UC Davis links RESF1 variant to juvenile Addison’s in Tollers

UC Davis researchers have identified a missense variant in RESF1 that is strongly associated with juvenile-onset Addison’s disease in Nova Scotia Duck Tolling Retrievers, and the finding is now paired with a commercially available genetic test through the university’s Veterinary Genetics Laboratory. In the newly published Scientific Reports paper, the team described 24 juvenile-onset cases and found that at least 10 dogs also had concurrent autoimmune conditions, supporting the idea that this form of Addison’s in Tollers may be part of a broader multiple autoimmune syndrome rather than an isolated endocrinopathy. The paper was published March 12, 2026, with the version of record posted April 23, 2026. (nature.com)

Why it matters: For veterinarians, the discovery adds genetic context to a breed already known to be overrepresented for hypoadrenocorticism and may help explain why some young Tollers present with endocrine disease alongside ocular or other immune-mediated findings. UC Davis says the juvenile form averages about 5 months of age at presentation, is inherited as an autosomal recessive trait with incomplete penetrance, and carries roughly a 75% risk of disease by 1 year in dogs testing positive for two copies of the variant. That creates a practical opening for earlier breeder counseling, more informed diagnostic suspicion in sick puppies, and clearer conversations with pet parents about risk in related dogs. (vgl.ucdavis.edu)

What to watch: Expect follow-up work on how broadly this test is adopted in Toller breeding programs, and whether RESF1 becomes a candidate gene in human Addison’s disease research. (ucdavis.edu)