Topics:
5-methyltetrahydrofolate-homocysteine s-methyltransferase, cobalamin, folic acid measurement, serum, genetic disorder, homocysteine, intrinsic factor-cobalamin receptor, megaloblastic anemia, methionine, methylenetetrahydrofolate reductase (nadph2), oxidoreductase

Erratum for Carmel R, Green R, Rosenblatt DS, Watkins D. Update on cobalamin, folate, and homocysteine. Hematology. 2003:62–81.

Page 74. Table 3. The final entry under the column heading cblE (1298A→ C) should be moved to the Methylenetetrahydrofolate Reductase (Severe Deficiency) column. The corrected table is below.

Table 3.

Selected features of inherited diseases discussed.

Imerslund-Gräsbeck 
 Syndrome (MGA1)cblEcblGMethylenetetrahydrofolate 
 Reductase (Severe Deficiency)
*http//www3.ncbi.nlm.nih.gov/Omim/ 
**postulated to be associated with common diseases 
OMIM No.* 261100 236270 250940 236250 
Gene(s) CUBM
 AMN MTRR MTR MTHFR 
Chromosome(s) 10p12.1
 14q32 5p15.2–p15.3 1q43 1p36.3 
Gene product(s) Cubilin
 Amnionless Methionine synthase
 reductase Methionine 
 synthase Methylenetetrahydrofolate
 reductase 
Serum cobalamin Low Normal Normal Normal 
Serum folate Normal Normal Normal Normal or Low 
Homocysteine elevation Not a major feature Yes Yes Yes 
Megaloblastic anemia Yes Yes Yes No 
Developmental delay No Yes Yes Yes 
Proteinuria Yes No No No 
Common polymorphisms**  66A→ G  2756A→ G 677C→ T
 1298A→ C 
Imerslund-Gräsbeck 
 Syndrome (MGA1)cblEcblGMethylenetetrahydrofolate 
 Reductase (Severe Deficiency)
*http//www3.ncbi.nlm.nih.gov/Omim/ 
**postulated to be associated with common diseases 
OMIM No.* 261100 236270 250940 236250 
Gene(s) CUBM
 AMN MTRR MTR MTHFR 
Chromosome(s) 10p12.1
 14q32 5p15.2–p15.3 1q43 1p36.3 
Gene product(s) Cubilin
 Amnionless Methionine synthase
 reductase Methionine 
 synthase Methylenetetrahydrofolate
 reductase 
Serum cobalamin Low Normal Normal Normal 
Serum folate Normal Normal Normal Normal or Low 
Homocysteine elevation Not a major feature Yes Yes Yes 
Megaloblastic anemia Yes Yes Yes No 
Developmental delay No Yes Yes Yes 
Proteinuria Yes No No No 
Common polymorphisms**  66A→ G  2756A→ G 677C→ T
 1298A→ C 
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© American Society of Hematology 2004
2004