Genetic Disorders
Yorkshire Terriers

Introduction
► When choosing any breed of dog you must be aware of
potential health concerns
► All dogs mixes and pure bred can have health concerns
► The more popular breeds and their mixes will have more
genetic problems listed and more likely to have puppies
with problems .
► Although more serious in dogs under 6 lbs all sizes of
Yorkshires can have any of these health concerns.
► Make sure your breeder offers a written health guarantee
good for one year.
► Have the puppy heath checked at your Veterinarian.

Musculoskeletal Disorders
► Patellar luxation : Slipping kneecap. Should be
noticeable puppy vet check prior to sale
► Legg-Calvé-Perthes disease : This is a
disease of the hip joint in young (4 to 12 months),
small-breed dogs.

Heart Disorders
► Patent ductus arteriosus Where the ductus arteriosus
does not close within 24-48 hours after birth, the dog is left
with a patent ductus arteriosus (PDA). PDA causes
unnecessary recirculation of blood through the heart,
greatly increasing the workload of the heart and potentially
causing terminal heart failure in time if the PDA is not
closed via surgery

Eye Disorders
► Retinal dysplasia : The condition is present from birth. At 3 to 4
weeks of age, the breeder may notice that severely affected pups are
less active and frequently bump into objects. A veterinarian will be best
able to examine the pup's eyes for this condition with an
ophthalmoscope at 12 to 16 weeks of age, when the retina is mature.
► Cataracts : Can be congenital, juvenile or as a result of old age
► Corneal dystrophy : an inherited abnormality that affects one or
more layers of the cornea. Both eyes are usually affected, although not
necessarily symmetrically. Chronic or recurring shallow ulcers may
result, depending on the corneal layers affected
► Keratoconjunctivitis sicca KCS or "dry eye" is an eye disease
caused by abnormal bulk of the tears.

Eye Disorders
► Progressive retinal atrophy : deterioration of the retinal cells causes
blindness.
► Generalized PRA - early onset: The first sign is generally failing night
vision, as early as 6 weeks of age, and this progresses to complete loss of
vision by about 1 - 2 years of age. Collies may retain some vision until the age
of 2 - 3 years. In miniature schnauzers, poor night vision usually develops later
(6 months to a year) and there is advanced loss of vision by 3 to 4 years.
Affected Alaskan malamutes are day-blind (hemeralopia) at 8 to 10 weeks of
age; night vision is never affected.
► Generalized PRA (progressive rod-cone degeneration) - late
onset: Generally night blindness is noticed between 2 and 5 years of age
(depending on the breed) progressing to total blindness within a year or so.
Peripheral vision is lost first.
► Central PRA (CPRA) - retinal pigment epithelial dystrophy
(RPED): Loss of vision occurs much more slowly than in generalized PRA,
without initial night blindness. Affected dogs may not lose vision completely.
Because the changes are in the centre of the retina, affected dogs initially have
trouble locating still objects in bright light.

Eye Disorders
► Entropion : Entropion is the inward rolling of the eyelid,
most commonly the lower lid. This irritates the surface of
the eye (the cornea) and may ultimately cause visual
impairment.

Nervous System Disorders
► Hydrocephalus : an abnormal build-up of cerebrospinal fluid (CSF)
in cavities in the brain (the ventricles). This results in increased
pressure on the brain. Puppies with severe hydrocephalus often die
at a very early age due to pressure from the increased fluid in the
brain. In other less severely affected pups, the signs gradually become
apparent over the first few months of life, and in some mild cases the
condition is only diagnosed later in life.
The types of signs seen with this condition include lack of thriftiness
(smaller than littermates, slow to grow), a domed skull (which gradually
becomes more pronounced), abnormal movement behaviour (e.g.,
restlessness, aimless walking), problems with vision, and seizures.
These pups are very slow to learn - it may be extremely difficult to
housetrain them for example, or they may lose their housetraining.
Generally the signs gradually worsen, although by 2 years of age they
may stabilize. To minimize brain damage, the condition must be
recognized and appropriate treatment begun early. However, affected
animals will likely always be slow and have a limited ability to learn.

Nervous System Disorders
► Shaker dog disease : This disorder usually develops suddenly in
young adult dogs (6 months to 3 years of age). The signs become
progressively worse over 1 to 3 days and then remain the same until
treatment is begun. There is an all-over tremor that can range from
mild to so severe that the dog may have difficulty walking. This is
called an intention tremor, meaning that it is worse when the animal is
excited or tries to perform a specific action (such as eat, walk towards
an object, etc). The tremor decreases or disappears when the dog is
relaxed or at rest. Commonly there are rapid, random eye movements
as well. The condition is not painful and your dog's personality is
unaffected. Treatment is generally effective; some dogs require
medication for life to control the tremors

Skin Disorders
► Dermoid sinus Dermoid sinus is present from birth, although the
condition is usually not noticed until later. The tracts contain debris
from the skin - sebum (waxy lubricating substance), dead skin cells,
and hair - and commonly become infected and painful. If the tract
extends to the spinal canal, infection may cause meningitis or myelitis,
resulting in various neurologic signs such as local or general spinal
pain, stiffness, or weakness (depending on the location of the sinus).
► Hypotrichosis : Dogs with this condition have hair loss at birth or by
a few months of age, due to faulty development or a complete absence
of some or all of the hair follicles from which the hairs normally grow. In
some dogs other structures such as the sweat glands or the teeth are
affected as well. The hair loss is not linked to coat color as with
color dilution alopecia
► Color dilution alopecia : Affected dogs have a poor, patchy hair
coat progressing to widespread permanent hair loss

