Therefore, growing PRKN-PD fibroblasts in a glucose-free medium such as galactose, which has been previously used for the diagnosis of primary mitochondrial diseases [35,36], may provide a closer approach to the more oxidative metabolism and the potential associated mitochondrial function alterations present in the DAn of PRKN-PD patients. The gene discussed is PRKN; the disease is inborn mitochondrial metabolism disorder.