Great Danes are by far a very healthy, hearty, tough breed. Some portrait them as sickly couch potatoes that cannot handle exercise, cold, heat or the element, are always sick and require constant human and Veterinary care. This is as far from the truth as can be. Great Danes do have potential for over 68 known diseases. Some are devastating, others are mild. I will list the known diseases by body system and the tentative mode of inheritance. No DNA tests have yet been developed to detect diseases in Great Danes. The most important step in eradicating diseases from any breed begins with the breeders. They MUST know the background on their dogs/line. Many breeders are afraid to state they have, or carry any diseases. The thought is that no one will want to buy their offspring or breed to their animals. Any breeder with knowledge of genetics knows this to be false as all dogs carry 3 or more detrimental genes. Too many breeder only breed for what they can see (conformation) whereas conformation should be third on the list of importance. First and foremost should be health, then temperament, then conformation. You can have a gorgeous Dane that bites, develops elbow dysphasia and drops dead at 3 from Aortic Stenosis…. Then what have you really got? To top it off, this dog may have been bred to numerous bitches who have now passed many of these traits on to their offspring (if they were also carriers or affected.) Breeders should be able to map a “genetic pedigree” on all their dogs, siblings and their ancestors, marking dogs that were/ are affected with a disease, or is/are carriers. The only way to accomplish this is to follow the lifetime health of all breeding stock AND their generational offspring.
CARDIOVASCULAR SYSTEM DISORDERS
AORTIC STENOSIS: SAS is a congenital heart disease involving a narrowing or stricture just below the aortic valve. The ventricle responsible for pumping blood through the stenotic valve frequently enlarge to a degree proportional with the tightness of the stenosis. The pattern of transmission is most compatible with an autosomal dominant/polygenic trait with variable expressivities. Affected animals and those with a family history of SAS should not be used in breeding program.
DILATED CARDIOMYOPATHY: DCM occurs when the heart chambers enlarge and the walls of the ventricles become thin. This causes the heart muscles to weaken and eventually fail . A nutritional mechanism, autoimmunity, defect in L-Carnitine and taurine or virus have been implicated in the development of DCM. Although a genetic tendency is suspected, long term studies are not yet available. Affected animals should not be used in a breeding program.
MITRAL VALVUE DISEASE: A chronic valvular disease that typically involves the atrium ventricular valves and results in mitral regurgitation, rupture of the chordae tendons and potential left sided heart failure. There is thought to be a genetic tendency to experience degeneration of the collagen in the heart valves. Affected animals should not be used in a breeding program. Only breed those with no family history of chronic valvular disease.
PATENT DUCTUS ARTERIOSIS: PDA occurs when normal fetal communication between the nonfunctional lungs and the aorta fails to close after birth. Surgery before 5 months of age has a success rate of 90%, uncorrected, 50% die within the first year. It is inherited as a polygenetic trait. Affected animals and those with a prominent family history of PDA should not be used in a breeding program.
TRICUSPID VALVE DYSPLAISA: A congenital malformation of the triuspid valve complex resulting in insufficiency and regurgitation of blood into the right atrium. Affected animals should not be used in a breeding program.
PERSISTANT RIGHT AORTI ARCH: A developmental anomaly in which the aorta is formed by the right 4th aortic arch instead of the left 4th arch. The esophagus and trachea are encircled by a vascular ring resulting in aspiration pneumonia and regurgitation. Affected dogs should not be used in a breeding program.
DENTAL DISORDERS
BRACHYGNATHISM: Also known as an overshot jaw, is a condition in which the mandible is significantly shorter than the maxillae. Mode of inheritance is an inherited defect, and individuals affected should not be used in a breeding program.
MALOCCLUSION: Denotes any abnormality in how the upper and lower teeth meet. Level bite is a malocclusive disorder in which the front teeth meets end to end. Reverse scissors bite occurs when the upper incisors fall just behind the lower incisors. Open bite occurs when a gap of at least 5mm is present between the top and bottom incisors when the mouth is closed. Wry mouth is a version of either brachygnathia or pragmatic affects only one side of the head. Animals requiring orthodontic procedures should not be used in a breeding program.
MISSING TEETH: Anodontia is the complete absence of teeth, and oligodontia refers to several missing teeth. Mode of inheritance is thought to be a autonomic recessive trait. Affected animals should only be bred to non carriers/non affected dogs.