Blood Disorders
► von Willebrand's disease a common, usually mild, inherited bleeding
disorder in people and in dogs. It is caused by a lack of von Willebrand factor
(vWF), which plays an essential role in the blood clotting process.
Normally the body responds to an injury causing bleeding through a complex
defense system. This consists of local changes in the damaged blood vessels,
activation of blood cells called platelets, and the coagulation process. A
reduction in von Willebrand factor leads to abnormal platelet function and
prolonged bleeding times. Affected dogs are prone to bleeding episodes, such
as nose bleeds, and generally experience increased bleeding with trauma or a
surgical procedure.
Three forms of the disease are distinguished based on vWF concentration and
function. Dogs with Type I vWD (by far the most common) have mild to
moderate bleeding abnormalities, depending on the level of vWF. The much
rarer types II and III vWD cause severe bleeding disorders.
Breeders of quality bred dogs do not have a problem as they now have a blood
test. However poorly bred dogs may still have this problem

Respiratory Disorders
► Tracheal collapse : Tracheal collapse is a narrowing of the inner
diameter of the trachea, that fluctuates with the stage of the respiratory
cycle. The rings of the trachea (made of cartilage) lose their ability to
maintain their shape, and collapse when the dog breathes, causing a
harsh cough. Most often this disorder is seen in middle-aged toy and
miniature breeds. Chronic respiratory infection, obesity, and heart
disease can all contribute to the development of the condition, but it
appears that there is also a congenital deficiency (ie. a dog is born with
it) in the make-up of the trachea itself.

Liver Disorders
► Portosystemic shunt : Portosystemic shunt (PSS) is a
birth defect of the circulation in the liver. Most animals with
congenital portosystemic shunts show symptoms before 6
months of age. When symptoms are subtle, however, the
condition may not be diagnosed until much later. The most
definitive way to deal with PSS is surgery
► Cornel University is doing a study on this defect. Their
findings show an average of 60% are carriers of liver
shunts

Reproductive / Urinary Disorders
Cryptorchidism : Cryptorchidism means that one or
both of a dog's testicles have not descended into the
scrotum
Urolithiasis : a condition in which crystals in the urine
combine to form stones, also called calculi or uroliths.
These can be found anywhere in the urinary tract,
where they cause irritation and secondary infection.
Most end up in the bladder or in the urethra, where they
may cause obstruction, which is a medical emergency.
Several different types of uroliths have been identified,
with struvite stones (magnesium ammonium phosphate)
the most common.

Cushing’s Syndrome
► Hyperadrenocorticism . Hyperadrenocorticism, also
known as Cushing's syndrome, is a common endocrine
disorder in dogs. The clinical signs are caused by an
excess of cortisol (the body's form of cortisone). This
occurs because of increased secretion of cortisol by the
adrenal glands in response to an abnormality in the
pituitary gland in the brain, or because of a tumor in the
adrenal glands themselves. Cushing's syndrome is more
common in certain breeds, usually in dogs that are 6 years
of age or older.

Hypoglycemia Low Blood Sugar
► Seen in puppies 6 to 9 weeks
► Can be fatal . Often occurs without warning.
► Causes : Stress, missing a meal, chilling, too much play and upset
stomach.
► Typical signs: listlessness depression, staggering gate, muscle
weakness, and tremors especially in the face
► Severe sugar drop seizures develop, or puppy become stuperous and
goes into a coma and without help dies.
► Sometimes a puppy appears fine and goes into a coma
► Prolonged or repeated attacks can cause brain damage
► A Veterinarian can rule out other cause such as liver shunt, infections,
or an enzyme or hormone deficiency
► Although not a genetic problem this is mostly seen in young puppies
but can also continue into adulthood and is life threatening.

In Conclusion
► Yorshire Terriers have 21 health concerns Disorders relatively common in
this breed are : Liver shunts, tracheal collapse, patellar luxation and retinal
dysplasia .
► Note above disorder(s) is very common in this breed. Do not take lightly
the other disorders. Some are very serious .
► Information for this presentation as a public service provided by:
www.delayrekennel.com with information provided by :
► A joint initiative of the Sir James Dunn Animal Welfare Centre at the
Atlantic Veterinary College, University of Prince Edward Island, and the
Canadian Veterinary Medical Association..
Permission is granted to reprint pages from the database, provided that
credit is given as follows: Crook A et al. 2011. Canine Inherited Disorders
Database
Photos Wickipedia Encyclopedia

About the Presenter
► Member of the Canine Ambassador Program with Orange Empire Dog Club.
Educating people in the joy canines bring into our lives through their
relationship, interaction, and unconditional love.
► Pet Professional specializing in the training of puppies in Sun Valley since 1974
. Breeder of Silky Terriers and Wire Fox Terriers
► My boarding, training and breeding kennel was awarded Small Business of the
Year 2000
► Better Business Bureau A+ rating
► I have owned and/or bred 21 Conformation Champions including 6
International Champions
► Member and former Vice President of the City of Angels Silky Terrier Club
► Past President of Sun Valley Chamber of Commerce
► Have also served on the boards of Associated Terrier Breeders, Animal Safe
Haven Foundation, United Chambers of Commerce