The typical clinical presentation of SCO2 mutations is severe, rapidly progressive hypertrophic cardiomyopathy that presents in the neonatal period and is often associated with respiratory difficulties, metabolic acidosis, and hypotonia.
We report two novel pathogenic SURF1 mutations in a patient with Leigh syndrome and one novel SCO2 mutation in a patient with hypertrophic cardiomyopathy.
Mutations have, however, been identified in several COX assembly factors: SURF1 (Leigh Syndrome), SCO2 (hypertrophic cardiomyopathy), SCO1 (hepatic failure, ketoacidotic coma), and COX10 (encephalopathy, tubulopathy).
The clinical spectrum of SCO2 deficiency includes the delayed development of hypertrophic obstructive cardiomyopathy and severe neurogenic muscular atrophy.
Recently, we and others have shown that mutations in SCO2 are associated with a lethal infantile hypertrophic cardiomyopathy (HCMP) with COX-deficiency.
All of the patients with mutations in SURF-1 had Leigh syndrome, whereas the 3 patients with SCO2 mutations had a combination of encephalopathy and hypertrophic cardiomyopathy, and the neuropathology did not show the typical features of Leigh syndrome.