Genetic Disorders Genetic Disorders

Shih TzuShih Tzu

IntroductionIntroduction

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

Eye Disorders Eye Disorders

Exposure keratopathy syndrome (exophthalmos, lagophthalmos, and/or maExposure keratopathy syndrome (exophthalmos, lagophthalmos, and/or macroblepharoncroblepharon

)) With this syndrome, there is chronic irritation of the surface of With this syndrome, there is chronic irritation of the surface of the eye (the cornea) because of increased evaporation of tears the eye (the cornea) because of increased evaporation of tears and increased corneal exposure. This is a result of a and increased corneal exposure. This is a result of a combination of anatomic features including exophthalmos combination of anatomic features including exophthalmos (protrusion of the eyeball), lagophthalmos (inability to close the (protrusion of the eyeball), lagophthalmos (inability to close the eyelids completely) andmacroblepharon (an exceptionally large eyelids completely) andmacroblepharon (an exceptionally large eyelid opening, often associated with lower lid eyelid opening, often associated with lower lid entropionentropion). The ). The result is inadequate blinking, and therefore reduced protection for result is inadequate blinking, and therefore reduced protection for the eye. Affected dogs experience chronic discomfort and are prone the eye. Affected dogs experience chronic discomfort and are prone

to ulceration of the corneato ulceration of the cornea..

Eye Disorders Eye Disorders

Retinal dysplasiaRetinal dysplasia: : The condition is present from birth. At 3 to 4 The condition is present from birth. At 3 to 4 weeks of age, the breeder may notice that severely affected pups weeks of age, the breeder may notice that severely affected pups are less active and frequently bump into objects. A veterinarian will 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 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 ophthalmoscope at 12 to 16 weeks of age, when the retina is mature.mature.

CataractsCataracts: : Can be congenital, juvenile or as a result of old age Can be congenital, juvenile or as a result of old age

Keratoconjunctivitis siccaKeratoconjunctivitis sicca KCS or "dry eye" is an eye disease KCS or "dry eye" is an eye disease

caused by abnormal bulk of the tearscaused by abnormal bulk of the tears. . EntropionEntropion : : Entropion is the inward rolling of the eyelid, most Entropion is the inward rolling of the eyelid, most commonly the lower lid. This irritates the surface of the eye (the commonly the lower lid. This irritates the surface of the eye (the cornea) and may ultimately cause visual impairment.cornea) and may ultimately cause visual impairment.

Eye DisordersEye DisordersProgressive retinal atrophyProgressive retinal atrophy: : deterioration of the retinal cells causes blindness. deterioration of the retinal cells causes blindness. Generalized PRA - early onset:Generalized PRA - early onset: The first sign is generally failing night vision, as 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 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 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 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 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.(hemeralopia) at 8 to 10 weeks of age; night vision is never affected.

Generalized PRA (progressive rod-cone degeneration) - late onset:Generalized PRA (progressive rod-cone degeneration) - late onset: Generally Generally night blindness is noticed between 2 and 5 years of age (depending on the breed) 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.progressing to total blindness within a year or so. Peripheral vision is lost first.

Central PRA (CPRA) - retinal pigment epithelial dystrophy (RPED): Central PRA (CPRA) - retinal pigment epithelial dystrophy (RPED): Loss of vision Loss of vision occurs much more slowly than in generalized PRA, without initial night blindness. 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 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. of the retina, affected dogs initially have trouble locating still objects in bright light.

Eye DisordersEye Disorders

EctropionEctropion Ectropion is a defect of conformation in which there is a Ectropion is a defect of conformation in which there is a sagging or rolling-out (eversion) of the eyelids. This results in sagging or rolling-out (eversion) of the eyelids. This results in abnormal exposure of the eye, which often leads to irritation. abnormal exposure of the eye, which often leads to irritation. Eyelash abnormalitiesEyelash abnormalities Normally the eyelashes (or cilia) grow Normally the eyelashes (or cilia) grow from follicles in the eyelid. Abnormalities of the eyelash are a from follicles in the eyelid. Abnormalities of the eyelash are a common hereditary problem in dogs. The three types are:common hereditary problem in dogs. The three types are:distichiasis, in which extra eyelashes grow from abnormal distichiasis, in which extra eyelashes grow from abnormal follicles located on the inside edge of the eyelid. They may be follicles located on the inside edge of the eyelid. They may be singular or multiple. singular or multiple.

ectopic cilia, in which the extra eyelash grows through the ectopic cilia, in which the extra eyelash grows through the eyelid to the inside.One or more ectopic cilia may be present. eyelid to the inside.One or more ectopic cilia may be present.

trichiasis, in which eyelashes growing from normal sites turn trichiasis, in which eyelashes growing from normal sites turn inward. The eyelashes are often abnormally long.inward. The eyelashes are often abnormally long.

