Health and Hereditary Diseases

It is a fact that every dog of every breed is susceptible to and carries the genes for certain diseases.

Golden Retrievers, like all breeds, have a limited gene pool that descends from a fairly small number of ancestral dogs. It has been estimated that 99 percent of present day Golden Retrievers can trace their family roots back to only three breeding pairs. Careless breeding increases the incidence of health problems, but even carefully bred dogs can be affected.

SKELETAL DISORDERS

Hereditary joint problems are prevalent in many breeds, with elbow and hip dysplasia being the most widespread. Golden Retrievers have both. Although a dog is more likely to be affected if its ancestors were affected, there are no guarantees.

Hip Dysplasia
Hip dysplasia (HD) occurs when the ball of the femur bone does not fit properly into the socket of the pelvic bone. The fit is affected by both the depth and shape of the socket and the laxity of the joint. When pressure is put on the joint, such as when the dog walks or runs, the combination of a shallow socket and joint laxity allows the ball of the femur to pop in and out of the socket. This movement further deteriorates the socket’s rim, worsening the condition and advancing the disease. Early diagnosis and treatment are important. It’s a good idea to have your dog’s hips evaluated at an early age so that you can take measures to prevent irreparable joint changes, which may include surgery or administration of certain medications.

HD can become progressively more crippling and painful. Whereas mild cases may not need specific treatment, more severe cases may need timely surgery in order to prevent crippling disability. If the condition is detected in a young dog before damage has been done, a procedure known as a triple pelvic osteotomy (TPO) can be performed. In a TPO, the dog’s hip socket is surgically altered to allow the femur head to fit better into the socket. Older dogs or dogs with advanced dysplasia are better candidates for a total hip replacement, in which the ball of the femur is replaced with a metallic ball, and the socket is replaced with a Teflon cup. A third procedure, which is less effective in large dogs, is to remove the head of the femur. This procedure may be a more reasonable choice for financial reasons in an older dog that needs only to be comfortable walking around the house.

Elbow Dysplasia
Elbow dysplasia encompasses several problems, all of which eventually lead to degenerative joint disease of the elbow. In Goldens, fragmented coronoid process (FCP) is the most common cause.

The medial coronoid process of the ulna is a thin finger of bone that is normally attached to the head of the ulna, one of the long bones of the forearm. It works to stabilize the elbow by fitting snugly in a notch in the humerus (upper arm) where it hinges with the ulna. In some dogs, the coronoid process never attaches properly to the ulna or becomes fragmented, allowing the dog’s elbow to shift from side to side when the dog places weight upon it. The fragments break loose, float around, and irritate the elbow.

Symptoms, which can appear in dogs as young as seven months of age, include swelling, pain, and lameness originating in the elbow joint. Affected dogs have a decreased range of elbow motion. Typically, treatment involves surgically removing the loose fragments.

Osteochondrosis Dissecans
Osteochondrosis dissecans (OCD) is lameness that occurs when a flap of cartilage becomes detached from the bone. Lameness is progressive and often starts around seven to ten months of age. The most common site is in one or both shoulders, but almost any joint can be affected. Often, absolute rest for several weeks can help, but sometimes rest can actually make lameness worst. Symptoms seem better with mild exercise, and worse with heavy exercise. Surgical repair is usually the preferred method of treatment.

Panosteitis
Panosteitis is an inflammation of the long bones resulting in lameness, which often shifts from leg to leg. “Pano” is most common in growing dogs of large breeds such as Goldens. Symptoms may appear suddenly, usually between five and ten months of age. The exact cause is not known, but the prognosis for a full recovery is excellent. Treatment consists of limiting exercise and administering analgesics.

OCULAR DISORDERS

Goldens that will be used for breeding should be checked by a veterinary ophthalmologist and cleared by the Canine Eye Registration Foundation (CERF). Certification is good for only a year because of the progressive nature of most eye diseases.

Juvenile Cataracts
Many dogs get cataracts as they age, but in some Goldens, cataracts can appear earlier than seven years of age. These cataracts, called juvenile cataracts, are usually hereditary. Although juvenile cataracts aren’t usually extensive and don’t interfere with the dog’s vision, they do tend to get progressively worse with age. In severe cases, the lens can be removed and replaced with a prosthetic lens.

Retinal Dysplasia
Retinal Dysplasia (RD) is a defect of the retina in which two of the retinal layers fail to grow together properly during development. As a congenital condition, it neither gets better nor worse with age, and can be detected in young puppies. Sometimes RD is mild so that the usually smooth retinal layer has “retinal folds.” In more severe cases the affected area will be much larger, resulting in “geographic” RD. At its worst, the two layers remain separated throughout the eye and retinal detachment occurs. The mode of inheritance is not known, and in some cases, prenatal infections can play a role.

