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GENETIC

CLEARANCES

Parents are tested for genetic health.  This is necessary, because genetic diseases that were once rare are now widespread.

 

Your puppy's parents have been tested for genetic soundness.  The tests have confirmed both sire and dam are able to produce puppies that are not affected by the following severe disorders that affect many golden retrievers.  This means that your puppy will not suffer from these infirmities. 

With recessive genes, a contribution from both the male and the female are necessary for the puppies to be symptomatic for any particular disorder.

 

Below is an explanation of the symptoms. No one can determine simply by looking at a puppy if symptoms of these genetic diseases will appear over time.

Genetic testing was chosen because it is an objective measure.  This means the test results are accurate and not subject to errors of human interpretation or opinion.

Degenerative Myelopathy is an inherited neurologic disorder of dogs.

Inheritance/Transmission:  is autosomal recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease.

Symptoms

  • average age of onset  is approximately nine years of age

  • disease affects the white matter tissue of the spinal cord

  • is the canine equivalent to human amyotrophic lateral sclerosis (Lou Gehrig’s disease)

  • causes gradual muscle atrophy and loss of coordination.  This typically beginning in the hind limbs due to degeneration of the nerves

  • not typically painful for the dog, but will progress until the dog is no longer able to walk

  • gait of an affected dog can be difficult to distinguish from the gait of dogs with hip dysplasia, arthritis in the hind limb joints, or intervertebral disc disease

  • progression of disease later: dogs may become incontinent, both fecal and urinary incontinence

  • may fully lose the ability to walk 6 months to 2 years after the onset of symptoms

Progressive Retinal Atrophy, golden retriever type 1 (GR-PRA1)

is a late-onset inherited eye disease affecting golden retrievers. 

 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease.

Inheritance/Transmission:  
is autosomal recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • clinical symptoms related to retinal degeneration begin showing around 6 to 7 years of age

  • initial clinical signs  involve changes in reflectivity and appearance of the tapetum, which is a structure behind the retina

  • initially have vision loss in dim light (night blindness) and loss of peripheral vision

  • progression leads to thinning of the retinal blood vessels

  • decreased blood flow to the retina.

  • eventually progresses to complete blindness in most affected dogs

Progressive Retinal Atrophy, golden retriever type 2 (GR-PRA2)

is a late-onset inherited eye disease. Its symptoms closely mirror Progressive Retinal Atrophy, golden retriever type 1 (above), except that it is differentiated because it has earlier onset of clinical symptoms and is caused by a mutation of a different gene. 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease.

Inheritance/Transmission:  
is autosomal Recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • clinical symptoms related to retinal degeneration begin showing around 4 to 5 years of age

  • initial clinical signs  involve changes in reflectivity and appearance of the tapetum, which is a structure behind the retina

  • initially have vision loss in dim light (night blindness) and loss of peripheral vision

  • Progression of the disease leads to thinning of the retinal blood vessels

  • decreased blood flow to the retina.

  • eventually progresses to complete blindness in most affected dogs

Progressive Retinal Atrophy, Progressive Rod-Cone Degeneration (PRA-prcd)

is a late onset, inherited eye disease. 

 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease.

Inheritance/Transmission:  
is autosomal Recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • occurs as a result of degeneration of both rod and cone type photoreceptor cells of the retina

  • this affects vision in dim and bright light

  • can first be seen on an electroretinogram around 1.5 years of age for most breeds,

  • most affected golden retrievers will not show signs of vision loss until 5 to 6 years of age or later.

  • initially have vision deficits in dim light (night blindness) and loss of peripheral vision.

  • continued loss of night vision over time

  • visual deficits are seen in bright light over time

  • changes in reflectivity and appearance of the tapetum, which is a structure behind the retina

  • eventually progresses to complete blindness in most dogs

Sensory Ataxic Neuropathy is an inherited neurologic condition affecting Golden Retrievers. 

 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease.

Inheritance/Transmission:  
is mitochondrial. Each pup that is born to a female dog carrying a mutation in the tRNA-Tyr gene is at risk of having the disease.  Male and female dogs must inherit the mutated gene from the mother (not the father) to develop the disease. However, the ratio of mitochondria without the mutation to the number of mitochondria with the mutation is important in determining whether a specific dog will actually develop features of the disease.

