IGS - Cobalamin Malabsorption (Imerslund-Gräsbeck Syndrome)

The Disease

Cobalamin malabsorption (merslunf-Gräsbeck Syndrome (IGS) refers to a genetic disorder by which the vitamin B12, also known as cobalamin, fails to be absorbed from the intestine. Lack of cobalamin leads to changes in the hematopoietic system and to neurological symptoms due to irreversible damage of the brain and nervous system. Symptoms include anorexia, lethargy and failure to gain weight. Cobalamin malabsorption can be managed by supplementation with regular doses of cobalamin.

Trait of Inheritance

IGS follows an autosomal recessive mode of inheritance.

Clear                     

Genotype: N / N [ Homozygous normal ]

The dog is noncarrier of the mutant gene.

It is very unlikely that the dog will develop Cobalamin Malabsorption (Imerslund-Gräsbeck syndrome (IGS)). The dog will never pass the mutation to its offspring, and therefore it can be bred to any other dog.

Carrier

Genotype: N / IGS [ Heterozygous ]

The dog carries one copy of the mutant gene and one copy of the normal gene.

It is very unlikely that the dog will develop Cobalamin Malabsorption (Imerslund-Gräsbeck syndrome (IGS)) but since it carries the mutant gene, it can pass it on to its offspring with the probability of 50%.

Carriers should only be bred to clear dogs.

Avoid breeding carrier to carrier because 25% of their offspring is expected to be affected (see table above)

Affected

Genotype: IGS / IGS [ Homozygous mutant ]

 The dog carries two copies of the mutant gene and therefore it will pass the mutant gene to its entire offspring.

The dog is likely to develop Cobalamin Malabsorption (Imerslund-Gräsbeck syndrome (IGS)) and will pass the mutant gene to its entire offspring