UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

Imerslund-Grasbeck Syndrome (IGS)


Imerslund-Gräsbeck syndrome (IGS) is a disorder found in Beagles and Border Collies where dietary cobalamin (vitamin B12) is unable to be absorbed through the gut. Both breeds have independent mutations in the cubulin (CUBN) gene. The disease has an autosomal recessive mode of inheritance with both sexes being equally affected. Owners of IGS affected dogs often note a lack of appetite, failure to gain weight, lethargy and malaise that intensifies after eating. Clinically, anemia and excess urine protein is observed. Without chronic treatment, permanent brain and nervous system damage can occur. Dogs with one normal and one mutated IGS gene, carriers, are unaffected but breeding two carriers together would be predicted to produce 25% affected offspring and 50% carriers.

The VGL offers a test for inherited IGS in Beagles and Border Collies to assist owners and breeders in identifying affected and carrier dogs. The test uses DNA collected from buccal (cheek) swabs, thus avoiding blood sample collection. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing affected dogs.

ORDER TEST KITS - Allow 2-6 business days for results.

Results reported as:

N/N No copies of the IGS mutation; dog is normal
N/IGS 1 copy of the IGS mutation; dog is a carrier
IGS/IGS 2 copies of the IGS mutation; dog is affected


Fyfe JC, Hemker SL, Venta PJ, Fitzgerald CA, Outerbridge CA, Myers SL, Giger U. (2013) An exon 53 frameshift mutation in CUBN abrogates cubam function and causes Imerslund-Gräsbeck syndrome in dogs. Mol Genet Metab. 109(4):390-396.

Drögemüller M, Jagannathan V, Howard J, Bruggmann R, Drögemüller C, Ruetten M, Leeb T, Kook PH. (2013) A frameshift mutation in the cubilin gene (CUBN) in Beagles with Imerslund-Gräsbeck syndrome (selective cobalamin malabsorption). Anim Genet. Oct 27, DOI:10.1111/age.12094.

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL