Focusing on a specific pathway through the use of a comprehensive untargeted and targeted lipidomics, Ruiz and colleagues revealed the characteristic metabolic perturbations in a homogeneous group of patients with mitochondrial diseases (Leigh syndrome French-Canadian variant [LSFC] associated with pathological variants in LRPPRC) and in mice harboring liver-specific inactivation of Lrpprc (H-Lrpprc−/−) [35]. The gene discussed is LRPPRC; the disease is inborn mitochondrial metabolism disorder.