Rare genetic disorder affecting mitochondrial metabolism of
ornithine. It is characterized by the presence of gyrate atrophy of the
retina leading to night blindness that begins in late childhood, accompanied
by sharply demarcated circular areas of chorioretinal atrophy. The areas of
atrophy enlarge during the second and third decades. Posterior subcapsular
cataracts have been associated by the end of the second decade. Computed
tomography and magnetic resonance imaging (MRI) studies demonstrated the presence of type II muscle fiber
changes in large muscle groups because of hyperornithinemia-induced
deficiency of high-energy creatine phosphate. Brain MRI revealed
degenerative lesions in the white matter in 50% of the gyrate atrophy
patients, and 70% present premature atrophic changes. Early degenerative,
atrophic brain changes and abnormal EEG are features of gyrate atrophy, in
addition to the well-characterized eye and muscle manifestations.