A group of metabolic disorders, mainly in its infancy characterized by subacute onset hypotonia, psychomotor retardation, ataxia, weakness, vision loss, eye movement disorders, seizures, dysphagia, and lactic acidosis. Pathological features include spongy degeneration of the basal ganglia, Thalamus, brainstem and spinal cord neuropile. The patterns of inheritance of X-linked recessive autosomal recessive and mitochondrial. Leigh disease is associated with mutations in the genes coding for pyruvate dehydrogenase complex; cytochrome c oxidase; ATP synthase subunit 6; and the subunits of the mitochondrial complex I.