Severe Combined Immunodeficiency (non-human) - Dogs

Dogs

There are two known types of SCID in dogs, an X chromosome-linked form that is very similar to X-SCID in humans, and an autosomal recessive form that is similar to the disease in Arabian horses and SCID mice.

X-SCID in dogs is seen in Basset Hounds and Cardigan Welsh Corgis. Because it is an X-linked disease, females are carriers only and disease is seen in males exclusively. It is caused by a mutation in the gene for the cytokine receptor common gamma chain. Recurring infections are seen and affected animals usually do not live beyond three to four months. Characteristics include a poorly developed thymus gland, decreased T-lymphocytes and IgG, absent IgA, and normal quantities of IgM. A common cause of death is canine distemper, which develops following vaccination with a modified live distemper virus vaccine. Due to its similarity to X-SCID in humans, breeding colonies of affected dogs have been created in order to study the disease and test treatments, particularly bone marrow transplantation and gene therapy.

The autosomal recessive form of SCID has been identified in one line of Jack Russell Terriers. It is caused by a loss of DNA protein kinase, which leads to faulty V(D)J recombination. V(D)J recombination is necessary for recognition of a diverse range of antigens from bacteria, viruses, and parasites. It is characterized by nonfunctional T and B-lymphocytes and a complete lack of gammaglobulins. Death is secondary to infection. Differences between this disease and the form found in Bassets and Corgis include a complete lack of IgM and the presence of the disease in females.