Symptoms

  • between 2 to 8 months of age puppies show signs of neurologic disease

  • the disease progresses slowly

  • lack of muscle coordination, abnormal gait and difficulty balancing especially affecting the hind limbs

  • muscle mass appears normal and the condition does not appear to be painful

  • dogs are often humanely euthanized before three years of age

Ichthyosis (golden retriever type) is an inherited skin disorder affecting a large percentage of the Golden Retriever population.  Because it is so widespread, breeding of carriers to each other is not recommended. At least one of the mating pair must not be a carrier.  This is because a contribution from both the male and the female are necessary for the puppies to be symptomatic for this disorder.

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease. 

Inheritance/Transmission:  
is autosomal Recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • skin cornification:  this is an increase in production of dead skin cells in the outer most skin layer (stratum corneum) or an inability of the body to normally shed the cells from this layer

  • large sheets of cells bind and shed together, resulting in fish-like dermal scales seen on skin that can be mild to severe

  • whitish scales gradually give way to blackish-colored scales over time

  • difficult to diagnose without skin biopsies due to close resemblance to allergic dermatitis and other skin conditions

  • in contrast to allergic disease, dogs with ichthyosis do not typically have inflamed or itchy skin, unless a secondary bacterial infection is also present (a relatively common occurrence in these dogs)

  • In moderate to severe cases, management of ichthyosis can be a lifelong, time consuming endeavor best managed with frequent medicated baths and control of secondary infections

  • Unlike the genetic disorders listed above, symptoms of ichthyosis can occasionally be discernible in young puppies.  In many dogs, however, symptoms do not become apparent until the puppy is older

Muscular Dystrophy (golden retriever type) is an early onset, muscular dystrophy disease.  Also known as Duchenne-type muscular dystrophy, Dystrophin muscular dystrophy, DMD, GRMD

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease. 

Inheritance/Transmission:  
is X-Linked Recessive in dogs.  It is a point mutation on the X chromosome, which is the female sex chromosome.*

Female puppies must receive two copies of the mutated gene (one from each parent) to develop the disease


Male puppies only require one copy of the mutated gene from the mother in order to develop disease.   This is why this mutation is more dangerous for male puppies; they more commonly present with symptoms of the disease.

* In nearly every normal mammal, fertilized eggs that produce females have two X chromosomes (XX), whereas fertilized eggs that produce males have an X and a Y chromosome (XY).  These are called sex chromosomes; the others that make up the remaining chromosomal array are called autosomes.

Symptoms

  • affected dogs are unable to produce adequate amounts of a protein important for muscle contraction and relaxation.

  • at 10 weeks of age, affected puppies are noticeably smaller than littermates due to decreased growth associated with the inability to nurse.

  • dogs often need to be hand or bottle fed to prevent starvation

  • around 6 weeks of age, dogs begin to develop a progressively abnormal gait, muscle weakness, excessive drooling, muscle atrophy of the head and trunk

  • At this time, they also develop abnormal extension or flexion of joints and a “roach backed” appearance in the lumbar spine that eventually progresses to a concave flexion

  • dogs may also suffer from aspiration pneumonia and cardiac disease.

  • disease severity: some dogs die soon after birth due to disease complications, whereas others survive for years with only mild symptoms

Osteogenesis Imperfecta is an inherited Collagen disorder affecting dogs.  Also known as Brittle Bone Disease

The sire and dam of this litter do not carry this gene mutation.  Puppies from this litter will not suffer from this disease.


Inheritance/Transmission:  
is an autosomal Dominant point mutation.  This is very dangerous.  Each pup that is born to a parent carrying one copy of the mutation has a 50% chance of inheriting one copy of this gene mutation and suffering terribly from this disease.

Symptoms

  • occurs as a result of a defect is in the way collagen is made.  (collagen is an important component of bone)

  • bones of affected dogs are thinner than normal, fracture easily and do not heal properly

  • affected puppies may die shortly after birth and be smaller than littermates

  • puppies with this disorder typically present between 3 to 4 weeks of age with pain, lameness and fractures, loose joints and brittle teeth

  • due of the severity of the disease, pups with Osteogenesis Imperfecta are usually euthanized by 3 months of age

Dystrophic Epidermolysis Bullosa is a hereditary skin disease. Clinical signs are present at birth. 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease. 

Inheritance/Transmission:  
is autosomal Recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • fragile skin that is easily damaged from rubbing or trauma resulting in blisters, ulcers and scarring of the skin.

