Boutoual et al. (2018)revealed that the HIF–PPARγ–UCP2–AMPK axis played an important role in the metabolic reprogramming of the MTO1- and GTPBP3-defective cells, and these defects caused infantile hypertrophic cardiomyopathy with lactic acidosis. Interestingly, in breast cancer, HIF-1α is activated by PPAR-γ to induct autophagy, and HIF-1α knockout blocks PPAR-γ activation–induced autophagosome formation (Zhou et al., 2009). Here, MTO1 is linked to lactic acidosis.