Information by Boxerworld Webite
What is genetic disease?
A genetic disorder is one in which an abnormality in the genetic
make-up of the individual plays a significant role in causing a disease or condition. While some disorders can occur as the
result of spontaneous mutation, most genetic disorders are inherited. These diseases are heart-breaking, they can impact severely
on the quality and length of life of the dog - who is generally a well-loved family member by the time the condition
The frequency of inherited conditions can be greatly reduced through good breeding practices. For this
to occur, we need to know how the disease is inherited, how to identify the condition as early as possible, and ways to recognize
carriers of the disease who are not clinically affected. Where the health testing are available, it's important that
all breeding stock are screened. Animals found to be affected or carriers of a disease should not used for breeding.
Genetic Diseases in Boxers
stenosis/sub-aortic stenosis (AS/SAS) is one of the most common heart defects occurring in boxers. Stenosis is narrowing
of the aorta, right below the aortic valve, which forces the heart to work harder to supply blood. Reduced blood flow can
result in fainting and even sudden death. The disease is inherited but its mode of transmission is not known at this time.
Diagnosis must be made by a veterinary cardiologist. Breeding dogs must be properly screened for this disease and affected
dogs must not be bred.
is an electrical conduction disorder which causes the heart to beat erratically some of the time and can result in weakness,
collapse or sudden death. These arrhythmias are difficult to detect with any certainty by listening to the heart with a stethoscope.
Cardiomyopathy is a genetically inheritable condition with devastating results. Because a dog cannot be cleared of cardiomyopathy
by a routine veterinary examination and the disease may not show itself until after a dog reaches breeding age, it is important
that all breeding stock are properly screened for this disease. Boxer cardiomyopathy is a distinct disease from the
dilated cardiomyopathy common in some other breeds. Other names for BCM are Boxer Arrythmic Cardiomyopathy (BAC), Familial
Ventricular Arrhythmia (FVA) and Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).
Hip dysplasia is an inheritable malformation of the
hip joint leading to osteoarthritis. The hip joint is a ball and socket joint, where the top of the thigh bone fits into
a socket in the pelvis. The bones are held in place by ligaments. Hip dysplasia occurs when the socket is poorly formed or
the ligaments are loose, enabling the ball of the femur to subluxate – to slide part way out of its socket. Over time
this causes degeneration of the joint (osteoarthritis) and the dog suffers pain and becomes weak and lame in the hind end.
Hip dysplasia is a progressive disease, meaning that it becomes worse with time. Hip dysplasia has polygenic inheritance,
meaning it is caused by the inheritance of multiple genes. It is not yet known how many, or which genes are involved. Factors
that can make the disease worse include excess weight, excess or prolonged exercise before maturity, a fast growth rate, and
high-calorie or supplemented diets.
Hypothyroidism describes an inactive thyroid gland which can
be responsible for such conditions as epilepsy, alopecia or hair loss, obesity, lethargy, hyperpigmentation, pyoderma and
other skin conditions. While not considered life threatening, the quality of life for a dog suffering from hypothyroidism
is much reduced.
Corneal dystrophy is 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.
Demodectic mange: The
demodex mite lives on the skin of all dogs, and is passed to puppies by their dam. In healthy dogs, this mite causes no problems.
However, demodectic mange can occur when a dog has a weakened or compromised immune system. The American Academy of Veterinary
Dermatology passed a resolution in 1983 suggesting that all dogs that develop generalised demodex should be neutered or spayed
as there is a genetic link to the development of generalised demodectic mange. Demodectic mange can occur in localised
form, which is characterised by a few spots that do not itch. These patchs usually appear on head, neck and fore limbs. Ninety
percent of those puppies that develop localised demodex will heal on their own. Ten percent of those puppies will go on to
have generalised demodex.
Cancer: Boxers are particularly prone to the development of mast cell tumours,
lymphoma and brain tumours. White boxers, and coloured boxers with white markings should be protected from the sun as they
are liable to develop skin cancer if allowed to burn.
Bloat or Gastric
dilatation-volvulus (GDV) is a very serious condition that occurs when the stomach becomes distended with air, and then twists
on itself while dilated. This interferes with the blood supply digestive organs, blocks the passage of food, thus leading
to worse bloat. The distended stomach impedes the normal return of blood to the heart, causing a decrease in blood pressure
and drastically reduced cardiac output. Blood/oxygen-deprived tissues start to die, releasing toxins into the blood stream
which among other adverse effects, cause serious disturbances in heart rhythms (cardiac arrhythmias). Dogs affected by bloat
can die in hours. Dogs most susceptible to bloat are the large, deep-chested breeds, in whom the stomach appears to
be more mobile within the abdomen. Risk factors are: hereditary predisposition, over-eating (large meals), rapid eating, raised
feeders, pre-moistening of dry food preserved with citric acid, feeding dry food with a fat in the top four ingredients. The
risk of bloat increases with age. Feeding a food with a rendered meat ingredient, inclusive of bone, in the first four ingredients
decreases the risk of bloat.
