ABSTRACT
Neurodegeneration, ataxia, pigmentary retinopathy, Leigh syndrome, neurogenic muscle weakness, peripheral neuropathy, and point mutation in the mitochondrial gene for subunit 6 of mitochondrial adenosine triphosphatase, usually a T to G8993, or a T to C8993 transversion. The heterogeneity of Leigh syndrome is pointed up by the fact that the 12 patients of F. M. Santorelli et al. were found in the study of 50 patients with typical Leigh syndrome. Patients with infantile encephalopathy and Leigh syndrome have tended to have over 95 percent of mutant mitochondrial DNA. The syndrome in these patients is characterized by developmental delay, some after a period of normal development, and hypotonia followed by psychomotor regression; some have had ataxia or dystonic posturing. A maternal aunt and uncle had died of Leigh syndrome. Another maternal uncle was normal until 12 years of age, when he developed a bout of weakness and ataxia from which he recovered.
