Pelger-Huët anomaly presents an inherited condition marked by the undersegmentation of neutrophils, a type of white blood cell. This disorder manifests with nuclei containing either two lobes or none at all. Primarily benign, it affects various dog breeds such as the American foxhound, Australian shepherd, and basenji.
Symptoms and Types
Pelger-Huët anomaly presents in two forms: heterozygous and homozygous. The heterozygous variation is more prevalent and identifiable by the resemblance of mature neutrophils in dogs to bands (slightly immature neutrophils) and metamyelocytes (precursors of granular leukocytes). This heterozygous anomaly isn’t associated with immunodeficiency, increased susceptibility to infections, or abnormalities in leukocyte function. On the other hand, the homozygous anomaly is typically fatal in utero. In surviving dogs, leukocytes may exhibit round to oval nuclei on a stained blood smear.
Samoyeds have been reported to exhibit both heterozygous anomaly and skeletal anomalies like abnormal cartilage development and shortened jaws. However, a definitive link between Pelger-Huët anomaly and skeletal anomalies in Samoyeds has not been conclusively established.
Causes
Breeding studies with limitations may indicate autosomal (non-sex linked) dominant transmission of the anomaly in dogs. However, in Australian shepherd dogs, autosomal dominant transmission with incomplete penetrance (lacking full genetic expression of the autosomal dominance) has been observed.
Diagnosis
In the majority of cases, veterinarians stumble upon the anomaly in dogs incidentally during routine blood tests. Upon examination of a stained blood smear, nuclear hyposegmentation of neutrophils, eosinophils, basophils, and monocytes becomes evident, wherein the cells’ nucleus displays either two lobes or no lobes at all. The hereditary aspect of the disease is uncovered through the examination of blood smears from both parents and siblings.
Treatment
No treatment is necessary, as Pelger-Huët anomaly is not associated with clinical disease.
Recovery and Management
For those concerned about breeding, seeking genetic counseling can assist in eliminating the trait from future generations.
