Mutations in mitochondrial transfer RNA modifying factors may also impair mitochondrial translation, as in myopathy, lactic acidosis and sideroblastic anaemia syndrome, a rare condition associated with mutations in the pseudouridylate synthase 1 gene (PUS1; NM_025215.5; GI:259155298; Bykhovskaya et al., 2004; Fernandez-Vizzara et al., 2007). This evidence concerns the gene PUS1 and lactic acidosis.