Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Kearns-Sayre syndrome is a mitochondrial genetic disorder characterized by ataxia and external ophthalmoplegia. Other features include proximal myopathy, cardiac conduction defects, sensorineural hearing loss, retinitis pigmentosa, and multiple endocrinopathies. MRI demonstrates high signal in the globus pallidi on T2/FLAIR (A, white arrows) and corticospinal tracts (A, yellow arrows). Symmetrical involvement of subcortical white matter (A and B, red arrows) with relative sparing of periventricular white matter is a feature. The cerebellum, corticospinal tracts (C, arrow), and brain stem can be involved early. Cerebral and cerebellar atrophy is common. CT usually demonstrates subcortical and basal ganglia calcification (not shown here).