Patients P04 and P05 presented with sensory ataxia neuropathy dysarthria and ophthalmoplegia (SANDO) phenotype associated with recessive mutations in POLG. Patient P06 had a neonatal encephalopathy with lactic acidosis and mild methylmalonic aciduria linked to mutations in the SUCLG1 gene. The gene discussed is POLG; the disease is ophthalmoplegia.