TMPRSS11D and Huntington disease: Dysregulated expression of peroxisome proliferator-activated receptor γ (PPARγ) co-activator 1α (PGC-1α), a regulator of mitochondrial biogenesis and oxidative stress [23,24]; CREB binding protein (CBP), a histone acetyltransferase (HAT) transcriptional co-activator [25,26] and brain-derived neurotrophic factor (BDNF) are all important for the maintenance and survival of neurons [27,28] and are all dysregulated in HD.