hydroxocobalamin and Retinal-Degeneration

Topics: Amino Acid Metabolism, Inborn Errors; Betaine; Cobamides; Female; Homocysteine; Homocystinuria; Humans; Hydroxocobalamin; Infant; Macula Lutea; Methionine; Methylmalonic Acid; Retina; Retinal Degeneration; Vision, Ocular; Visual Acuity; Vitamin B 12 Deficiency

A 33-month-old boy with an inborn error of vitamin B12 metabolism characterized by methylmalonic aciduria, homocystinuria, cystathioninuria , and hypomethioninemia had poor vision and a progressive retinal pigmentary degeneration. The child had early growth retardation with microcephaly, developmental delay, and a megaloblastic anemia. The retinal lesions were first noted when he was 1 year of age and, by ophthalmoscopy and by electroretinographic testing, have progressed. Treatment with hydroxocobalamin and L-methionine improved the anemia and the biochemical abnormalities but apparently did not halt the retinal degeneration. We believe the retinopathy is a feature of this disease, particularly in patients with infantile involvement. The retinal lesion may be caused by an unidentified abnormality of sulfur amino acid metabolism.

Topics: Amino Acid Metabolism, Inborn Errors; Amino Acids, Sulfur; Child, Preschool; Cystathionine; Growth Disorders; Homocystinuria; Humans; Hydroxocobalamin; Male; Malonates; Methionine; Methylmalonic Acid; Retinal Degeneration; Vitamin B 12