As shown in Fig. 1A and B, the levels of LONP1 were increased in all mutant cybrid lines with exception of m.Trp cells, expression of AFG3L2 was induced in all disease cell models except MELAS, and the levels of CLPP were increased in MELAS, m.Val and m.ND6 cells, whereas they were reduced in MERRF and m.Trp cells. The gene discussed is CLPP; the disease is MELAS.