For instance, cytochrome c1 variants were described in two patients with early‐onset episodic acute metabolic ketoacidosis, lactic acidosis, hyperammonaemia and insulin‐responsive hyperglycaemia triggered by infection and febrile illness during childhood (Morison et al, 2008; Gaignard et al, 2013; De Rocco et al, 2014). The gene discussed is CYC1; the disease is lactic acidosis.