Hyposegmentation of Granulocytes (HG) – Australian Shepherd

Hyposegmentation of Granulocytes (HG) in Australian Shepherds is caused by an autosomal recessive mutation in the LMBR1L gene. This mutation alters the morphology of the nucleus in granulocytes, a type of leukocyte (white blood cell). Normally, the nucleus of granulocytes has two to four segments, but with hyposegmentation, fewer segments are present.
HG can occur either primarily due to the mutation in the LMBR1L gene or secondarily as a result of other conditions, such as leukemia or radiation exposure.
Interestingly, HG in dogs presents a phenotype similar to Pelger-Huët anomaly (PH) in humans. However, dogs with primary HG do not appear to have an increased predisposition to infection or immunodeficiency. This means that primary HG itself does not require treatment.

Although primary HG is not harmful or disease-causing on its own, it is helpful for owners and veterinarians to know if an Australian Shepherd carries the mutation. Affected dogs exhibit hyposegmented granulocytes on a blood smear. Recognizing this as a benign, coincidental finding - rather than a symptom of a disorder - can prevent unnecessary concern. Furthermore, the DNA test for HG serves as a useful diagnostic tool. If an Australian Shepherd shows hyposegmentation of granulocytes but does not carry the LMBR1L mutation (i.e., is free of or a carrier of the mutation), other potential causes of hyposegmentation should be investigated and treated accordingly.

Pubmed ID: 37347778

Year published: 2023

Omia ID: 2700

Omia variant ID: