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Megaloblastic anemia 1 (MGA1)

Genes

Summary

Megaloblastic anemia 1, also known as Imerslund-Grasbeck syndrome is a rare recessively inherited macrocytic anemia due to defective or absent absorption of vitamin B12 (cobalamin). Initially, the Finnish cases were found to have mutations in CUBN, whereas the Norwegian cases were found to have mutations in AMN. However, Finnish MGA1 mutation in also AMN gene has recently been reported. CUBN and AMN both encode subunits of vitamin B12-gastric intrinsic factor receptor. The anemia of MGA1, usually detected during early childhood, is macrocytic, and vitamin B12 level in blood is low. Anemia responds completely for intramuscular administration of vitamin B12. Anemic patients may also have neurological symptoms. Mild proteinuria is a frequent finding in MGA1, which is in line with observations of high expression of cubilin in renal tubular cells. Hematological studies together with B12 absorption assay provide clinical diagnosis of MGA1, which today can be confirmed by mutation detection of CUBN and AMN genes.

Links

UMLS Concept names

  • C1306856 IGS
  • C1306856 MEGALOBLASTIC ANEMIA 1
  • C1306856 PERNICIOUS ANEMIA, JUVENILE, DUE TO SELECTIVE INTESTINAL MALABSORPTION OF VITAMIN B12, WITH PROTEINURIA
  • C1306856 MGA1
  • C1306856 ENTEROCYTE COBALAMIN MALABSORPTION
  • C1306856 ENTEROCYTE INTRINSIC FACTOR RECEPTOR, DEFECT OF
  • C1306856 IMERSLUND-GRASBECK SYNDROME

Selected publications

  • Nat Genet. 1999 Mar;21(3):309-13. Mutations in CUBN, encoding the intrinsic factor-vitamin B12 receptor, cubilin, cause hereditary megaloblastic anaemia 1. Aminoff M1, Carter JE, Chadwick RB, Johnson C, Gräsbeck R, Abdelaal MA, Broch H, Jenner LB, Verroust PJ, Moestrup SK, de la Chapelle A, Krahe R. PMID: 10080186 (Pubmed)
  • Nat Genet. 2003 Mar;33(3):426-9. Epub 2003 Feb 18. Amnionless, essential for mouse gastrulation, is mutated in recessive hereditary megaloblastic anemia. Tanner SM1, Aminoff M, Wright FA, Liyanarachchi S, Kuronen M, Saarinen A, Massika O, Mandel H, Broch H, de la Chapelle A. PMID: 12590260 (Pubmed)