UQCRC2 mutation in a patient with mitochondrial complex III deficiency causing recurrent liver failure, lactic acidosis and hypoglycemia.

An isolated mitochondrial complex III (CIII) defect constitutes a rare cause of mitochondrial disorder. Here we present the second case involving UQCRC2 gene, which encodes core protein 2, one of the 11 structural subunits of CIII. The patient has the same mutation (c.547C>T; p.Arg183Trp) as the first case and presented with neonatal lactic acidosis, hypoglycemia and severe episodes of liver failure. Our study expands the few reported cases of CIII deficiency of nuclear origin.