Because humans with MGME1 mutations typically develop late-onset-mitochondrial disease [9,12], we decided to characterize ageing cohorts of Mgme1 knockout mice by an extensive phenotypic analysis, including clinical chemistry (haematology, metabolism and organ function), energy metabolism (indirect calorimetry, body composition), evaluation of different organ systems, immune system characterization and pathological assessment of tissue changes. The gene discussed is MGME1; the disease is mitochondrial disease.