SPG7 and hereditary spastic paraplegia: Treatment of HSP-SPG7 patient neurons with low nano molar concentrations of mPTP targeting drug Bz-423, shown to rescue the defect of swollen mitochondrial and motor impairment in paraplegin-deficient HSP-SPG7 mice model (Giorgio et al., 2013; Sambri et al., 2020), also restored the defect of increased mitochondrial size in our patient neurons back to control neuron levels, further indicating that the increased mitochondrial size and reduced membrane potential in HSP-SPG7 patient neurons was a consequence of mPTP dysfunction.