In this study, we expanded our GT approach through the following methods: (1) the use of the PP6D5 polymer as a non-viral vector for gene delivery in the context of TSD; (2) the evaluation of our CRISPR/nCas9-based approach in TSD relevant cells, such as astrocytoma and neuroblastoma cells; and (3) the co-transfection of HEXA and HEXB cDNAs, which was not evaluated in our previous study [13]. The gene discussed is HEXB; the disease is astrocytoma (excluding glioblastoma).