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DNA Tests - page 2

[Atopic Dermattis] [CMO - Craniomandibular Osteopathy]
[Cryptorchisism] [Epilespy]  [GCL - Globoid Cell Leukodystropy]
[Heart Disease] [Hernia] [Luxated Patella] [Pigmentary Glaucoma]
[Portal Systemic Shunt] [PRA - Progressive Retinal Atropthy]
[vWD - von Willebrands Disease]

Compiled by Jerrie E. Wolfe jerrie@rose-croft.dk 

 

ATOPIC DERMATITIS (Skin Allergies, Allergic Inhalant Dermatitis, Food Allergies)

This can cover many problems from a common flea allergy to complicated autoimmune diseases. It can be defined as the inherited ability to form reaginic antibodies against environmental allergens and to express clinical allergic signs to these allergens. Therefore, it is a condition resulting from a disorder in the immune system. Proper diagnosis will allow treatment of the specific skin problems in individual dogs. Food allergies are common. The main clinical sign is itching, licking or chewing of the feet and groin area and rubbing and scratching the face, ears and the area in front of the tail. Additional signs include reversed sneezing, discoloration of the coat, red crusty eyes, reddening of the skin, papules and hair loss. Depending on the part of the United States, these symptoms can become seasonal because the most common allergens include: dander, pollens of grasses, weeds, trees, house dust, and molds. It is seen in both sexes, but it is more common in females. Age of Onset - In 75% of cases the disease appears between 1 and 3 years of age. 

Further reading on the web - 

WHWTCA

Priory Lodge Education Ltd. 

Flea Allergy Dermatitis  

Skin and Allergy Problems in Dogs 

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 CRANIOMANDIBULAR OSTEOPATHY - CMO (Syn: Lion Jaw)

A non-cancerous growth of bone on the lower jaw (ramus or point of the chin) or over the angle of the mandible and tympanic bulla. It is usually on both sides of the head, but this is not always so. The bone is dense and hard with a rough surface that can be usually be felt. CMO is painful; the site will feel warm to the touch and inflamed. It is usually first noticed when a puppy shows discomfort when chewing or having its head or mouth examined, becomes unwilling to eat, has a fever and is lethargic. However, silent cases (no pain) have been reported. An acutely affected puppy may be unable to open his mouth but mild cases may be misdiagnosed as teething problems or virus symptoms. Age of Onset - Generally it occurs between 4 and 7 months of age, but can be as early as 3 to 4 weeks - usually not after 9 months. An accurate diagnosis requires x-rays. The disease is usually controlled with the use of steroids. The disease is self-limiting and fortunately, as the dog matures, the abnormal bony growth disappears and is often undetectable in the adult dog, even by radiography. 

There is the possibility of research in the near future to find the DNA (gene) marker, which will enable breeders to clear their lines of this disease. 

Further reading on the web - WHWTCA 

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CRYPTORCHIDISM (Un-descended Testicles)

This disorder is the result of failure of the testes (one or both) to descend into the scrotum through the inguinal canal. Dogs that are cryptorchid suffer a higher than normal risk of testicular cancer. It is strongly recommended that affected dogs be neutered and never used for breeding. This disorder becomes apparent at about 12 weeks. The large majority of males have their testicles descended by this age. Also be aware that there is a theory that this condition is carried as a sex-linked gene and the dams play a part in producing this fault. If that is true, and the females don't have the "equipment" to prove they are actually carriers, they can produce affected dogs in your line. 

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 EPILEPSY (Seizures)

Seizures can indicate the disease Epilepsy or they may be the result of other diseases such as low blood sugar, brain tumor, heat stroke, poison, nutritional deficiency, distemper and liver shunt. Classic or idiopathic (meaning "of unknown cause") epilepsy is characterized by recurrent seizures with no active underlying disease process occurring in the brain. This form of epilepsy is not usually seen until a dog is mature, usually between three and five years of age. In a typical seizure, the dog will salivate excessively. There is usually dilation of the pupils and stiffening of the limbs. The dog may arch its back and paddle its legs. Frequently, the dog's temperature will spike up three to five degrees. Urination or defecation may accompany or follow the episode. Seizures usually last only a minute or two, but severely affected dogs may have longer and more frequent episodes. Seizures should be considered serious and your veterinarian should be consulted. 