PROGNATHISM: Known as undershot jaw, occurs when the mandible is significantly longer than the maxilla. Mode of inheritance is thought to be an inherited defect. Affected animals should only be bred to non carriers/non affected dogs.
Dermatological Conditions
ACNE: Muzzle folliculitis and furunculous; follicular papules of various sizes, which are generally hairless. May ulcerate and produce purulent exudates. Mode of inheritance is not known. Affected animals may be bred to non affected animals.
ACRUL PRURITIC DERMATITIS: AKA Lick Granulomas, is a disorder in which the dog continues to lick at the limbs, abrading the skin and creating ulcers and raw, weeping areas. No direct mode of inheritance has been established. Affected animals may be bred to unaffected animals.
ANASARCA: Refers to a generalized edematous condition seen in newborn puppies. This trait can be lethal, other cases may be mildly affected. Mode of inheritance is considered to be recessive. Affected dogs should not be used in a breeding program and the parents should be considered carriers.
CALCINOSIS CIRCUMSCRIPTA: A condition characterized by dystrophic mineralization of tissue, and abnormal deposits of calcium in the skin and subcutaneous tissue. Presents as well circumscribed, non painful subcutaneous swelling with occasional ulceration and fistulation. Mode of inheritance has not been determined. Affected animals should not be used in a breeding program.
COLOR DILUTION ALOPECIA: A condition that describes the patchy, poor haircoat that can develop in animals bred for unusual hair color. Mode of inheritance is thought to be a double recessive trait. Affected animals should not be used in a breeding program. Parents and offspring must be considered carriers.
DEMODECTIC MANGE: An inflammatory disease of the hair follicles that is part from the presence of Demodex mites and part inherited or acquired immune defect. The mode of inheritance has not been determined. Affected animals should not be used in a breeding program.
EPIDERMOLYSIS BULLOSA: EB refers to a group of diseases that causes blistering and structural defects at various levels of the basement membranes. Affected animals should not be used in a breeding program. Parents and offspring may be considered carriers.
FOLLICULAR DYSPLASIA: Abnormal hair loss or defective follicle formation of the hair shaft. Findings are hair loss, changes in coat quality and hyper pigmentation of the skin in affected areas. Mode of inheritance is thought to be a recessive trait. Affected animals should not be used in a breeding program.
ZINC RESPONSIVE DERMATOSIS: A scaling and crusting disorder that does not result from a dietary deficiency of zinc. Affected dogs have crusting on the nose, eye areas, footpads, elbows, and hocks. ½ develop itching. Some ingredients in dog foods can interfere with the zinc absorption; these include calcium, fiber, iron, tin, and copper. Mode of inheritance is not known. Affected animals should not be used in a breeding program.
ENDOCRINE DISORDERS
HYPOADRENOCORTICISM (ADDISON’S DISEASE): Addison’s disease causes primary atrophy of the adrenal cortex or secondary pituitary insufficiency. Signs include weakness, depression, vomiting, diarrhea, and abnormal cardiac function. Mode of inheritance is believed to be an immune-mediated destruction of the adrenal gland. Affect animals should not be used in a breeding program.
HYPOTHYROIDISM: Results in a progressive deficiency of thyroid hormone. Increased susceptibility to infection and lower energy levels are common, as is alopecia, weight gain, intolerance to cold, reproductive failure, anemia and poor hair regrowth. Mode of inheritance is not known. It is difficult to justify breeding affected dogs.
GASTROINTESTINAL DISORDERS
ESOPHAGEAL HYPOMOBILITY: Regurgitation, weight loss, recurrent respiratory infections, and retarded growth rate due to the esophagus failing to push food into the stomach. Mode of inheritance is not known. Affected animals should not be used in a breeding program.
ESOPHAGEAL ACHALASIA: Congenital mega esophagus presents as regurgitation in puppies, failure to thrive, excessive saliva, and respiratory distress second to aspiration pneumonia. Mode of inheritance in not known. Affected animals should not be used in breeding programs.
EXOCRINE PANCREATIC INSUFFICIENCY: Usually results from pancreatic atrophy. The condition is progressive and results in weight loss and semi-formed stools in the face of a ravenous appetite. Mode of inheritance in not known. Affected animals should not be used in breeding programs.
GASTRIC DILATATION VOLVULUS (BLOAT): Bloat occurs when the stomach becomes distended with air. The air gets swallowed into the stomach when susceptible dogs exercise, gulp their food/water or are stressed. Mode of inheritance in not known. Affected animals should not be used in breeding programs.
