Retinal degeneration in vitamin B12 disorder associated with methylmalonic aciduria and sulfur amino acid abnormalities.
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.
D000592:Amino Acid Metabolism, Inborn Errors / Q000150:complications*; D000603:Amino Acids, Sulfur / Q000378:metabolism*; D002675:Child, Preschool; D003540:Cystathionine / Q000652:urine; D006130:Growth Disorders / Q000150:complications; D006712:Homocystinuria / Q000150:complications; D006801:Humans; D006879:Hydroxocobalamin / Q000627:therapeutic use; D008297:Male; D008314:Malonates / Q000652:urine*; D008715:Methionine / Q000097:blood / Q000627:therapeutic use; D008764:Methylmalonic Acid / Q000652:urine*; D012162:Retinal Degeneration / Q000209:etiology*; D014805:Vitamin B 12 / Q000378:metabolism*
D000603:Amino Acids, Sulfur; D008314:Malonates; D003540:Cystathionine; D008764:Methylmalonic Acid; D008715:Methionine; D014805:Vitamin B 12; D006879:Hydroxocobalamin