Central Progressive Retinal Atrophy
In Central Progressive Retinal Atrophy (or CPRA), the light-sensitive cells of the center part of the retina gradually deteriorate. As more of these cells are lost, the dog’s vision gets gradually worse, ultimately resulting in blindness. Researchers have recently identified vitamin E as playing an important role in this disorder. Vitamin E is an antioxidant that helps protect the retinal cells from damage caused by light. Affected dogs don’t seem to retain sufficient quantities of vitamin E in their system after they ingest it. Experimental studies suggest that by supplementing these dogs with vitamin E, sufficient levels of vitamin E can be maintained in the dog’s system to protect the retina and prevent CPRA. Careful screening is still needed for effective prevention since the problem must be caught early in order to stop progression of the disease.

Lid and Lash Disorders
The most common eye disorders in all dogs are probably those of the lids and lashes. Dogs with deep-set or diamond-shaped eyes are more likely to have entropion, in which the eyelids turn in toward the eye. This allows the lashes to rub against, irritate, and even damage the eye. In extropion, the lid is turned outward, leading to drying and irritation of the eye and surrounding tissues. In trichiasis and distichiasis, the eyelashes are directed in toward the eye, irritating it. In many of these disorders, surgery may be needed for dog’s health and comfort.

CIRCULATORY SYSTEM DISORDERS

Compared to many other breeds, Goldens have healthy circulatory systems, but they, too, have their problems. All breeding dogs should be examined by a veterinary cardiologist, and even nonbreeding dogs should be screened by having a veterinarian listen to the heart for a murmur. Heart murmurs indicate a turbulent blood flow, usually the result of blood being forced through a faulty heart valve or through too small of an opening. Dogs with murmurs should be seen by a veterinary cardiologist for an ultrasound of the heart.

Subvalvular Aortic Stenosis
Subvalvular aortic stenosis (SAS) is one of the most common congenital heart defects in dogs, and one of the breeds that it is seen most often in is the Golden Retriever. In SAS, the opening between the heart’s left ventricle and aorta is abnormally narrow, obstructing the blood flow. Severe cases can cause death by three years of age. Less severe cases may not exhibit noticeable signs, although some dogs may be weak and collapse when exercising. Screening is done by listening to the heart.

An affected dog should not be bred. Current evidence shows that SAS may be hereditary. Some dogs with this gene may have little, if any symptoms of SAS but can still pass it on. Such dogs are known as “silent” cases. SAS can lead to early or even sudden death and is not a disease to risk. For serious cases, open-heart surgery is the best treatment, but it is expensive and risky.

Dilated Cardiomyopathy
Dilated Cardiomyopathy (DCM) is a progressive disease in which the muscles of the heart lose their contractibility. The heart compensates by several mechanisms that ultimately produce an enlarged heart with thin muscle walls. Symptoms include coughing, labored or rapid breathing, weight loss, general debilitation, abdominal distention, cold extremities, fainting episodes, and heart murmur. Often, symptoms appear to have developed quite suddenly. This is especially true in dogs that are normally not very active, but, in fact, the condition has been developing slowly. Only when the failing heart can no longer compensate, do the symptoms surface.

Cardiomyopathy is one of the most common serious acquired cardiac diseases in dogs. When considered as a percentage, Goldens rank fourteenth out of all breeds. In most breeds, there is no prevention and no cure for cardiomyopathy, and dogs eventually die of congestive heart failure or severe abnormal beating.

ENDOCRINE SYSTEM DISORDERS

The endocrine system includes several glands that secrete hormones, chemicals that travel via the bloodstream to cells and tissues in the body, regulating their function. Endocrine system disorders include diabetes, Cushing’s syndrome, Addison’s disease, and others, but the main endocrine disorder diagnosed in Golden Retrievers is hypothyroidism.

Hypothyroidism
The thyroid glands are located near the dog’s larynx in the neck and produces calcitonin, a hormone necessary for calcium metabolism, and T4, a hormone that regulates metabolism and is essential for the normal function of many of the body’s organs and systems. In some dogs, the thyroid gland doesn’t make enough hormones, usually because the thyroid gland degenerates from being attacked by the body’s own immune system, or for other, unknown reasons.

Hypothyroidism is the most commonly seen endocrine problem in Goldens and is also more often seen in Goldens than any other breed. It is diagnosed more often in spayed and neutered dogs.