Purdue veterinary research team, who conducted a research study in 2000 into the risk factors associated with bloat concluded
these are the things you can do to help prevent bloat:
a.. The strongest recommendation to prevent GVD (bloat) should
be to not breed a dog that has a first degree relative that has had bloat. This places a special responsibility on an owner
to inform the breeder should their dog bloat.
b.. Do not raise the feeding dish.
c.. SLOW the dog's speed of eating.
Allergies: Boxers are rather prone to allergies, which can be environmental or food related. These
often translate into itchy, scaly and sometimes infected skin. Boxers do not tend to do well on foods that have a high grain
content, particularly those including corn, wheat or beet pulp.
Deafness: About 20%
of white boxers are deaf, due to their lack of pigmentation and suppression of blood supply to the cochlea (inner ear). White
boxers should not be bred since the genes responsible for deafness in whites are inheritable. Breeding dogs that carry the
extreme white spotting gene (white boxers have two copies of this gene) will cause pigment dilution in all offspring and increase
the incidence of deafness throughout the breed.
Genetic Testing Available
Holter Monitor: A 24-hour EKG (electrocardiogram)
that tests for the presence of PVCs (Premature Ventricular Contractions). This test screens for Boxer Arrythmic Cardiomyopathy,
and should be repeated yearly. There is, at this time, no set number of PVCs that would be considered "affected" with BAC.
A zero or low number of PVCs does not mean that the dog is free of BAC, it only means that the dog was not exhibiting PVCs
during that 24-hour period. However, consistent zero/low readings on yearly Holtering would indicate a higher possibility
that the dog is not affected with BAC.
Doppler Echocardiogram: An ultrasound of the heart that detects
abnormal flow velocities and allows for the diagnosis and quantification of the severity of Aortic Stenosis. A clear Doppler
after the dog is 24 months of age is considered conclusive (the dog does not have AS). Some studies show that Aortic Stenosis
is a polygentic (cause by several genes) disease, so two clear parents can produce affected offspring.
Cardiac Auscultation: A stethoscopic
examination of the heart that detects murmurs that may be indicative of AS. According to the UK Breed Council Control Scheme,
a dog that is found to have no murmur or a Grade 1 murmur upon auscultation after 12 months of age is considered normal and
acceptable for breeding.
OFA Heart: The OFA will certify dogs as "normal" if they are found, upon ausculatation after 12 months
of age, to be without a cardiac murmur, or with an innocent heart murmur that is found to be otherwise normal by virtue of
an echocardiographic examination which includes Doppler studies. Screening can be done by a general practice veterinarian,
a specialist, or a cardiologist. Submission of results is voluntary. OFA Heart testing may detect Aortic Stenosis, although
mild cases may go unnoticed if auscultation is performed by a general practice vet. It will not detect Boxer Arrythimic Cardiomyopathy.
OFA has developed a database registry for Holter Monitor results for the Boxer breed. Submission of results is voluntary and
they are confidential.
**All heart testing should be performed by a board-certified veterinary cardiologist.**
Hips (Orthopedic Foundation for Animals Inc): An X-ray of the pelvic joint to screen for hip dysplasia. Ratings of
"Excellent," "Good," or "Fair" are considered to be free of HD. One view is taken and submission of results is voluntary.
The X-rays must be taken after the dog is 24 months of age. There are several other factors that influence the expression
of HD, including diet and environment, and two clear parents can produce dysplastic puppies.
(University of Pennsylvania Hip Improvemnt Prgrm) An X-ray of the pelvic joint to screen for hip dysplasia. Laxity of the
hips is evaluated and compared to the breed average (the Boxer breed average is .48 laxity). Three views are taken and
submission of results is mandatory. PennHip X-rays can be taken as early as 16 weeks, although most feel a definitive rating
should wait until the dog is older.
Thyroid: A blood test to detect autoimmune thyroiditis. Annual
testing through 4 years of age is recommended, after that, testing every other year should suffice. A negative at any one
time will not guarantee that the dog will not develop thyroiditis. Most vets do not perform a full thyroid panel - as a result,
there are only six laboratories that are approved for OFA thyroid certification: the veterinary laboraties at Michigan State
University, Cornell University, University of Guelph, University of Minnesota, University of California - Davis, and Texas
CERF (Canine Eye Registration Foundation) testing screens for heritable eye diseases such as PRA (Progessive Retinal Atrophy). Results are
kept in a centralized, national registry. Testing must be performed by a member of the American College of Veterinary Ophthalmologists.
Submission of results is mandatory but confidential. CERF screening is repeated yearly.