Research Update 02945-MOU MY3: Understanding the genetic basis of Addison’s disease in Portuguese Water Dogs

Over the first 2.5 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 134 samples from affected PWDs and 169 samples from unaffected PWDs. Only a subset of these samples (46 affected, 55 unaffected) will qualify for our genotyping efforts based upon relatedness and DNA quality, but we are glad to have made such quick progress with sample collection thus far. While these numbers fall short of our original goal, we plan on evaluating our second batch of association data (see below) before proceeding with further sample collection, as it is possible that our current number of dogs will suffice.

In addition to collecting DNA and cortisol samples from affected/unaffected dogs, we recently received back our second set of sequencing data for an initial genome-wide association study (we now have a total of 46 affected PWDs and 65 unaffected PWDs). We are in the process of analyzing this large dataset, and hope to have some initial analysis of this data completed in the next 1-2 months.

We also performed an updated 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 – which is consistent with what we found in the last progress report. We will continue to verify this finding as we enroll more dogs in the study.