MT-ND4 and metabolic syndrome: In our study, heteroplasmy is more pronounced in D-loop, ND5, ND4, and CYB, and it is associated with known mapped diseases such as cyclic vomiting syndrome; CPEO/Stroke/CM/breast, renal, and prostate cancer risk/altered brain pH/sCJD (Sporadic Creutzfeldt–Jakob disease), and LHON; PD protective factor/longevity/altered cell pH/metabolic syndrome/breast cancer risk/LS risk/ADHD/cognitive decline; and primary open-angle glaucoma (POAG) (Table S5).