NDUFB9 and inborn mitochondrial metabolism disorder: Many mitochondrial disease-related altered proteins also formed part of the energy network (DLD, NDUFA4, NDUFB5, NDUFB6, NDUFB9, NDUFS1, NDUFA12 and UQCRB) and belong to respiratory electron transport with the exception of DLD, which belongs to the TCA cycle (Figure 3B).