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The use of homocysteine and other metabolites in the specific diagnosis of vitamin B-12 deficiency.
J Nutr. 1996 04; 126(4 Suppl):1266S-72S.JN

Abstract

Vitamin B-12 (cobalamin) is a cofactor for only two enzymes, methionine synthase and L-methylmalonyl-CoA mutase. The serum vitamin B-12 concentration has been shown to have limitations in specificity and sensitivity in diagnosing vitamin B-12 deficiency and predicting response to therapy in subjects with clinical deficiency syndromes. Serum methylmalonic acid and/or total homocysteine concentrations have been shown to be elevated in almost every patient who has a clinical response to vitamin B-12. In elderly populations serum methylmalonic acid concentrations are elevated in the majority (60-66%) of subjects who have elevated total homocysteine concentrations, suggesting that vitamin B-12 deficiency (with or without associated folate deficiency) and/or chronic renal insufficiency may be the primary cause of most of the elevated total homocysteine concentrations in elderly populations. In such subjects vitamin B-12 and folate concentrations are both frequently in the low or low normal range, making differentiation of the clinical syndromes by use of serum vitamin concentrations problematic. Elevations of 2-methylcitric acid and cystathionine also result from vitamin B-12 deficiency. Serum N-methylglycine concentrations are normal in cobalamin deficiency but are increased in 40% of patients deficient in folate. In conclusion, elevations of methylmalonic acid and total homocysteine are very sensitive and specific in diagnosing vitamin B-12 deficiency and can be used to help differentiate vitamin B-12 deficiency from folate deficiency. Elevated total homocysteine concentrations that may have been attributed to folate deficiency in elderly subjects may in many instances be the result of vitamin B-12 deficiency even though serum vitamin B-12 concentrations are within normal limits.

Authors+Show Affiliations

University of Colorado Health Sciences Center, Denver, CO 80262, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

8642468

Citation

Stabler, S P., et al. "The Use of Homocysteine and Other Metabolites in the Specific Diagnosis of Vitamin B-12 Deficiency." The Journal of Nutrition, vol. 126, no. 4 Suppl, 1996, 1266S-72S.
Stabler SP, Lindenbaum J, Allen RH. The use of homocysteine and other metabolites in the specific diagnosis of vitamin B-12 deficiency. J Nutr. 1996;126(4 Suppl):1266S-72S.
Stabler, S. P., Lindenbaum, J., & Allen, R. H. (1996). The use of homocysteine and other metabolites in the specific diagnosis of vitamin B-12 deficiency. The Journal of Nutrition, 126(4 Suppl), 1266S-72S. https://doi.org/10.1093/jn/126.suppl_4.1266S
Stabler SP, Lindenbaum J, Allen RH. The Use of Homocysteine and Other Metabolites in the Specific Diagnosis of Vitamin B-12 Deficiency. J Nutr. 1996;126(4 Suppl):1266S-72S. PubMed PMID: 8642468.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The use of homocysteine and other metabolites in the specific diagnosis of vitamin B-12 deficiency. AU - Stabler,S P, AU - Lindenbaum,J, AU - Allen,R H, PY - 1996/4/1/pubmed PY - 1996/4/1/medline PY - 1996/4/1/entrez SP - 1266S EP - 72S JF - The Journal of nutrition JO - J Nutr VL - 126 IS - 4 Suppl N2 - Vitamin B-12 (cobalamin) is a cofactor for only two enzymes, methionine synthase and L-methylmalonyl-CoA mutase. The serum vitamin B-12 concentration has been shown to have limitations in specificity and sensitivity in diagnosing vitamin B-12 deficiency and predicting response to therapy in subjects with clinical deficiency syndromes. Serum methylmalonic acid and/or total homocysteine concentrations have been shown to be elevated in almost every patient who has a clinical response to vitamin B-12. In elderly populations serum methylmalonic acid concentrations are elevated in the majority (60-66%) of subjects who have elevated total homocysteine concentrations, suggesting that vitamin B-12 deficiency (with or without associated folate deficiency) and/or chronic renal insufficiency may be the primary cause of most of the elevated total homocysteine concentrations in elderly populations. In such subjects vitamin B-12 and folate concentrations are both frequently in the low or low normal range, making differentiation of the clinical syndromes by use of serum vitamin concentrations problematic. Elevations of 2-methylcitric acid and cystathionine also result from vitamin B-12 deficiency. Serum N-methylglycine concentrations are normal in cobalamin deficiency but are increased in 40% of patients deficient in folate. In conclusion, elevations of methylmalonic acid and total homocysteine are very sensitive and specific in diagnosing vitamin B-12 deficiency and can be used to help differentiate vitamin B-12 deficiency from folate deficiency. Elevated total homocysteine concentrations that may have been attributed to folate deficiency in elderly subjects may in many instances be the result of vitamin B-12 deficiency even though serum vitamin B-12 concentrations are within normal limits. SN - 0022-3166 UR - https://www.unboundmedicine.com/medline/citation/8642468/The_use_of_homocysteine_and_other_metabolites_in_the_specific_diagnosis_of_vitamin_B_12_deficiency_ L2 - https://academic.oup.com/jn/article-lookup/doi/10.1093/jn/126.suppl_4.1266S DB - PRIME DP - Unbound Medicine ER -