For example, it is known that Parkinson’s disease is etiologically heterogeneous; thus, mutations in the PINK1 gene (a known cause of Parkinson’s disease) affect the ability of mitochondria to utilise CoQ10 in the energy generation process, so it follows that supplementing with CoQ10 would not benefit this type of Parkinson’s disease patients. The gene discussed is PINK1; the disease is Parkinson disease.