Eye Disorders Eye Disorders

Third eyelid (nictitating membrane) abnormalities - "cherry eye"Third eyelid (nictitating membrane) abnormalities - "cherry eye" A A prolapse of the glandprolapse of the gland or "cherry eye" occurs when the base of the or "cherry eye" occurs when the base of the gland (embedded in the cartilage) flips up and is seen above and gland (embedded in the cartilage) flips up and is seen above and behind the border of the third eyelid. The prolapsed gland becomes behind the border of the third eyelid. The prolapsed gland becomes swollen and inflamed. The condition frequently occurs in both eyes swollen and inflamed. The condition frequently occurs in both eyes and is most common in young dogs and is most common in young dogs

Heart DisordersHeart Disorders

Tricuspid valve dysplasiaTricuspid valve dysplasia Dogs with a mildly or even moderately Dogs with a mildly or even moderately malformed tricuspid valve routinely live normal lifespans. However, malformed tricuspid valve routinely live normal lifespans. However, dogs with severe tricuspid valve malformations, even as pups, may dogs with severe tricuspid valve malformations, even as pups, may develop symptoms of congestive heart failure, especially a bloated, develop symptoms of congestive heart failure, especially a bloated, pot-bellied appearance due to fluid pooling in the abdomen pot-bellied appearance due to fluid pooling in the abdomen (ascites), difficulty breathing due to fluid retention in the chest cavity (ascites), difficulty breathing due to fluid retention in the chest cavity (pleural effusion), or both. Such severely affected dogs require (pleural effusion), or both. Such severely affected dogs require medications to reduce the impact of the problem and maintain an medications to reduce the impact of the problem and maintain an acceptable quality of lifeacceptable quality of life

Cleft Lip /palate Cleft Lip /palate

Cleft lip/palateCleft lip/palate This is an opening in the lip or the roof of the This is an opening in the lip or the roof of the mouth that occurs due to failure of normal fusion processes mouth that occurs due to failure of normal fusion processes during embryonic development. Cleft palate and cleft lip may during embryonic development. Cleft palate and cleft lip may result from either hereditary or environmental causes (such as result from either hereditary or environmental causes (such as the use of certain drugs during pregnancy).the use of certain drugs during pregnancy).Affected pups are born with the condition. A minor defect will Affected pups are born with the condition. A minor defect will cause little or no problem, while a more severe defect will cause little or no problem, while a more severe defect will cause signs such as a chronic nasal discharge (that may cause signs such as a chronic nasal discharge (that may include food), poor growth, aspiration pneumonia (from include food), poor growth, aspiration pneumonia (from inhalation of food), or even death.inhalation of food), or even death.

Musculoskeletal Disorders Musculoskeletal Disorders

Intervertebral disk diseaseIntervertebral disk disease Intervertebral disk disease (IVDD) occurs Intervertebral disk disease (IVDD) occurs when the jelly-like inner layer protrudes, or herniates, into the when the jelly-like inner layer protrudes, or herniates, into the vertebral canal and presses on the spinal cord. Compression of the vertebral canal and presses on the spinal cord. Compression of the spinal cord may be minimal (causing mild back or neck pain) to spinal cord may be minimal (causing mild back or neck pain) to severe (causing paralysis, loss of sensation, and lack of bladder and severe (causing paralysis, loss of sensation, and lack of bladder and bowel control) and may be irreversible.bowel control) and may be irreversible.Problems are most commonly seen in the thoracolumbar (lower Problems are most commonly seen in the thoracolumbar (lower back) region of the spine, and are also seen in the cervical (neck) back) region of the spine, and are also seen in the cervical (neck) region. IVDD is seldom a concern in the thoracic (upper back) region. IVDD is seldom a concern in the thoracic (upper back) region, because extra ligaments connect the ribs and help to region, because extra ligaments connect the ribs and help to reinforce the annulus fibrosusreinforce the annulus fibrosus

Patellar luxationPatellar luxation: Slipping kneecap. Should be noticeable puppy vet : Slipping kneecap. Should be noticeable puppy vet check prior to salecheck prior to sale

Nervous System Disorder Nervous System Disorder HydrocephalusHydrocephalus: : an abnormal build-up of cerebrospinal fluid (CSF) in an abnormal build-up of cerebrospinal fluid (CSF) in cavities in the brain (the ventricles). This results in increased pressure on 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 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 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 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 months of life, and in some mild cases the condition is only diagnosed later in life. in life. The types of signs seen with this condition include lack of thriftiness (smaller The types of signs seen with this condition include lack of thriftiness (smaller than littermates, slow to grow), a domed skull (which gradually becomes than littermates, slow to grow), a domed skull (which gradually becomes more pronounced), abnormal movement behaviour (e.g., restlessness, more pronounced), abnormal movement behaviour (e.g., restlessness, aimless walking), problems with vision, and seizures. These pups are very aimless walking), problems with vision, and seizures. These pups are very slow to learn - it may be extremely difficult to housetrain them for example, slow to learn - it may be extremely difficult to housetrain them for example, or they may lose their housetraining.or they may lose their housetraining.

Generally the signs gradually worsen, although by 2 years of age they may Generally the signs gradually worsen, although by 2 years of age they may stabilize. To minimize brain damage, the condition must be recognized and stabilize. To minimize brain damage, the condition must be recognized and appropriate treatment begun early. However, affected animals will likely appropriate treatment begun early. However, affected animals will likely always be slow and have a limited ability to learn.always be slow and have a limited ability to learn.

