Severe Combined Immunodeficiency (SCID, RAG1-related) – Wetterhoun

Severe Combined Immunodeficiency (SCID) is a group of hereditary disorders characterised by a severely impaired or non‑functional adaptive immune system. Affected animals are unable to produce functional T‑ and B‑lymphocytes, which are essential for fighting infections. As a result, even mild pathogens can cause severe or life‑threatening illness.

This specific variant, identified in the Wetterhoun, is caused by an autosomal recessive mutation in the Recombination Activating Gene 1 (RAG1) gene. RAG1 plays a crucial role in the development and maturation of lymphocytes (a type of white blood cell). When this gene is defective, the immune system cannot form the diverse antigen receptors needed for normal immune responses.

Affected puppies typically begin showing signs early in life, often within the first weeks to months, as their immune system fails to protect them from common environmental pathogens. Clinical features may include chronic or recurrent diarrhea, poor growth, and failure to thrive due to persistent infections.

Neurological signs such as epileptic seizures or vestibular ataxia (loss of balance and coordination) may occur secondarily to severe or recurrent infections, for example due to meningitis, encephalitis, or inner‑ear infections.

Because the immune system is severely compromised, affected dogs are highly susceptible to bacterial, viral, and fungal infections, which may present as respiratory disease, skin infections, or systemic illness. Without a functional adaptive immune response, these infections often progress rapidly and can become fatal.

Overall, SCID is a severe and life‑limiting condition, and affected animals typically have a markedly reduced life expectancy due to their inability to mount an effective immune response.

Pubmed ID: 21293384

Year published: 2011

Omia ID: 1574

Omia variant ID: