GDNF and nervous system disorder: Many genes are known to be neuroprotective, such as brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), which could be wildly applicable as gene therapy for many neurological disorders that occur due to a decrease in neuron health and increased cell death (Figure 3) (Laganiere et al., 2010; Nagahara and Tuszynski, 2011).