Succinate Coenzyme A Ligase, GDP Forming, Alpha Subunit (SUCLG1)

SUCLG1 encodes the alpha subunit of the heterodimeric enzyme succinate coenzyme A ligase. This enzyme is targeted to the mitochondria and catalyzes the conversion of succinyl CoA and ADP or GDP to succinate and ATP or GTP. Mutations in this gene are the cause of the metabolic disorder fatal infantile lactic acidosis and mitochondrial DNA depletion.

Despite the similar findings--i.e., a combined oxidative phosphorylation deficiency and mtDNA depletion--patients with SUCLA2 and SUCLG1 mutations differ markedly in their clinical presentations. The patients with SUCLG1 mutations had an exceedingly severe phenotype, whereas the phenotypes of patients with SUCLA2 were milder.