We present a boy of eight years of age with symptoms of
Kearns-Sayre syndrome (KSS) characterised by
ophthalmoparesis, palpebral ptosis,
mitochondrial myopathy, pigmentous
retinitis, associated to short stature, cerebellar signs, cardiac blockade, diabetes melitus, elevated
cerebrospinal fluid protein concentration, and focal
hand and
foot dystonia. The
skeletal muscle biopsy demonstrated ragged red fibers,
cytochrome C oxidase-negative and
succinate dehydrogenase-positive fibers. The
magnetic resonance imaging showed symmetrical signal alteration in tegmentum of
brain stem,
pallidum and
thalamus.
Mitochondrial DNA analysis from
skeletal muscle showed a deletion in heteroplasmic condition. The
association of
dystonia to KSS, confirmed by molecular
analysis, is first described in this case, and the importance of
oxidative phosphorylation defects in the physiopathogenesis of this type of
movement disorder is stressed.