Page 146 - Aussie Magazine no1, 2023

Inf
Informativeormative

Pelger-Huet

Anomaly

Many of you have seen that in the USA the Pelger–Huet Anomaly
(PHA) test is very popular (in Europe rare). In this article, we will

explore what it means and what we need it for.

Pelger–Huet Anomaly (PHA) is a rare genetically- cells from maturing naturally, leading to possible
inherited condition characterised by abnormal complications. Pelger-Huet anomaly (PHA) is an
white blood cells. Specific dog breeds are known inherited blood condition in which the nuclei of
to be affected by the condition, which include several types of white blood cells (neutrophils and
Cocker Spaniels, Australian Shepherds, Samoyeds, eosinophils) have unusual shape (bilobed, peanut
Foxhounds, Coonhounds, and Basenjis. or dumbbell-shaped instead of the normal trilobed
shape) and unusual structure (coarse and lumpy).
The condition has two phenotypes: heterozygous PHA is considered to be a benign disorder in most
and homozygous variations. Heterozygous instances, as individuals with PHA are typically
conditions are more common and benign. healthy.
Homozygous cases are lethal for affected dogs
in utero or stillborn with physical defects such as Pelger-Huet anomaly is caused by mutations in the
shortened paws and poorly developed cartilage. Lamin B receptor (LBR) gene. It is suspected that
Heterozygous anomaly and skeletal anomalies, mutations within the LBR gene are responsible for a
such as abnormal development of cartilage spectrum of disorders including isolated PHA; PHA
and shortened jaws, are reported in Samoyeds; with mild skeletal symptoms; and hydrops-ectopic
however, a direct link with PHA has not been calcification-moth-eaten skeletal dysplasia (HEM
conclusively confirmed. dysplasia or Greenberg skeletal dysplasia). PHA was
previously thought to be inherited in an autosomal
PHA is a result of genetic abnormalities within dominant manner; however, co-dominant inheritance
various white blood cells (i.e. neutrophils, has been suggested as well. It is important to
basophils, and eosinophils). Mutations such as distinguish Pelger-Huet anomaly from acquired or
hypo segmentation (the low number of lobes pseudo-Pelger-Huet anomaly, which may be found
Text written by: Martina Svecova, Fallcat
in individuals with certain types of leukaemia or
in the nuclei of blood cells) prevent white blood

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