IDH1 and astrocytoma (excluding glioblastoma): TD2.2 could be fused to RNA- or DNA-binding domains for delivery of beneficial transcripts to glia, and may also represent a method for treatment of other glial cell-related diseases, for example, genetic correction of isocitrate dehydrogenase 1 (NADP+), soluble (IDH1) gene mutations, common in astrocytomas and oligodendroglial tumours, with functional (i.e. non-mutant) enzyme [40].