Macrothrombocytopenia in a group of related Norfolk terriers

Validation of Advia plateletcrit for assessing platelet mass in dogs, including Cavalier King Charles Spaniels

“…The PCT and MPV as measured by the Advia 2120 were able to identify changes in platelet mass and size, respectively, in CKCS dogs, but PCT values were lower than those obtained by QBC analysis, especially in CKCS dogs with the lowest PCT. The basic assumption underlying this study was that the QBC platelet count, calculated from the PCT, is the gold standard for comparison, as the QBC calculated platelet count accurately reflects the normal PCT found in CKCS and Norfolk terrier dogs with large but reduced numbers of platelets . The QBC platelet count in dogs, including dogs with normal‐sized platelets, was validated previously and found to be accurate and reliable .…”

“…Passing‐Bablok scatterplots were configured in 2 ways: first comparing Advia PCT (%) and QBC calculated platelet counts (platelets/L) and next comparing Advia PCT × the conversion factor (×1000) and QBC calculated platelet counts (platelets/L). Reference values (95%) for Advia platelet count, MPV, and PCT used for comparison and established for the non‐CKCS dogs in group 2 were calculated using the nonparametric reference value method of Analyze‐it and the nonparametric and robust method with Box‐Cox transformation using Reference Value Advisor, including assessment of normality using the Anderson‐Darling A method with statistical significance set at P < .05. Comparison and difference plots of paired results were analyzed visually.…”

“…Thus, Sysmex does not release MPV or PCT values for most cats or dogs with severe thrombocytopenia or for breeds of dog with macrothrombocytopenia. In addition, the impedance method of quantifying platelets fails to detect larger platelets, and platelet counts in CKCS dogs and Norfolk terriers with macrothrombocytopenia and cats with large platelets are more accurate using the optical method …”

A novel point mutation in the β1‐tubulin gene in asymptomatic macrothrombocytopenic Norfolk and Cairn Terriers

“…Recently, a phenotypically similar macrothrombocytopenia was described in a group of related Norfolk Terriers (NT) from Northern Italy, and isolated cases of asymptomatic macrothrombocytopenia were also reported in Cairn Terriers (CT) . The purpose of this work was to evaluate for the presence of a genetic defect in the β1‐tubulin gene in macrothrombocytopenic NT and CT in different countries.…”

Platelet Disorders

“…25 A mutation in β1-tubulin likely leads to altered proplatelet formation in megakaryocytes. 27 CKCS have not been found to have any clinical bleeding 28,29 or any abnormalities on platelet aggregation testing. 27 CKCS have not been found to have any clinical bleeding 28,29 or any abnormalities on platelet aggregation testing.…”