Research has demonstrated a significant downregulation of FKBP51 expression across multiple Huntington’s disease (HD) models, including the striatum and cortex of R6/2 and zQ175 transgenic mice, as well as in human induced pluripotent stem cell (iPSC)-derived HD neural stem cells (NSCs) and medium spiny neurons (MSNs) (Bailus et al., 2021). This evidence concerns the gene FKBP4 and Huntington disease.