BDNF and Huntington disease: The link between FTY720, increased BDNF levels and neuroprotection has been well described in cell cultured and animal models of Rett syndrome (Deogracias et al., 2012), HD (Miguez et al., 2015), AD (Doi et al., 2013; Fukumoto et al., 2014) and PD (Giasson et al., 2002).