PTYALISM: A hyper secretion of saliva characterized by profuse drooling. It occurs when there is a normal quantity of saliva but an increase in drooling secondary to conformational abnormalities or swallowing disorders. Mode of inheritance in not known. Affected animals may be bred to unaffected dogs.
HEMOLYMPHATIC DISORDERS
LYMPHEDEMA: Caused by developmental defects in the lymphatic and lymph nodes. Characterized by pitting edema, typically in the limbs and abdomen or pleural cavities. Mode of inheritance is a dominant trait. Affected animals should not be used in a breeding program.
VON WILLEBRAND DISEASE: VWD is the most common bleeding disorder found in dogs. Mode of inheritances recessive. Breeding animals with Von Willebrand trait but no evidence of bleeding disorders are not straightforward. It is not recommended to breed animals with VWD. These dogs should not be a part of any breeding program.
IMMUNOLOGIC DISORDERS
PEMPHIGUS: Pemphigus Vulgaris is characterized by bullous lesions along the mucous membranes of the mouth, anus, prepuce, vulva and oral cavity. Bacterial infections often complicate lesions. Mode of inheritance is not determined. Affected animals should not be used in breeding programs.
BULLOUS PEMPHIGOID: A complex of blistering conditions characterized by auto antibody deposition at the junction between the epidermis and dermis, with blister formation immediately deep into the dermis. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
MUSCULOSKELETAL DISORDERS
ABDOMINAL HERNIAS: Refer to defects in the wall of the abdomen that may allow the protrusion of abdominal contents. Most umbilical hernias only trap fat in the umbilical ring and are of little clinical significance. Inguinal hernias result from a congenital inguinal ring anomaly. Mode of inheritance is recessive/undetermined. Affected animals should be bred to non affected dogs.
CORE MYOPATHY: Affects skeletal muscles fibers and causes muscle atrophy. Mode of inheritance is not known. Affected animals should not be used n a breeding program.
CRANIOMANDIBULAR OSTEOATHY: Proliferation of bone that typically affects the lower jawbone and occasionally other bones of the head. Mode of inheritance is recessive. Affected animals should not be used in a breeding program even if they recover fully. Parents should be considered carriers and the offspring as possible carriers.
ELBOW DYSPLASIA-FRAGMENTED CORONOID PROCESS: Most common form of elbow dysphasia in which part of the elbow joint breaks away from the bony anchor. Characterized by stiffness, stilted gait or lameness. Mode of inheritance is Polygenetic. Affected animals should not be used in a breeding program, nor should dogs that produce a litter evidencing elbow dysphasia.
ELBOW DYSPLASIA-OSTEOCHONDROSIS of the MEDIAL CONDYLE: OCD of the medial humeral condyle is similar to the disorder seen in the shoulder. It involves the lower end of the humerus rather than the upper part. Mode of inheritance is not determined. Affected dogs should not be in the breeding program.
ELBOW DYSPLASIA-UNUNITED ANCONEAL PROCESS: UAP occurs when the bone growth center in the Anconeal Process of the elbow fails to unite with the ulna of the foreleg. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
HIP DYSPLASIA: An abnormal development of the hip joint. It is actually a genetically transmitted tendency for the hips to develop laxity of the joints. Several factors combine to determine if a predisposed animal will develop hip dysphasia. These include body size, conformation, growth patterns, pelvic muscle mass, caloric load, and electrolyte balance in dog foods. All supplements should be avoided, especially calcium, phosphorus, and vitamin D. Mode of inheritance is polygenetic. Affected dogs should not be used in a breeding program.
HYPERTROPHIC OSTEODYSTROPHY: A developmental condition that affects young rapidly growing large/giant breed dogs. Variable lameness and pain on palpation, fever, anorexia, and depression, affects the distal radius, ulna, and tiba. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
MYTONIA: Disorder of the skeletal muscles, characterized by delayed relaxation of the muscle fibers causing the muscles to continue to contract after voluntary movement ceases. Mode of inheritance in recessive. Affected animals should not be used in a breeding program.
OSTEOCHONDROSIS (OCD): OCD causes flaps of cartilage to be exposed in the joints with inflammation resulting. It is most common in the shoulders, elbows, and hind legs of Great Danes. Factors that cause OCD are many, trauma, poor nutrition, and hereditary have all been explored. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
PANOSTEITIS (PANO): Pano refers to an inflammatory condition that affects the leg bones, characterized by excessive bone remodeling, and lameness that appears to migrate between legs. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
PATELLAR LUXATION: Condition in which the kneecap slips out of their usual resting places and lodge on the medial aspects or lateral aspects of the knee. Mode of inheritance is polygenetic. Affected animals should not be used in a breeding program.
