Page 147 - Aussie Magazine no1, 2023

A B C

myelodysplastic syndromes. Diagnosis is made based
on characteristic appearance of white blood cell
nuclei identified by a blood smear. Most individuals
with PHA do not require treatment as they do not D E F
have symptoms.

The diagnosis of PHA is based on the morphologic
characteristics of the neutrophils observed on
peripheral blood film examination. When a complete
blood count (CBC) is requested, digital analysers
will report a shift to the left without identifying the GRADING PODLE BOWLESE
specific anomaly of the neutrophils.
A – neutrofil, grade 1 D – neutrofil, grade 4
The heterozygous version is more common and is B – neutrofil, grade 2 D – neutrofil, grade 4
recognised because the dog's mature neutrophils C – neutrofil, grade 3 F – monocyt, hypolobulace
resemble bands (slightly immature neutrophils)
and metamyelocytes (a predecessor of granular
leukocytes). Heterozygous anomaly is not associated PHA status of breeding dogs can be determined
with immunodeficiency, with predisposition to by examination of a blood smear by a veterinary
infection, or with abnormalities of leukocyte (white pathologist. Most PHA carriers have minor
blood cell) function. Conversely, the homozygous anomalies in some of their blood cells. However,
anomaly is usually lethal in utero. Dogs that survive not every PHA carrier will exhibit these anomalies
may have leukocytes with round to oval nuclei on a so it is possible to receive false negative results
stained blood smear. from this test. Therefore, any breeding dog with
near relatives known to be PHA carriers should
The condition is inherited as an incomplete dominant. be tested. PHA carrier dogs should not be bred to
Dogs with only one gene are almost always healthy, each other. If a breeding dog has extremely variable
but if bred to another carrying the mutation the litter sizes it may be a PHA carrier and should be
pups that receive two copies of the PHA gene will screened.
be reabsorbed, stillborn or die shortly after birth.
Occasionally a puppy will survive but have severe In most cases, veterinarians discover the anomaly
skeletal deformities and be susceptible to infection. in your dog by accident while conducting routine
blood tests. On a stained blood smear, nuclear hypo
PHA is more of breeder’s problem than an owner's segmentation of neutrophils, eosinophils, basophils,
problem, as puppies with two copies of the PHA and monocytes will be visible, whereby the nucleus
gene almost never survive, and if they do, they will of the cells has only two lobes or no lobes at all.
have severe health issues. PHA causes small litters The hereditary nature of disease is revealed by
or loss of new-borns. examination of blood smears from parents and
siblings. But of course, you can ask your vet to check
The PHA gene has not yet been found; but the your Aussie for PHA.

A Worldwide Magazine for the Aussie • Issue 1/2023 | 147