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 GCL - GLOBOID CELL LEUKODYSTROPHY (Syn: Krabbe's Disease)

Globoid Cell Leukodystrophy is a degenerative disease of the white matter of the brain and spinal cord. Segmental degeneration of some peripheral nerves may also occur. It is the result of a genetic deficiency of an enzyme (Galactocerebroside B-Galactosidase) needed to break down certain fats in the spinal cord and brain. Early signs can begin as early as 4 weeks with lack of coordination, weakness, stumbling, loss of control of the hindquarters, and tail tremors may be observed along with reverse arching on the back. Then the dog will develop a wide stance, further lack of coordination, and posterior or total limb paralysis. The dog may become blind or fail to recognize familiar individuals. Usual onset takes place before 5 to 6 months of age. There is no cure and is always fatal. However, Dr. David Wenger of Philadelphia, PA has found the DNA (gene) marker for both Cairns and Westies, while doing research for this condition in children. Dr. Wenger's DNA test will enable breeders to identify carriers and it is now possible to eliminate this disease from the breed. 

Further reading on the web and how to contact Dr. Wenger go to the WHWTCA page. 

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HEART DISEASES

Heart murmurs in puppies may or may not indicate heart disease later in a pup's life. Many murmurs disappear as the puppy ages. A physical exam at 6-8 weeks of age should be done on all puppies. I recommended that a new owner have a thorough exam done within 72 hours of acquiring the puppy. Most breeders will require that you take your puppy to your own vet as soon as possible for these examinations.  

Cardiomyopathy is a general term for heart problems. It usually means that for some reason the heart muscles have become weakened and do not function properly. There is no test to determine if a dog is going to develop a heart problem, only tests to diagnose them once they occur. If a dog does have a heart problem you may find that it is only able to exercise for short periods of time before becoming tired, or that even while resting its breathing is labored. 

Some heart problems appear late in a dog's life and are attributed to the age of the dog. 

Further reading on the web: OFA - Heart Registry 

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HERNIA

Hernias have two distinctions: inguinal, in the groin area and can affect both sides or just one, or umbilical, at the navel. A hernia is a protrusion of abdominal contents: an organ, fluids and fat, through either the unclosed umbilical opening or an abnormally large inguinal ring forming a skin covered sac. Normally, the inguinal ring forms a passageway for the vaginal process, through which pass the spermatic cord in the male and the round ligament in the female, and the genitofemoral nerve, artery, and veins in both sexes. Hernias need to be watched carefully. If the protruding tissue is trapped in the sac, then the limb that the arteries feed will be cut off of its blood supply. Scrotal hernias in males are a specific type of inguinal hernias. Hernias usually appear before 12 weeks old and both sexes are effected equally. Surgical correction is indicated only if the hernia is large and is not self-correcting. Surgical corrections of inguinal hernias are a disqualification according to AKC Rules and Regulations.  

Acquired inguinal hernias also occur, usually in the middle-aged unspayed bitch. 

The mode of inheritance has not been determined. A study done in swine showed that the frequency of inguinal hernia increased from 1.7% to 90% in 6 generations, so the disorder has the potential to develop into a severe problem in a line, kennel or breed.  

Further reading on the web - WHWTCA 

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LUXATED PATELLA (Syn: Slipped Patella, Slipped Stifle, Slipped kneecaps)

Luxating patellas is the most common disease in the Cairn Terrier. It is a disorder where the patella (kneecap) slips out of the trochlear groove usually to the inside of the leg. It may be on one or both sides and mainly affects small and miniature breeds. It may cause severe pain when the dogs runs and plays. The dog may sometimes yelp and "skip" in the rear. It is sometime seen as a "bunny hop" in the rear, with the dog showing no other signs of the disease. The disorder may seem minor, and the kneecap can be pushed back into place, but in the most cases luxation recurs repeatedly. The disorder can also be very severe, with permanently fully flexed hocks and stifles with the dog moving the best it can, yet apparently indifferent to the deformity. The disease can be difficult to study, since a genetic susceptibility must be present in combination with factor such as running, jumping or sudden turns that causes the kneecap to slip out of place. In some cases, the trochlear ridges are so low or eroded or the patella is so loose, it slips free with little or no effort.  

This disease occurs in 4 grades: Grade 1 - no clinical signs, Grade ll - may or may not show clinical signs, Grade lll - and Grade lV (most severe) show clinical signs and corrective surgery may be necessary. Age of Onset - usually occurs at 4 - 5 months of age but may occur earlier or later.    

Further reading on the web - WHWTCA  

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PIGMENTARY GLAUCOMA

This is a condition where the pressure of the fluid in the eye increases until the sight is gone in that eye. If it strikes one eye, the other eye is likely also to be affected. Glaucoma is one of the leading causes of blindness in dogs. Any underlying problem that increases the fluid pressure inside the eye is the culprit; most of the time this is due to inadequate drainage of fluid from the eye (as opposed to overproduction of fluid). In some breeds such as the Samoyed and Beagle glaucoma has been found to be hereditary. Strong evidence now points to Inherited Primary Glaucoma in the Welsh Terrier.  

