MITOCHONDRIAL ENCEPHALOPATHY WITH MULTIPLE MITOCHONDRIAL-DNA DELETIONS - A REPORT OF 2 FAMILIES AND 2 SPORADIC CASES WITH UNUSUAL CLINICAL AND NEUROPATHOLOGICAL FEATURES

A mitochondrial myopathy associated with multiple deletions of mitocho ndrial DNA has been identified in pedigrees showing an autosomal domin ant mode of inheritance. We report the first two British kindreds with this disorder, and two sporadic cases. The families exhibited some un usual clinical features, including pigmentary retinopathy and tremor; the latter was levodopa-responsive and associated with rigidity and mi crographia in one family. Members of one pedigree and both sporadic pa tients had a peripheral neuropathy and nerve biopsy showed marked axon al degeneration. Post-mortem examination of one patient without parkin sonism showed severe neuronal loss in the substantia nigra.