Research Update 02945-MOU EY2: Understanding the genetic basis of Addison’s disease in Portuguese Water Dogs

Over the first two years of this study, we have focused primarily on sample collection and running an initial set of genetics experiments. We collected samples mostly through PWD-related channels working directly with our collaborators in the PWDF/PWDCA. We also attended the PWD National Specialty in September 2021 and August 2022 to promote the study and collect samples, and we established a collaboration with Dr. Anita Oberbauer at UC Davis to share samples that she had already collected.

To date, we have in hand 131 samples from affected PWDs and 167 samples from unaffected PWDs. Only a subset of these samples (41 affected, 43 unaffected) will qualify for our initial genotyping efforts based upon relatedness and DNA quality, but we are glad to have made such quick progress with sample collection thus far. We plan to continue our outreach efforts to try to reach our goal of 100 affected and 100 unaffected unrelated samples.

In addition to collecting DNA and cortisol samples from affected/unaffected dogs, we recently received back our first set of sequencing data for an initial genome-wide association study (28 affected PWDs and 35 unaffected PWDs). We did not find any significant hits, but this is expected as our enrollment number for unrelated dogs is still low. We are in the process of actively collecting samples from Europe to gain more dogs and also minimize relatedness to our existing population. We plan to submit another set of dogs for sequencing in the next several months once we have received additional unrelated samples.

We also performed an initial analysis of the variations in a set of genes called the major histocompatibility complex genes. These genes are very important in the immune system. We found one “version” of this gene set that appears to  be associated with Addison’s disease in PWDs. WE will continue to verify this finding as we enroll more dogs in the study.