Signs of glaucoma include reddened conjunctiva tissue (red eye), weeping, light sensitivity, or even enlargement of the eye. As pressure increases, the pupil can become dilated and the cornea cloudy. In the earliest stages, the owner of the dog may notice that the eyes have a glassy look or seem to be dilated more than normal for the amount of light available. It is at this point that a veterinarian who can measure the pressure in the eye must evaluate the eye. Early diagnosis is critical to save the vision of the dog, and involves treating the underlying causes of the increased pressure if at all possible.  

As the pressure in the eye, also known as the intraocular pressure or IOP, rises above normal the lens may be torn from its attachments and become loose within the eye. This can cause serious problems including damage to the cornea. 

Diagnosis and classification of pigmentary glaucoma requires measurement of the IOP (tonometry) and examination of the iridocorneal angle (gonioscopy). Neither of these tests are part of a routine screening exam for certification. In the Cairn Terrier, the obstruction of the outflow pathways for the aqueous humor occurs as a result of proliferation of pigmented cells (melanocytes) within the iridocorneal angle and sclera. The disease is progressive and often results in blindness. To date this disease has only been found in Cairn Terriers. 

CERF examinations may alert owners to the onset of this disease and the need for more extensive examination. In some cases measures can be taken to ease pain and prolong sight. 

Further reading on the web: 

CERF - Canine Eye Registration Foundation 

Veterinary Opthamology Information Center 

The American Society of Veterinary Ophthalmology 

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PORTAL SYSTEMIC SHUNT (Syn: Liver Shunt, PSS)

Portosystemic shunt is an abnormal flow of blood between the portal vein and a systemic vein that shunts blood away from the liver into the systemic circulation. There are two types of shunt - Intra-Hepatic and Extra-Hepatic. Most dogs will be diagnosed with port-systemic shunts under one year of age, but dogs as old as eight have been diagnosed with the condition. Animals are usually stunted, thin, depressed, have trouble gaining weight, and are usually characterized by the owners as chronic "poor doers". In most affected dogs there will be some degree of behavioral signs ranging from listlessness, apathy, or depression to more severe signs of circling, head pressing, stupor, drooling, blindness, or convulsions, some leading to coma. These behavioral changes are due to an accumulation of toxins (especially ammonia) that affect the brain causing a condition called Hepatic Encephalopathy. These toxins are most abundant in the blood stream following the dog eating, especially a high protein meal, & may remain high for hours afterward. Not all dogs with the shunt will show this meal associated behavioral change, but in 25% of the affected dogs that do, the diagnosis becomes clearer. A high percent of affected animals show intolerance to anesthetics or tranquilizers, & will show increased recovery times following use of these products. Even anti-convulsants used to control seizures may be potentially dangerous if allowed to concentrate in a dog with functional shunt. Approximately 75% of affected individuals will show digestive system symptoms including poor appetite, vomiting, drooling, diarrhea, or occasionally deranged appetite (eating paper, etc.). Urinary system symptoms may include increased thirst and urination, & in a majority of Portosystemic shunt cases, there will be crystals or stones formed in the urinary tract. These crystals will be either uric acid or ammonium urate (ammonium biurate or thorn apple crystals.). There can be bladder stones formed or crystals may be noted on the hair around the prepuce or vulva. 

At the present time, Hepatic Portosystemic shunts are considered to be UNQUESTIONABLY genetic by some of the leading canine experts, but the mode has not been identified at the present time. Genetic disorders in dogs can spread relatively rapidly if a dog, whether affected or a carrier, is a well-respected animal in either conformation or ability, and is used extensively for breeding. This is especially true in the case of the male that can produce hundreds of offspring during his breeding life. 

The Yorkshire Terrier Club of America Foundation, Inc. is currently funding research into the genetic nature of the problem. 

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PRA - PROGRESSIVE RETINAL ATROPHY

Progressive retinal atrophy, or PRA as it is frequently termed, is a long recognized hereditary, blinding disorder. The first modern description of this problem was in Gordon Setters in Europe, in the early years of the twentieth century, but since then PRA has been recognized in most purebred dogs. PRA is a disease of the retina. This tissue, located inside the back of the eye, contains specialized cells called photoreceptors that absorb the light focused on them by the eye's lens, and converts that light, through a series of chemical reactions into electrical nerve signals. The nerve signals from the retina are passed by the optic nerve to the brain where they are perceived as vision. The retinal photoreceptors are specialized into rods, for vision in dim light (night vision), and cones for vision in bright light (day and color vision). PRA usually affects the rods initially, and then cones in later stages of the disease.  

