Selective IgA Deficiency

Selective IgA deficiency is an immune system disorder that occurs due to a lack of IgA (immunoglobulin A) immunoproteins. It is the most common primary immune deficiency disorder in both humans and dogs. The immune system produces these proteins in response to the presence of antigens such as bacteria, viruses, and toxins. Antibodies recognize and attack antigens by binding to them and remove them from the body. Immunoglobulin A (IgA) is the second most abundant antibody in human blood and is found on the skin, in the respiratory, digestive and reproductive tracts, and in tears. When the immune system fails to produce sufficient amount of IgA, or does not produce it at all, animals have chronic, recurrent respiratory infections, digestive system disorders, dermatitis, and allergies

The IgA deficiency in the German Shepherd Dog has been associated with severe infections, such as aspergillosis (amost 100% mortality rate), otitis externa, atopic dermatitis, and folliculitis. These infections are generally unresponsive to antibiotic therapy. Affected dogs are usually smaller than their littermates. In puppies, the disease manifests as scratching, sneezing, nasal discharge, chronic diarrhea, and frequent urination. The IgA deficiency is usually diagnosed through blood test which may show reduced or absent IgA. Besides the German Shepherd Dog, the disorder is most commonly diagnosed in the Beagle, Shar-Pei, and Irish Setter.


  1. Genome-Wide Analyses Suggest Mechanisms Involving Early B-Cell Development in Canine IgA Deficiency
  2. Genome-Wide Analysis in German Shepherd Dogs Reveals Association of a Locus on CFA 27 with Atopic Dermatitis

Home Contact RSS