Clinical signs include hair loss on the flanks, tail, or behind the ears; darkened and thickened skin, sometimes with scaling; weight gain, lethargy, intolerance to cold, slowed heart rate, and infertility. However, don’t assume your dog has this condition based on clinical signs alone. There are several blood tests available to give a definitive diagnosis.

Treatment is with daily medication and progress monitored with retesting in about two months.

CANCERS

Cancers occur fairly frequently in all breeds of dogs. Some occur more frequently in certain breeds than others.

Mast Cell Tumors
Skin cancer is the most common type of cancer in dogs, and mast cell tumors are among the most common skin cancers. Golden Retrievers appear to have an increased risk of mast cell tumors compared to other breeds. Although they can appear at any age, they are most commonly diagnosed at around 8 or 9 years of age, and are also diagnosed more often in neutered and spayed dogs.

Mast cells tumors can appear in many parts of the body, most often the spleen, liver, bone marrow, and skin. Those of the skin are most easily discovered by the owners. A mast cell tumor most often appears as a small, firm, raised mass, usually with well-defined borders. It may or may not be reddened, hairless, and ulcerated. Sometimes a mast cell tumor will continue to grow quite large, whereas others may become an area of thickened skin. It is nearly impossible to diagnose a mast cell tumor from appearance alone.

Diagnosis begins with a biopsy, which can usually be done as a fine needle aspiration. Cancerous cells are evaluated from Grade 0 to Grade IV according to how well the cells are formed. Grade 0 has the best prognosis while IV has the worst.
Treatment depends upon the tumor grade and other test results. A low-grade tumor can often be effectively treated by removing tissue around and beneath the tumor. Because it is not uncommon for cancerous cells to be left behind, the remaining cells can be removed or destroyed with radiation treatments.

With higher-grade tumors, chemotherapy may be administered. Prednisone is the most effective drug, and although it has several unfortunate side effects, its benefits usually far outweigh them.

Ultimately, the prognosis depends upon the grade of the tumor and the presence of tumors in other parts of the body.

Hemangiosarcoma
Hemangiosarcoma is a malignant cancer of the circulatory system. Most often, this cancer occurs as a tumor on the spleen or heart although it may sometimes first appear as a skin growth. As the tumor grows, internal bleeding may occur. Affected dogs may suddenly appear disoriented and collapse. They may exhibit extreme thirst and have very pale gums. Bleeding from the tumors can result in a bloated, fluid-filled abdomen.

If the tumor is on the skin, it can be surgically removed and it’s possible that the dog will make a full recovery as long as the cancer has not already spread. If the tumor is on the spleen, the spleen can be removed. Even small tumors near the heart can sometimes be removed. Unfortunately, despite all treatments available, most dogs with hemangiosarcoma die within a couple of months after diagnosis either because of bleeding that cannot be stopped or cancer that has spread to other organs.

In a recent study, Golden Retrievers accounted for more cases of hemangiosarcoma of the heart than any other breed. Spayed females had a much higher incidence than non-spayed ones.

Lymphosarcoma
One of the more commonly seen cancers in dogs, lymphosarcoma affects the blood and lymph systems. Symptoms include swelling of the lymph nodes, especially those of the lower neck area and behind the dog’s “knees.” Chemotherapy can extend the life of many affected dogs.

Osteosarcoma
Osteosarcoma or bone cancer occurs more frequently in large-breed dogs, including Golden Retrievers. Owners are usually faced with the decision of amputation. The decision must be made quickly as to prevent the spread to other parts of the body. Dogs adjust to the loss of a limb fairly easily, but factors such as age, weight, arthritis and other joint problems factor into how well the dog can cope with only three legs. The possibility of phantom limb pain can be reduced by having the vet numb the leg for the day before it is to be removed. Even with the best of therapy, survival time for dogs with osteosarcoma may be short.

GOLDEN RETRIEVER MUSCULAR DYSTROPHY (GRMD)

Although a rare disorder, GRMD, as the name implies is recognized more often in Goldens than in other breeds. This disorder is considered to be similar to Duchenne Muscular Dystrophy in humans. Muscle tissues from affected dogs have reduced levels of dystrophin-associated proteins. Affected dogs show signs by eight to ten weeks of age, which include general muscle weakness, crouched posture, shuffling gait, splayed feet, and swallowing and chewing difficulty. The condition rapidly worsens between three and six months of age and is ultimately fatal. Gene therapies may one day be available for treatment.

Most affected dogs are males although females can be carriers. Genetic tests can now identify dogs as clear, carriers, or affected.