Title: Serum methylmalonic acid before and after oral L-isoleucine loading in cobalamin-deficient patients
Abstract: Over a 1 1/2-year period, we measured concentrations of methylmalonic acid in serum before and after a standardized loading with oral L-isoleucine (100 mmol) in 13 patients admitted for evaluation of cobalamin deficiency. All patients had serum cobalamin values below 100 pmol l-1, but only 12 of the 13 patients were clinically confirmed cobalamin deficient. The clinically non-cobalamin-deficient patient had folate deficiency and was excluded. The serum methylmalonic acid concentrations before loading with isoleucine were above the upper reference limit (0.37 μmol l-1) in all the patients and L-isoleucine caused an increase in serum methylmalonic acid of more than 1.00 μmol l-1 in 11 of the 12 deficient patients. In the remaining patient the increase was 0.35 μmol l-1. The results show that a significant increase of an initially elevated serum methylmalonic acid concentration after isoleucine loading is a general finding in tissue cobalamin deficiency which strongly supports the diagnosis.
Publication Year: 1992
Publication Date: 1992-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 3
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