Hyperornithinemia with gyrate atrophy of the choroid and retina: a disturbance in de novo formation of proline.

Two patients with hyperornithinemia and gyrate atrophy of the choroid and retina, the first report in Japan, were described. Serum ornithine was increased 10- to 15-fold and serum lysine was slightly decreased in the affected patients. Urinary excretion of ornithine was also markedly increased. There was no increase in serum proline after the oral loading of ornithine in the patients, whereas serum proline increased after the loading in normal controls. Ornithine-ketoacid transaminase (OKT) activity was markedly reduced in phytohemagglutinin transformed lymphocytes from the patients. In all of their parents and one of the siblings, OKT activity was found to be decreased to about half of the normal control values. These findings indicate that the pathway from ornithine to proline is a major route of ornithine catabolism in man. A possible pathogenesis of ocular disturbance in the patients with OKT deficiency was postulated.