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Pelger-Huët anomaly in an Arabian horse.
Abstract: A 9-year-old Arabian mare was evaluated for a 7-day history of malaise. Results of a CBC included a leukocyte concentration within the reference interval (8.4 x 10(3)/microL, reference interval 6.0-14.0 x 10(3)/microL) with an apparent degenerative left shift (segmented neutrophils 1.2 x 10(3)/microL, reference interval 2.5-7.5 x 10(3)/microL; hyposegmented neutrophils 1.8 x 10(3)/microL, reference interval 0.0-0.2 x 10(3)/microL). Serum clinical chemistry results included increased aspartate transaminase, alkaline phosphatase, and gamma-glutamyltransferase activities. A presumptive diagnosis of hepatitis or cholangiohepatitis was made. The horse was treated with antimicrobials and the malaise quickly resolved. However, in a recheck CBC on day 13, the apparent degenerative left shift remained. Further evaluation of the blood smear revealed many hyposegmented granulocytes with coarse mature chromatin and normal cytoplasmic features. On the basis of the microscopic examination, the horse was diagnosed with Pelger-Huët anomaly. The patient's offspring was subsequently also diagnosed with Pelger-Huët anomaly on the basis of blood film examination. Neutrophil, eosinophil, and basophil mean nuclear scores in both affected horses (mare, range 1.5-2.6; offspring, range 1.6-3.2) were lower than those in 2 unrelated Arabian horses (range, 2.8-5.0) and 5 non-Arabian control horses (range, 2.8-5.0). Results of immunophenotyping and phagocytosis/oxidative burst assays via flow cytometry showed no difference in the expression of myeloid-specific or adhesion molecules or in neutrophil function between affected and control horses. This is the second known report of equine Pelger-Huët anomaly, both of which affected Arabian horses.
Publication Date: 2007-09-07 PubMed ID: 17806084DOI: 10.1111/j.1939-165x.2007.tb00231.xGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
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Summary
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This study investigates the case of a 9-year-old Arabian mare diagnosed with Pelger-Huët anomaly, a condition affecting white blood cells. Anomalies in the horse’s blood and the appearance of similar symptoms in its offspring led to this diagnosis. Despite this condition, the horse’s neutrophil function was found to be normal, marking the second documented case of Pelger-Huët anomaly in equine species.
Symptoms and Diagnosis
- The Arabian mare was assessed due to a 7-day period of malaise. Upon examination, findings from the complete blood count (CBC) showed a leukocyte concentration that was within the normal range.
- However, there was an apparent degenerative left shift, with a lower number of segmented neutrophils and a higher number of hyposegmented neutrophils than the average.
- The clinical chemistry results also recorded increased aspartate transaminase, alkaline phosphatase, and gamma-glutamyltransferase activities. These observations suggested a possible diagnosis of hepatitis or cholangiohepatitis.
- Although treated with antimicrobials and the horse’s condition improved, the degenerative left shift was still observed in another CBC conducted on day 13. A thorough examination of the blood smear revealed numerous hyposegmented granulocytes, which resulted in diagnosing the horse with Pelger-Huët anomaly.
Offspring and Control Group Comparisons
- Interestingly, the offspring of the mare was also diagnosed with Pelger-Huët anomaly, highlighting the hereditary nature of the condition.
- The study compared neutrophil, eosinophil, and basophil mean nuclear scores between the affected horses and control horses (two unrelated Arabian horses and five non-Arabian horses).
- The scores for both the mare and her offspring were lower than those of the control horse groups.
Comparison of Neutrophil Function
- Despite the anomaly, tests conducted showed no difference in neutrophil function or expression of myeloid-specific or adhesion molecules between the affected and the control horses.
- This implies that the Pelger-Huët anomaly did not affect the normal functioning of the white blood cells in the affected horses.
- This is the second documented case of an equine Pelger-Huët anomaly, with Arabian horses being the affected breed in both instances.
Cite This Article
APA
Grondin TM, DeWitt SF, Keeton KS.
(2007).
Pelger-Huët anomaly in an Arabian horse.
Vet Clin Pathol, 36(3), 306-310.
https://doi.org/10.1111/j.1939-165x.2007.tb00231.x Publication
Researcher Affiliations
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA. tgrondin@vet.k-state.edu
MeSH Terms
- Animals
- Female
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horses
- Lymphocytes / pathology
- Pelger-Huet Anomaly / diagnosis
- Pelger-Huet Anomaly / pathology
- Pelger-Huet Anomaly / veterinary
Citations
This article has been cited 2 times.- Lourdes Frehner B, Christen M, Reichler IM, Jagannathan V, Novacco M, Riond B, Peters LM, Suárez Sánchez-Andrade J, Pieńkowska-Schelling A, Schelling C, Kipar A, Leeb T, Balogh O. Autosomal recessive hyposegmentation of granulocytes in Australian Shepherd Dogs indicates a role for LMBR1L in myeloid leukocytes. PLoS Genet 2023 Jun;19(6):e1010805.
- Carli E, Salsecci E, Calleo R, Baldi I. Prevalence of hyposegmentation of granulocytes/Pelger-Huët anomaly in different canine breeds: a Bayesian approach. Front Vet Sci 2025;12:1602474.
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