  • external blisters:  can develop on the face, foot pads, genital areas and ears

  • internal blisters and ulcers:  inside the mouth and in the esophagus

  • ulcerations of the skin and mucous membranes are painful and can become infected

  • blistering of the skin tends to cease at approx 8 months of age

  • ulcers of the mouth and esophagus persist into adulthood

  • difficulty eating adequate amounts of nutritional food necessary stunts proper growth

Neuronal Ceroid Lipofuscinosis is an inherited lysosomal storage disease. 

The sire and dam of this litter are unaffected by this disorder.  Puppies from this litter will not suffer from this disease. 

Inheritance/Transmission:  
is autosomal Recessive meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease.

Symptoms

  • affected dogs lack adequate activity of a specific Enzyme necessary for normal cellular metabolism

  • results in abnormal accumulation of waste compounds primarily in the cells of the nervous system, leading to a range of neurological symptoms.

  • affected dogs usually present around 13 months of age with progressive neurological disease beginning with loss of coordination, balance issues, or difficulty climbing stairs. These may be more pronounced when excited

  • progresses to include severe incoordination, anxiety, agitation, persistent circling or pacing, loss of response to learned commands or behaviors, snapping at air (called “fly-biting”), blindness, aggression, and seizures

  • Affected dogs typically die or are humanely euthanized by 3 years of age

Multidrug Resistance 1 causes a defect in a protein that is responsible for protecting the brain by transporting potentially harmful chemicals away from the brain.  Also known as Ivermectin sensitivity, MDR1 gene defect, Multidrug sensitivity, MDR1

Some Collie anomolies were detected in Nova Scotia Duck Tolling Retrievers, a breed that is closely related to Golden Retrievers.  Of concern is the MDR1 gene mutation.  Dogs carrying this gene can suffer serious neurological harm and even die if certain types of commonly used drugs are administered to them. Given the potential lethality of this disorder, testing for this prior to breeding is very important. 

The sire and dam of this litter do not carry this gene mutation.  Puppies from this litter will not suffer from this disease.

Inheritance/Transmission:  
Autosomal Incomplete Dominant.  This is very dangerous.  Puppies only need to inherit one copy of the mutated gene to be at an increased risk of developing the disease.

Symptoms

  • as a result of the accumulation of toxins, the dog can show neurological symptoms, such as seizures, ataxia, tremors, excess salivation, anorexia, and blindness, to coma and even death.

  • inability to metabolize specific drugs is defective; certain drugs can be lethal even at low doses.  Some of these drugs are very commonly used.

  • causes dysfunction of P-glycoprotein, which is responsible for removing certain drugs and toxins from the body

  • clinical signs are most commonly associated with distribution of the drug in the central nervous system

  • carrier dogs can also experience drug sensitivities and dosages need to be adjusted accordingly


Drugs known to cause harm in dogs carrying the MDR1 mutated gene


Paracitides

  • ivermectin (aka Ivomec® and Heartgard®), is used to prevent heartworm and to treat various other parasite-related conditions such as demodectic and sarcoptic mange, and ear mites

  • milbemycin, is used to fight worms, ticks and fleas

  • moxidectin, is used to prevent or control heartworm and intestinal worms

  • selamectin (aka Stronghold®/Revolution®), is an antiparasitic topical once-a-month pet medicine, helps treat and prevent heartworms, fleas, ear mites, sarcoptic mange and certain types of ticks

  • emodepside:  is used in combination with praziquantel (aka Profender®), treats several types of intestinal worms


Antibiotics

  • erythromycin, an antibiotic used to treat a wide variety of bacterial infections.

  • rifampin, is an antibiotic used to treat bacterial infections caused by Rhodococcus, Mycobacteria and Staphylococci.  Rifampin has antifungal activity when combined with other antifungal agents and may be used to treat infections such as histoplasmosis or aspergillosis


Others

  • acepromazine, is a commonly used tranquilizer/sedative in dogs, cats, horses, and other animals

  • butorphanol (aka  as Torbutrol®),  is used for for pain relief and for coughing.

  • loperamide (aka Immodium), commonly used to treat diarrhea, gastrointestinal upset, inflammatory bowel disease

  • digoxin (heart drug)

  • doxorubicin (aka Adriamycin, Rubex),  is a chemotherapy drug

  • vinblastine, is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug

  • vincristine (aka Oncovin among others), is a chemotherapy medication used to treat a number of types of cancers


The following drugs may also cause problems:

  • Ondansetron, Domperidone, Paclitaxel, Mitoxantrone, Etoposide, Quinidine, Morphine