In mouse models of SBMA, decreases in the mRNA levels of vascular endothelial growth factor (VEGF) (Sopher et al., 2004), skeletal muscle chloride channel 1 (CLCN1), skeletal muscle sodium channel α-subunit, neurotrophin-4 (NT-4), glial cell line-derived neurotrophic factor (GDNF) (Yu et al., 2006a), dynactin 1 (Katsuno et al., 2006), genes related to mitochondrial function (Ranganathan et al., 2009), and TGF-β receptor type II (TGF-βRII) (Katsuno et al., 2010a) have been described. The gene discussed is GDNF; the disease is Kennedy disease.