Prevalence of hyposegmentation/Pelger-Huët anomaly in different canine breeds: a Bayesian approach

Erika Carli^1*Ester Salsecci¹Roberta Calleo¹Ileana Baldi²

• ¹San Marco Clinic and Laboratory, Padua, Italy
• ²Unit of Biostatistics, Epidemiology and Public Health, University of Padua, Padua, Veneto, Italy

Pelger-Huët anomaly (PHA) is a benign congenital hematological disorder first described in humans and sporadically reported in dogs. It has been mainly described in Australian Shepherd Dog (ASD) with a prevalence of 9.8%-13%, where, based on a genetic study, it was recently renamed hyposegmentation (HG). Prevalences for other canine breeds were not reported. This study aims to: 1) estimate the prevalence of HG/PHA in various canine breeds, 2) use a Bayesian approach to quantify the uncertainty of the estimated values, and 3) describe affected breeds not previously reported in the literature.A cross-sectional study was conducted by searching the San Marco Veterinary Clinic and Laboratory (Padua, Italy) CBC database between 2001 and 2024. Data were collected from dogs diagnosed with HG/PHA and from breeds previously reported as potentially affected. A Bayesian analysis was performed to estimate the prevalence of the anomaly and its uncertainty by posterior probabilities obtained from an informative prior model. The analysis adhered to the Bayesian Analysis Reporting Guidelines.The dogs (n=5716) included were German Shepherd (GS, 40%), Dachshund (DA, 22.6%), Cocker Spaniel (CS, 17.3%), Border Collie (BC, 9.5%), ASD (5.9%), Samoyed (SA, 2.2%), Boston Terrier (BT, 1.6%), Australian Cattle Dog (ACD, 0.7%) and Basenji (BA, 0.2%). HG/PHA was observed in 0.45% of overall dogs belonging to ASD (7.1%), SA (0.8%), and DA (0.08%) and was absent in the other breeds. The estimated prevalences were 6.47% (95% credible interval [95% CrI]: 4.22%, 9.18%) in ASD, 0.32% (95% CrI: 0.04%, 1.11%) in SA, 0.2% (95% CrI: 0.02%, 0.86%) in BA, 0.18% (95% CrI: 0.02%, 0.77%) in ACD, 0.16% (95% CrI: 0.02%, 0.64%) in BT, 0.11% (95% CrI: 0.02%, 0.30%) in DA, 0.10% (95% CrI: 0.01%, 0.34%) in BC, 0.08% (95% CrI: 0.01%, 0.25%) in CS, 0.05% (95% CrI: 0.01%, 0.15%) in GS. HG/PHA was described for the first time in DA.This study, based on laboratory database collected over a 20-year period, could be considered representative of the prevalence of HG/PHA in different canine breeds in a real-world setting.