HTT and Huntington disease: HD is a neurodegenerative genetic disorder that is primarily caused by a mutation in the huntingtin gene and affects the function of the central nervous system (CNS), and a single-cell dissection of the human brain vasculature revealed that during the progression of HD, the innate immune signaling was activated in the vascular and glial cell types and the endothelial tight junction protein expression was reduced, which impaired the integrity of the BBB (Garcia et al., 2022).