IGS is an inherited disorder that affects the absorption of vitamin B12. The resulting deficiency impairs blood formation and can lead to anemia as well as neurological deficits. The first symptoms usually appear during puppyhood, between about 6 and 12 weeks of age. Typical symptoms include insufficient weight gain and growth retardation, fatigue, loss of appetite, anemia, and general weakness.

Effective immediately, the IGS genetic test is available for Australian Shepherds and Miniature American Shepherds, in addition to Border Collies, Beagles, and Komondors. For these two breeds, testing is conducted for an autosomal recessive variant in the so-called AMN gene.

Early diagnosis allows affected dogs to maintain a good quality of life through lifelong vitamin B12 supplementation. Genetic testing also helps prevent the birth of affected puppies through targeted breeding planning.