| Characterized by early neonatal onset of hypotonia, hypertrophic cardiomyopathy and apneic spells within hours after birth accompanied by lactic acidosis, hyperammonemia and 3-methylglutaconic aciduria. Most patients who survive the neonatal period have mild cranio-facial dysmorphism with low set ears, prominent nasal bridge and retrognathia, persisting muscular hypotonia and moderate psychomotor developmental delay. The result of an isolated decrease in the tissue content and activity of mitochondrial FoF1 ATP synthase caused by depressed biosynthesis of the enzyme. This enzyme defect is present in all tissues and is due to autosomal recessive mutations in the TMEM70 gene (8q21.11), encoding ancillary factor of ATP synthase biogenesis. |
