A mutation in a patient with mitochondrial DNA depletion and congenital anomalies.

Defects in two subunits of succinate-CoA ligase encoded by the genes and have been identified in mitochondrial DNA (mtDNA) depletion syndromes. Patients generally present with encephalomyopathy and mild methylmalonic acidemia (MMA), however mutations in normally appear to result in a more severe clinical phenotype. In this report, we describe a patient with fatal infantile lactic acidosis and multiple congenital anomalies (MCAs) including renal and cardiac defects. Molecular studies showed a defective electron transport chain (ETC), mtDNA depletion, and a novel homozygous mutation in the gene. Although our patient's clinical biochemical phenotype is consistent with a mutation, it is unclear whether the MCAs observed in our patient are a result of the mutation or alterations in a second gene. An increasing number of reports have described MCAs associated with mitochondrial disorders and specifically. Additional studies such as whole exome sequencing will further define whether additional genes are responsible for the observed MCAs.