Mice deficient in the NF-κB transcription factor family member c-Rel, which is known to regulate the expression of mitochondrial uncoupling protein 4 (UCP4) [131], a proton transporter localized on the inner membrane, develop an age-dependent levodopa-responsive parkinsonism with nigral α-synuclein aggregation and neuron degeneration, as well as striatal synaptic dysfunction [132]. The gene discussed is SLC25A27; the disease is Parkinsonism.