Horse Science ANSI 4423
Homework Assignment 1
Equine Genetic Diseases
Due- Tuesday, January 30 at midnight
Submit on Dropbox A.
For each one of the following diseases listed in the table below, briefly (1-2 sentences)
describe each of
the following:
a.
HYPP
i.
Hyperkalemic Periodic Paralysis is an autosomal dominant trait associated with the Quarter horse Impressive. ii.
HYPP was caused by a missense mutation and failed sodium channels to activate. This causes muscle weakness and depolarization.
iii.
Horses can be either asymptomatic or have daily episodes of muscle weakness. A severe symptom is the constriction of the upper respiratory airway.
iv.
Light exercise can help treat the disease. Decreasing potassium and increasing renal losses of potassium can prevent episodes.
b.
PSSM
i.
Polysaccharide Storage Myopathy is an autosomal dominant disease affecting glycogen storage in many registered horse breeds.
ii.
The mutation is a 10-single base-pair substitution in the glycogen synthase one gene located on chromosome 10.
iii.
Signs occur around 5 years old and are shown by muscle pain, stiffness, sweating, etc.
iv.
Stall confinement and hydration help treat the disease, and sticking to a strict exercise and diet plan helps with control.
c.
GBED
i.
Glycogen Branching Enzyme Deficiency is an autosomal recessive disease affecting Quarter and Paint horses and causes foals to be aborted or stillborn.
ii.
Glycogen isn’t used throughout the body properly, causing internal organs to shut down.
iii.
Affected foals are mainly stillborn or aborted. If a live foal is born, foals appear hypothermic and weak and eventually die due to heart or respiratory failure.
iv.
There is no treatment for the disease, but testing foals/dams can prevent the disease from passing carrier DNA.
d.
HERDA
i.
Hereditary Equine Regional Dermal Asthenia is an autosomal recessive disease that affects Quarter horses, similar to EDS in humans.
ii.
The exact cause of the genetic mutation is unknown.
iii.
Symptoms of HERDA start around the time of saddle breaking and cause open wounds where the saddle sits.
iv.
There is no treatment for the disease, but lesions occur less in the winter.
e.
OLWS
i.
Overo Lethal White Foal Syndrome is an autosomal recessive trait affecting mainly Paint
and Quarter horses. Foals are born mainly/all white and die due to colic.
ii.
The cause (etiology) of the disease.
iii.
Foals are born all/mainly white and showing signs of intestinal tract abnormalities, causing colic in the first 12 hours of life.
iv.
There’s no treatment or way to control the disease.
(
Refer to Equine Genetic Diseases online under Related Articles
)
