It has been suggested that the selective loss of these neurons in HD may be associated with altered synaptic transmission (Klapstein et al., 2001; Cepeda et al., 2003; Li et al., 2003; Smith et al., 2005; Raymond et al., 2011; Tyebji and Hannan, 2017; Virlogeux et al., 2018), reduced support of brain-derived neurotrophic factor (BDNF; Zuccato and Cattaneo, 2009, 2014; Park, 2018; Yu et al., 2018), mitochondrial dysfunction (Carmo et al., 2018; Franco-Iborra et al., 2018), and altered Ca2+ regulation (Bezprozvanny, 2009; Miller and Bezprozvanny, 2010; Raymond, 2017). Here, BDNF is linked to Huntington disease.