According to Cooper et al., in a rat model ofParkinson’s disease, neural stem cells in theSVZ exposed to TGF-α underwent massive proliferation,migration and differentiation (13).TGF-α blinding to the EGF receptor (EGFR),a tyrosine kinase receptor encoded by ErbBgene, is expressed in the proliferating cells ofthe developing rat (21). The gene discussed is NTRK1; the disease is glycogen storage disease VI.