Abstract
Hyperornithinemia is a finding in GA (B6-responsive and non-responsive variants) due to ornithine transaminase (OKT) deficiency and in HHH, in which all known enzymes in ornithine metabolism are normal and the primary metabolic defect is not defined. Fibroblasts from GA and HHH when incubated for 614 hrs. with 14C-ornithine and 3H−leucine failed to incorporate 14C into protein, resulting in low 14C/3H ratios (0.006-0.017; control 0.239±.046). The GA B6-responsive variant was able to incorporate 14C into protein at a reduced rate (ratio of 0.097). Following PEG 1000 mediated cell fusion 14C/3H incorporation was measured in heterokaryons. Each of 3 GA B6-nonresponsive lines was hybridized with the GA B6-responsive line. Lines of both GA variants were fused with 2 HHH lines. No complementation was observed between any of the GA B6-nonresponsive lines and the GA B6-responsive line, but both GA variant lines complemented the HHH lines. These data suggest that the B6-responsive and -nonresponsive variants of GA are due to non-complementing mutations in the same structural gene. The complementation between GA cells and HHH cells supports other biochemical and clinical data that the mechanisms of hyperornithinemia are distinct in these two disorders.
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Shih, V., Mandell, R., Jacoby, L. et al. 762 GENETIC COMPLEMENTATION ANALYSIS IN FIBROBLASTS FROM GYRATE ATROPHY (GA) AND THE SYNDROME OF HYPERORNITHINEMIA, HYPERAMMONEMIA AND HOMOCITRULLINURIA (HHH). Pediatr Res 15 (Suppl 4), 569 (1981). https://doi.org/10.1203/00006450-198104001-00786
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DOI: https://doi.org/10.1203/00006450-198104001-00786
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