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Genetic and Rare Diseases Information Center (GARD)

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Imerslund-Grasbeck syndrome

Other Names for this Disease
  • Defect of enterocyte intrinsic factor receptor
  • Enterocyte cobalamin malabsorption
  • Familial megaloblastic anemia
  • Gräsbeck-Imerslund disease
  • IGS
More Names
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Tests & Diagnosis

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How is Imerslund-Grasbeck syndrome diagnosed?

The diagnosis of Imerslund-Grasbeck syndrome (IGS) is made after a series of tests are performed. Cobalamin deficiency is typically detected first, followed by showing that cobalamin is poorly absorbed (the main cause of cobalamin deficiency). Other known causes of vitamin B12 malabsorption must then be ruled out. Lastly, it must be shown that after correcting the deficiency, the only nutrient to be poorly absorbed is vitamin B12. The diagnosis can also be confirmed by having genetic testing of the genes that are known to cause the condition. While the presence of proteinuria is strongly suggestive of IGS, not all affected individuals have proteinuria.[1]
Last updated: 1/6/2014

  1. Ralph Gräsbeck. Imerslund-Gräsbeck syndrome (selective vitamin B12 malabsorption with proteinuria). Orphanet J Rare Dis. May 19, 2006; 1(17):Accessed 1/6/2014.


  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.