Methylmalonic aciduria (MMA) is an autosomal recessive disorder of cobalamin (cbl) metabolism. Cobalamin C (cblC) disease is the most common type of MMA and is characteristically concurrent with homocystinemia (HCY) due to impaired synthesis of two active forms of cbl, namely adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl). The estimated worldwide incidence of MMA ranges between 1:48,000...

We have read with interest Maktouf et al.’s letter about the etiological role of deficiencies of cobalamin or folate in megaloblastic anemia. In this large prospective series, they investigated 478 patients with megaloblastic changes in bone marrow smears and reported the demographic, biological and clinical findings in cobalamin-deficient patients and patients with pernicious anemia. Out of 43...

BACKGROUND Early detection of cobalamin deficiency is clinically important, and there is evidence that such deficiency occurs more frequently than previously anticipated. However, serum cobalamin and other commonly used tests have limited ability to diagnose a deficiency state. METHODS We investigated the ability of hematological variables, serum cobalamin, plasma total homocysteine (tHcy), s...

To determine whether the increased prevalence of low serum cobalamin concentrations in elderly people represents true deficiency, serum concentrations of cobalamin and folate and of metabolites that are sensitive indicators of cobalamin deficiency were measured in 548 surviving members of the original Framingham Study cohort. Serum cobalamin concentrations < 258 pmol/L were found in 222 subject...

BACKGROUND During infancy, minor developmental delays and gastrointestinal complaints are common, as is a biochemical profile indicative of impaired cobalamin status. OBJECTIVE We investigated whether cobalamin supplementation can improve development or symptoms in infants with biochemical signs of impaired cobalamin function and developmental delay or feeding difficulties. DESIGN Infants <...

BACKGROUND The gold standard for cobalamin deficiency treatment is administration of cobalamin by intramuscular injection. The injection is painful and inconvenient, particularly for elderly persons. Cobalamin might also be administered intranasally. Previous studies do not provide insight into the pharmacokinetics of intranasal cobalamin administration in comparison with cobalamin injection. ...

The present study sought to determine the spectrum of diseases associated with subnormal concentrations of serum cobalamin in cats undergoing investigation of suspected gastrointestinal problems. The solid-phase boil radioassay (RA) for cobalamin employed in the present study was immunologically specific, precise, and accurate, with a sensitivity of 15 pg/mL. The RA yielded results that strongl...