DHTKD1 and Friedreich ataxia: PDH-E1α−/− (Pyruvate dehydrogenase E1 subunit CRISPR knockout) HepG2 cells, which lack the E1α subunit of the pyruvate dehydrogenase complex, as well as GM04078 and GM01673 cells derived respectively from Friedreich Ataxia (FRDA) and Methylmalonic Aciduria (MMA) patients, were treated with the TAT-mPiC fusion protein.