Importance of testing horses for genetic disorders highlighted in study

The importance of testing Arabian and Arabian-cross horses in the Middle East and North Africa for key genetic disorders has been highlighted in a just-published study.
Genetic disorders in horses are mostly fatal or cause significant economic losses for breeders and owners.
Abdelhanine Ayad, Saria Almarzook and their fellow researchers noted that Arabian, Barb and Arab-Barb horses are the original breeds in the Middle East and North Africa.
They have been bred close together, geographically, for hundreds of years. The breeds hold a prominent place in the region. They are recognised as influential because of their contribution to many other horse breeds worldwide.
The study team set out to screen Arabian, Barb, and Arab-Barb horses in the region for three genetic disorders — Cerebellar Abiotrophy (CA), which is a progressive neurological disease; Lavender Foal Syndrome (LFS), a lethal genetic coat colour-associated disorder; and Severe Combined Immunodeficiency (SCID), which causes foals to be born with severely weakened immune systems.
In all, follicle hair samples were taken from 177 randomly selected horses, comprising 80 Arabian, 41 Barb, and 56 Arab-Barb horses.
Molecular-based testing showed that all the tested horses were free of the mutated gene responsible for Lavender Foal Syndrome.

However, five of the horses, all of them Arabian, were shown to be carriers of Cerebellar Abiotrophy; and 10 horses were carriers of SCID. The SCID carriers comprised nine Arabian horses and one Arab-Barb horse.
The carriers of these recessive genetic disorders show no clinical signs.
“This investigation shows the importance of testing these breeds for genetic disorders to avoid further spread of deleterious variants,” the researchers wrote in the journal Genes.
Breeders, they said, are becoming more aware of the best procedures to enhance their production and minimise the risks of genetic disorders that might negatively affect their profits. “Therefore, our study strongly supports the need for genetic testing in Arabian and Arabian-crossed horses in the Middle East and North Africa region.”
The study team comprised Ayad and Sofiane Aissanou, with the University of Bejaia in Algeria; Almarzook, with the University of Applied Sciences Europe in Berlin; Omar Besseboua, with the University H. Benbouali in Algeria; and Katarzyna Piórkowska, Adrianna Musiał, Monika Stefaniuk-Szmukier and Katarzyna Ropka-Molik, all with the National Research Institute of Animal Production in Poland.

Ayad, A.; Almarzook, S.; Besseboua, O.; Aissanou, S.; Piórkowska, K.; Musiał, A.D.; Stefaniuk-Szmukier, M.; Ropka-Molik, K. Investigation of Cerebellar Abiotrophy (CA), Lavender Foal Syndrome (LFS), and Severe Combined Immunodeficiency (SCID) Variants in a Cohort of Three MENA Region Horse Breeds. Genes 2021, 12, 1893. https://doi.org/10.3390/genes12121893
The study, published under a Creative Commons License, can be read here.