Equine Regional Dermal Asthenia (HERDA) also known as Hyperelastosis
Cutis (HC) is a genetic skin disease predominately found in the
American Quarter Horse. Researchers at Mississippi State University
and Cornell University believe that the origin of this genetic disorder
may be the Poco Bueno's sire line. Symptoms of this disorder is
a lack of adhesion within the layers of skin due to a genetic defect
in the collagen that holds the skin in place. This defect causes
the outer layer of skin to split or separate from the deeper layers
sometimes tearing off completely. Areas under saddle seem to be
most prone to these lesions often leaving permanent scares, preventing
the horse from being ridden. The disorder is recessive, which means
that a horse must be homozygous positive or have two copies of the
defective gene to suffer from the disease. Consequently both the
sire and the dam must possess at least one copy of the mutated gene
in order for the offspring to be afflicted. Offspring born with
one copy of the defective gene and one non-defective copy are considered
a carrier and have a 50% chance of passing the defective gene on.
there is no cure for the disorder, Animal Genetics has developed
a simple DNA test to detect a single nucleotide polymorphism (SNP)
mutation with a high degree of association to this disorder.
Animal Genetics offers
DNA testing and detection of the gene mutation responsible for Hereditary
Equine Regional Dermal
Asthenia (HERDA) also known as hyperelastosis cutis (HC).
US per sample.
Collect sample by pulling (not cutting) 20-30
mane or tail hairs with roots attached. It is important that you
pull the hairs and confirm that the actual root of the hair is being
collected. The root contains the genetic material of your horse
that is needed for DNA testing. Therefore, cut hairs do not provide
an adequate sample of your horse. Place the collected hairs of each
horse in a separate zip-lock bag labeling the bags accordingly with
the horses name or identification number. Download and complete
a submission form for each sample and send along with
payment to Animal Genetics for testing.
Results are given using the following symbolic
horse carries two copies of the HERDA gene and is homozygous
for HERDA. The horse is affected with the HERDA genetic disorder.
the normal and HERDA alleles were detected. Horse tested heterozygous
for HERDA and is a carrier of the HERDA gene.
tested negative for the HERDA gene.