NEUROD1 and juvenile Huntington disease: In addition to overexpressing the transcription factor NeuroD1 in astrocytes, previous studies demonstrated that down-regulation of polypyrimidine tract binding protein 1 (PTBP1) expression in astrocytes can also induce conversion into neurons in situ. At present, neurogenesis gene therapy based on PTBP1 knockdown has achieved remarkable results and has been applied to various neurological disease models, such as stroke, Huntington’s disease, PD, and retinal damage (Qian et al., 2020; Wu et al., 2020; Zhou et al., 2020).