In all canine breeds PRA has certain common features. Early in the disease, affected dogs are night blind, lacking the ability to adjust their vision to dim light; later their daytime vision also fails. As their vision deteriorates, affected dogs will adapt to their handicap as long as their environment remains constant, and they are not faced with situations requiring excellent vision. At the same time the pupils of their eyes become increasingly dilated, causing a noticeable "shine" to their eyes; and the lens of their eyes may become cloudy, or opaque, resulting in a cataract. 

In the later stage of this disease the dog is totally blind at night and daylight vision is impaired leading to complete blindness. There is no cure. An annual CERF examination, by a qualified ophthalmologist, is recommended for breeding stock. This is an autosomal recessive trait. Neither affected animals nor their sires and dams should be used for breeding. Both parents will be carriers. Hopefully research will be done to find a DNA (gene) marker (like in GCL) so that this disease can be controlled. 

Further reading on the web: 

CERF - Canine Eye Registration Foundation 

Veterinary Opthamology Information Center 

The American Society of Veterinary Ophthalmology 

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von WILLEBRAND'S DISEASE - vWD

Von Willebrand's Disease is the name given to a group of similar inherited bleeding disorders that occur in humans, pigs, dogs and rabbits. vWD is usually less clinically severe than hemophilia and is inherited as an autosomal trait. This means that it can be transmitted equally by and to both sexes. Carriers are asymptomatic but affected dogs may exhibit any of the following symptoms: excessive bleeding when the nails are cut too short, severe bleeding during surgery, bleeding from the nose or gums, particularly during teething, bleeding from the vagina or penis, hematomas on the surface of the body, limbs or head, internal bleeding, lameness from bleeding into the joints, stillbirths or neonatal deaths with evidence of hemorrhage at autopsy, chronically infected and bloody ears, prolonged bleeding during the heat cycle or after whelping, bleeding in stools or urine. 

In addition to the inherited variety, an acquired version has also been reported in humans as well as dogs, associated with thyroid hormone deficiency (hypothyroidism). 

According to the study noted below, 71% of the hypothyroid dogs had a decreased concentration of plasma von Willebrand's factor/ antigen compared with only 7% of clinically normal dogs. Animals, which had thyroid levels intermediate between normal and abnormal frequently, had von Willebrand's factor/antigen levels in the same range. Also, of 54 dog breeds recognized to have von Willebrand's disease, 42 also have a family tendency toward hypothyroidism. It is therefore difficult in those cases to determine whether the von Willebrand's disease was congenital or acquired.  

The significance of this association is most apparent during treatment. Acquired von Willebrand's disease caused by hypothyroidism is best treated with thyroid hormone (thyroxine) supplementation. It is frequently prescribed for inherited von Willebrand's disease but is not always successful in these cases.  

[Some material abstracted from Avgeris, S; et al: Plasma von Willebrand's factor concentration and thyroid function in dogs. Journal of the American Veterinary Medical Association, 1990; 196(6): 921-924.] 

There is presently research being done at Michigan State University to identify the DNA (gene) marker. Many Cairn breeders (like myself) are participating in this research. It is expected the marker will be found within one year. When the marker is available, breeders will be able to identify carriers, control the disease, and eliminate it from the Cairn breed. 

DNA Studies in Doberman von Willebrand's Disease 

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This article is a brief summary and therefore incomplete.

Disclaimer: The reader may download one copy for personal use, but any further dissemination of the article needs to be with express permission of the author.

More extensive information about genetic anomalies of the Cairn Terrier is discussed in the CTCA's Genetic Manual, which is available from the Foundation at a cost of $15. Plus $5. Postage. Anyone wanting to buy the manual should contact Clare Redditt - cairnacre@epix.net 

Ackerman, L: Owner's Guide to Dog Health. T.F.H. Publications, Nepture City, New Jersey, 1995.
Ackerman, L: Guide to Skin and Haircoat Problems in Dogs. Alpine Publications, Loveland, Colorado, 1994

Willis, Malcolm B. "Genetics of the Dog", Howell Book House, New York. 


Further reading on the web: 

Eliminating Genetic Diseases in Dogs: A Buyer's Perspective 

Knowing What You're In For 

Canine Consumer Report, A Guide to Hereditary and Congenital Diseases in Dogs  

The Immune System and Disease Resistance W.Jean Dodds, DVM 

The World-Wide Web Virtual Library: Veterinary Medicine (Biosciences) 

Veterinary Specialties 

The Dog Genome Project 

Information about Genetic Disorders in Dogs 

The Institute for Genetic Disease Control in Animals 

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This page was last  March 30, 2002

 

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