Imerslund-Gräsbeck Syndrome (IGS)

Quick Summary

Imerslund-Gräsbeck syndrome (IGS) is a disorder found in Beagles and Border Collies where vitamin B12 is unable to be absorbed through the gut.

Phenotype: 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.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal, IGS = Imerslund-Gräsbeck Syndrome

Breeds appropriate for testing: Beagle, Border Collie

Explanation of Results:

  • Dogs with N/N genotype will not have Imerslund-Gräsbeck syndrome and cannot transmit this Imerslund-Gräsbeck syndrome variant to their offspring.
  • Dogs with N/IGS genotype will not be affected by Imerslund-Gräsbeck syndrome, but are carriers. They will transmit this Imerslund-Gräsbeck syndrome variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% Imerslund-Gräsbeck syndrome-affected puppies.
  • Dogs with IGS/IGS genotype will have Imerslund-Gräsbeck syndrome

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Price

$50 one test per animal
$30 as additional test (same animal)

Panels Available
Additional Details

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. Symptoms of IGS  typically appear within 6-12 weeks after birth because stored vitamin B12 supplies are depleted.  Symptoms noted by owners include lethargy, failure to gain weight, malaise, and lack of appetite. Symptoms of lethargy and malaise seem to intensify after eating.  Clinically, anemia and excess urine protein is observed. IGS is a manageable condition with regular B12 or cobalamin supplementation.  However, without treatment permanent brain and nervous system damage can occur.

IGS in Beagles and Border Collies are caused by independent mutations in the cubulin (CUBN) gene. IGS is inherited in an autosomal recessive trait with both sexes being equally affected.  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.

Testing for inherited IGS in Beagles and Border Collies is important in assisting clinicians, owners, and breeders in identifying affected and carrier dogs. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing affected dogs.

Turnaround Time
3-6 business days

Species

Dog

Type of Test

Results Reported As
Test Result Imerslund-Gräsbeck Syndrome
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.
References

Owczarek-Lipska, M., Jagannathan, V., Drögemüller, C., Lutz, S., Glanemann, B., Leeb, T., & Kook, P.H. (2013). A frameshift mutation in the cubilin gene (CUBN) in Border Collies with Imerslund-Gräsbeck syndrome (selective cobalamin malabsorption). PLOS ONE 8(4): e61144. doi: 10.1371/journal.pone.0061144

Fyfe, J.C., Hemker, S.L., Venta, P.J., Fitzgerald, C.A., Outerbridge, C.A., Myers, S.L., & Giger, U. (2013). An exon 53 frameshift mutation in CUBN abrogates cubam function and causes Imerslund-Gräsbeck syndrome in dogs. Molecular Genetics and Metabolism, 109(4), 390-396. doi: 10.1016/j.ymgme.2013.05.006

Drögemüller, M., Jagannathan, V., Howard, J., Bruggmann, R., Drögemüller, C., Ruetten, M., Leeb, T., & Kook, P.H. (2014). A frameshift mutation in the cubilin gene (CUBN) in Beagles with Imerslund-Gräsbeck syndrome (selective cobalamin malabsorption). Animal Genetics, 45(1), 148-150. doi: 10.1111/age.12094