Abstract: Background: Thrombocytopenia is the most common canine hemostatic disorder. Non-clinical congenital macrothrombocytopenia in Cavalier King Charles Spaniels (CKCS) is caused by a mutation in the β1-tubulin gene. The prevalence of this gene mutation in non-CKCS dogs has not been thoroughly investigated.
Hypothesis/Objectives: To determine the prevalence of the currently reported CKCS β1-tubulin mutation associated with macrothrombocytopenia in non-CKCS dogs with macrothrombocytopenia
Animals: Sixty-one client owned dogs with macrothrombocytopenia
Methods: This is a prospective observational descriptive study. Blood samples were banked from patients presenting to the UW Veterinary Care in which a thrombocytopenia was noted. The medical records of these dogs with a noted macrothrombocytopenia (platelet count < 175 *10^3/uL, MPV > reference) between April 2021 to March 2022 were reviewed. Blood samples were submitted for DNA extraction and PCR testing to evaluate for the presence of the known mutations in the TUBB1 gene.
Results: 61 dogs were noted to have a macrothrombocytopenia with no documentation of normal values. There were 32 females (52.5%) and 29 males (47.5%), and the most common included breeds were German Shepherd Dogs (n=5), Golden Retrievers (n=5), and Boxers (n=5). The median platelet count was 110 *10^3/uL (range 9 – 171). The number and proportion of dogs of each breed positive for the β1-tubulin mutation will be reported, and the demographic and clinical histories for positive dogs will be presented.
Conclusions/Clinical importance: The presence of β1-tubulin mutations in non-CKCS dogs would indicate that testing for this mutation should be integrated into a diagnostic evaluation of macrothrombocytopenic dogs.
