These findings are in contrast to previous works showing that TET1-CD fused to SpdCas9 and/or recruited by the gRNA-MS2-MCP system enabled re-expression of TSGs, such as BRCA1 in breast and cervical cell lines [65]; SARI in colon cancer [66]; RANKL [67] in neuroblastoma; several hypermethylated genes in lung adenocarcinoma, via the SunTag platform recruiting TET1-CD and VP64 [68]; and FMR1 in induced pluripotent stem cells derived from fragile X syndrome patients by SpdCas9-TET1-CD encoded in a lentiviral vector [69]. The gene discussed is TET1; the disease is fragile X syndrome.