Horse

Occipitoatlantoaxial malformation (OAAM) is a deformity of the first two vertebrae causing bone marrow compression and neurological damage. The mutation tested is associated with one of the forms of OAAM.

Junctional epidermolysis bullosa (JEB), also known as red foot disease, causes blistering of the skin epithelium and absence of skin on the lower limbs at birth. Affected foals are usually euthanised.

Malignant hyperthermia (MH) is characterised by muscle twitching, high temperature and irregular heartbeat. These symptoms can be triggered by halogenated anaesthetics, succinylcholine, stress or excitement.

MYHM is a muscle disease in horses, presenting as immune-mediated myositis or non-exertional rhabdomyolysis. Detected through the MYH1 gene, it causes stiffness, muscle weakness, and rapid loss of muscle mass. Environmental triggers like infection or vaccination can activate the disease, especially in younger or older horses. Testing helps breeders avoid producing affected horses and guides vaccination decisions, contributing to better management strategies.

A horse’s height depends on genetic and environmental factors. A genetic variation in the regulatory region of the LCORL gene strongly influences the height of warmblood horses (+/- 5 cm). The effect of this variation is less predictable in non-warmblood breeds.

This panel includes specific analyses related to agouti (HORSE-AG) and extension (HORSE-EXT) coat colour

The Agouti gene controls the distribution of black pigment and determines whether a horse will have a bay or black coat. The effect of the agouti gene is to be combined with the extension gene to obtain the three basic coat colours. Horses carrying the E allele of the extension gene are black if they have two copies of the a allele of the agouti gene and bay if they have at least one copy of the A allele of the agouti gene.

The Extension (red factor) gene codes for the MC1R protein which produces the black pigment (eumelanin). The dominant allele E produces a black pigment in the coat and the recessive allele e produces a red pigment. A horse with two copies of the e allele will have a chestnut coat. A horse with one or two copies of the E allele will have a bay or black coat. The effect of the extension gene is to be combined with the agouti gene (HORSE-AG) to obtain the three basic coat colours.

Lavender Foal Syndrome (LFS) is a genetic disease that causes severe neurological symptoms. Affected foals are unable to stand, have seizures, show hyperextension of the limbs, have involuntary eye movements and have a pink (lavender) coat. Affected foals die soon after birth and are usually euthanised.

The Overo horse has a specific white spotted pattern. These horses are heterozygous for a mutation (one copy of the allele) which is lethal in the homozygous state (two copies of the mutated allele) as white foals die from complications due to abnormalities of the intestinal tract.