Methylmalonic Acid Excretion in Vitamin B₁₂ Deficiency

Abstract

methylmalonic acid was first isolated from pooled human urine in 1957 by Thomas and Stalder and convincing evidence has since been obtained to show that in man the isomerization of l‐methylmalonyl‐Co A to succinyl‐Co A is dependent on the B12 coenzyme dimethylbenzimidazolyl cobamide (White, 1962). Indeed, Cannata, Focesi, Mazumder, Warner and Ochoa (1965) showed recently that l‐methylmalonyl‐Co A mutase bears two molecules of cobamide coenzyme firmly attached to its molecule. In a series of 30 patients Cox and White (1962) detected excessive methylmalonic acid in the urine of all patients with serum vitamin B12 levels below 140 pg./ml., their lower limit of normal. Patients with normal serum B12 levels excreted up to 4 mg. of methylmalonic acid in 24 hours. Their series included six patients who were treated with intramuscular hydroxocobalamin (1000 μg.). In five of these, excretion fell to normal within 3 days, and on the fifth day after injection in the sixth patient. Barness, Young, Mellman, Khan and Williams (1963) reported one vitamin B12 deficient patient in whom the urinary excretion of methylmalonic acid reached 500 mg. in 24 hours. Recently Khan, Williams, Barness, Young, Shafer, Vivacqua and Beaupre (1965) have described seven out of nine patients with pernicious anaemia in whom methylmalonic acid excretion persisted for some months after the institution of B12 therapy. This occurred despite full clinical and haematological remissions and in four patients, normal serum vitamin B12 levels. The present study was undertaken to determine the value of urinary methylmalonic acid excretion as a screening test for vitamin B12 deficiency. The estimation of methylmalonic acid was carried out by a rapid thin layer chromatographic technique, suitable for routine laboratory use. Normal controls and patients suffering from general haematological and medical disorders were screened as well as patients suffering from megaloblastic anaemia. In several patients the excretion of methylmalonic acid was followed for a short period after B12 therapy.

Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

“…Previous investigators have shown that most patients with cobalamin (Cbl, vitamin B12)' deficiency have elevated levels of methylmalonic acid in their urine (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The origin of the methylmalonic acid has recently been elucidated (13) and is illustrated in Fig.…”

“…More rarely, diagnostic problems can also develop in patients with hematologic abnormalities, since serum Cbl levels may be normal in Cbl-deficient patients who have elevated levels ofCblbinding proteins (24). Additional diagnostic tests like urinary methylmalonic acid (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and the deoxyuridine suppression test (25,26) have not been widely used and, thus, a definite need exists for additional tests that could be used to evaluate patients for Cbl deficiency and to evaluate the sensitivity and specificity of the serum Cbl assay.…”

Vitamin E Deficiency in a Child with Intestinal Lymphangiectasia

“…The patient and control cases were loaded orally with 3g of valine14 and 24 hour-urine was collected and analyzed for methylmalonic acid by thin layer chromatography described by Bashir et al 15 The urinary excretion of methyl malonic acid was detectable in the present patient, but not in control cases. …”

Colorimetric Method for Determination of Urinary Methylmalonic Acid

“…Consequently, methylmalonic acid may be excreted in increased quantities in the urine in conditions associated with deficiency of the coenzyme, such as pernicious anaemia, dietary depletion of the vitamin, or a metabolic block in the synthesis of this derivative (Cox and White, 1962;Bashir et al, 1966;Rosenberg et al, 1968). This increase is accentuated by the oral administration of metabolic precursors of methylmalonic acid (Gompertz et al, 1967), and a number of studies have now demonstrated the usefulness of urinary methyl malonic acid determinations after valine loading in the diagnosis of cobalamin deficiency (Green and Pegrurn, 1968;Gutteridge and Wright, 1970;Dale, 1972).…”

“…Methylmalonic acid has been determined in urine by gas chromatography (Cox and White, 1962;Gornpertz et al, 1967), thin-layer chromatography Methods and materials (Bashir et al, 1966;Dreyfus and Dube, 1967;Gutteridge and Wright, 1970), and a colorimetric For the loading test, 10 g L-valine was administered method based on a coupling reaction with diazotised orally as a solution in approximately 250 ml orange p-nitroaniline (Giorgio and Plaut, ]965). The gas juice.…”