Skin Disorders Skin Disorders

Dermoid sinusDermoid sinus Dermoid sinus is present from birth, although the Dermoid sinus is present from birth, although the condition is usually not noticed until later. The tracts contain debris condition is usually not noticed until later. The tracts contain debris from the skin - sebum (waxy lubricating substance), dead skin cells, from the skin - sebum (waxy lubricating substance), dead skin cells, and hair - and commonly become infected and painful. If the tract and hair - and commonly become infected and painful. If the tract extends to the spinal canal, infection may cause meningitis or extends to the spinal canal, infection may cause meningitis or myelitis, resulting in various neurologic signs such as local or myelitis, resulting in various neurologic signs such as local or general spinal pain, stiffness, or weakness (depending on the general spinal pain, stiffness, or weakness (depending on the location of the sinus).location of the sinus).

sebaceous adenitissebaceous adenitis This is a perplexing condition in which the This is a perplexing condition in which the sebaceous glands in the skin become inflamed for unknown sebaceous glands in the skin become inflamed for unknown reasons, and are eventually destroyed. These glands normally reasons, and are eventually destroyed. These glands normally produce sebum, a fatty secretion that helps prevent drying of the produce sebum, a fatty secretion that helps prevent drying of the skin.skin.Clinical signs vary with the severity of the conditionClinical signs vary with the severity of the condition

Urinary Disorders Urinary Disorders

Familial kidney diseaseFamilial kidney disease In many of these disorders, the kidneys are In many of these disorders, the kidneys are apparently normal at birth but begin to deteriorate early in life (less apparently normal at birth but begin to deteriorate early in life (less than 1 year of age). While the underlying problem in the kidneys than 1 year of age). While the underlying problem in the kidneys varies between breeds, the end result is the same - kidney failure varies between breeds, the end result is the same - kidney failure for the dog, generally by 5 years of age, although the severity and for the dog, generally by 5 years of age, although the severity and rate of progression vary between breeds and between individual rate of progression vary between breeds and between individual dogs dogs In Shih Tzu the disorder is renal dysplasia In Shih Tzu the disorder is renal dysplasia UrolithiasisUrolithiasis: : a condition in which crystals in the urine combine to a condition in which crystals in the urine combine to

form stones, also called calculi or uroliths. These can be found form stones, also called calculi or uroliths. These can be found anywhere in the urinary tract, where they cause irritation and anywhere in the urinary tract, where they cause irritation and secondary infection. Most end up in the bladder or in the urethra, secondary infection. Most end up in the bladder or in the urethra, where they may cause obstruction, which is a medical where they may cause obstruction, which is a medical emergency. Several different types of uroliths have been emergency. Several different types of uroliths have been identified, with struvite stones (magnesium ammonium identified, with struvite stones (magnesium ammonium phosphate) the most common.phosphate) the most common.

Respiratory Disorders Respiratory Disorders brachycephalic syndromebrachycephalic syndrome Problems associated with this syndrome Problems associated with this syndrome range in severity, with most brachycephalic dogs snuffling and snorting range in severity, with most brachycephalic dogs snuffling and snorting to some degree. Some will have no further difficulties, but many will to some degree. Some will have no further difficulties, but many will have problems such as increasingly noisy breathing, coughing and have problems such as increasingly noisy breathing, coughing and gagging, fainting or collapsing episodes, and a decreased tolerance for gagging, fainting or collapsing episodes, and a decreased tolerance for exercise (ie. they tire easily). Over the long term, this also puts an exercise (ie. they tire easily). Over the long term, this also puts an increased strain on the heart. increased strain on the heart. Overheating is especially dangerous because increased panting (the Overheating is especially dangerous because increased panting (the normal mechanism for cooling in dogs) can cause further swelling and normal mechanism for cooling in dogs) can cause further swelling and narrowing of the already constricted airways, which will increase your narrowing of the already constricted airways, which will increase your dog's anxiety. Excitement, exercise, or warm weather (and especially a dog's anxiety. Excitement, exercise, or warm weather (and especially a combination of these factors) can trigger this vicious cycle. These dogs combination of these factors) can trigger this vicious cycle. These dogs can also have gastrointestinal problems, because of difficulties can also have gastrointestinal problems, because of difficulties coordinating swallowing when they are working so hard at breathing. coordinating swallowing when they are working so hard at breathing. This can result in vomiting gagging because of swallowing so much air, This can result in vomiting gagging because of swallowing so much air, or aspiration pneumonia, because of breathing in saliva or food or aspiration pneumonia, because of breathing in saliva or food particles.They have an increased risk associated with sedation and particles.They have an increased risk associated with sedation and anesthesiaanesthesia

, ., .

In Conclusion In Conclusion Shih Tzus have 19 health concerns Disorders relatively common in this breed are : Exposure Keratopathy syndrome

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

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About your Presenter About your Presenter

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