluripotent stem cells (iPSCs), less than 1% of extracellular tau was found in exosomes while the majority of tau was found to be free-floating consisting of truncated c-terminal fragments of tau. The gene discussed is MAPT; the disease is neuroblastoma.