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Failure of protein loading tests to identify heterozygosity for ornithine carbamoyltransferase deficiency
Author(s) -
Becroft D. M. O.,
Barry D. M. J.,
Webster D. R.,
Simmonds H. A.
Publication year - 1984
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/bf01805599
Subject(s) - ornithine carbamoyltransferase , loss of heterozygosity , human genetics , metabolic disease , genetics , heterozygote advantage , biology , medicine , ornithine , endocrinology , arginine , gene , amino acid , genotype , allele
Protein loading tests for the diagnosis of heterozygous ornithine carbamoyltransferase deficiency were performed on two occasions on an asymptomatic woman whose daughter and two infant sons died of the disease. Neither loading test produced the expected increases in urinary orotic acid excretion and studies of other pyrimidine and purine metabolites in urine and plasma did not suggest that these would provide better discrimination from non‐carriers. The results probably reflect an extensive inactivation of the mutant X chromosome in liver cells and reinforce the need for caution in interpreting negative test results.