CROOKED TAIL: An abnormal bend or kink in the tail. Mode of inheritance is not determined. Affected animals should only be bred to non affected/non carriers.
LATERAL TORSION OF THE HIND FEET: The anterior surface if the foot is directed to the side to varying degrees. Mode of inheritance is not determined. Affected animals should only be bred to non affect/non carrier dogs.
MULTIPLE CARTILAGINOUS EXOSTOSES: A silent disease that may produce pain on occasion, if pressure is put on the protuberances. There may be lameness intermittently. Bony nodules can be felt on the ends of the long bones or ribs, but may be found anywhere on the body. Mode of inheritance is not determined. Affected animals should only be bred to non affect/non carriers.
PREMATURE CLOSURE OF THE ULNA: The ulna stops growing sooner than the radius causing the wrists to turn in and the front feet to turn out. Mode of inheritance is recessive. Affected animals should only be bred to non affected/non carriers. Parents should be considered carriers.
NERVOUS SYSTEM DISORDERS
AGGRESSION: Extremely assertive or forceful with other dogs and/or people. May attack or bite without reasonable provocation. Aggression cannot entirely be controlled through genetics, but it is recommended that no dog that demonstrates unprovoked aggression towards people ever be bred.
CEREBELLAR DEGENERATION: Diseases of the cerebellum that tend to be breed specific, resulting in progressive neurological signs including in-coordination, ataxia, paralysis and generally death. Mode of inheritance though to be recessive. Affected animals should not be used in a breeding program. Parents should be considered carriers.
CERVICAL SPONDYLOPATHY (WOBBLER’S SYNDROME): Condition that appears to be a failure of proper support around the vertebrae. Preliminary research suggests that excess dietary calcium, protein, phosphorus, genetic factors, injury and overfeeding may all be involved. Mode of inheritance is recessive. Affected animals should not be used in a breeding program. Parents and offspring should be considered carriers. Owners of related dogs should be notified of the condition.
DEAFNESS: A loss of hearing that may be partial or complete, resulting from degeneration of the inner ear structures and neurons of the spiral ganglion. Deaf dogs are not born this way, they lose hearing between 3-4 weeks after birth. Mode of inheritance is thought to be dominant. Studies have shown that deafness is strongly associated with parental hearing status, breed only animals from families in which deafness is not a problem.
SEIZURE DISORDERS: Partial seizures are a manifestation of a focal epileptogenic event in the cerebral cortex. Generalized seizures can be subdivided into convulsive (grand-mal) and non-convulsive
(petitmal). Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
OPHTHALMOLOGICAL DISORDERS
CATARACTS: An opacity of the lens of the eye. Cataracts can be divided by stages; incipient, immature, mature, hyper mature. By location; anterior or posterior capsule or cortex, equator or nucleus. Mode of inheritance and age of onset; congenital, prenatal, juvenile, adult onset, or senile. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
DISTICHIASIS: Eyelashes that may project towards the surface of the eye from abnormal locations. May not be problematic if the hairs are soft and fine. Mode of inheritance is not determined. Affected animals may only be bred to non-affected/non-carriers.
ECTROPION: Eyelids are turned out and often have the appearance of drooping. Animals may be prone to conjunctivitis. Mode of inheritance is not determined. Affected animals may be bred to non-affected/non-carriers.
ENTROPION: Eyelids are turned in, often resulting in abrasive damage to the cornea. Mode of inheritance is not determined. Affected animals should only be bred to non-affected/non-carriers.
ENOPHTHALMOS: Eyeball is recessed into the eye socket. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
EVERSION OF THE NICTITATING MEMBRANE: Cartilage in the third eyelid is abnormal, causing the third eyelid to roll away from or towards the globe. Mode of inheritance is not determined. Affected animals should only be bred to non-affected/non-carriers.
GLAUCOMA: Caused by an increase in fluid pressure within the eye leading to blindness. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
HEMERALOPIA: Day blindness due to progressive degeneration of the cone photo receptors. Sight returns when the dog is returned to dim lighting. Mode of inheritance is recessive. Affected animals should only be bred to non-affected/non-carriers. Parents should be considered carriers.
MICROPHTHALMIA: The condition of a congenitally small eyeball. Usually associated with partial albinism, and deafness. Mode of inheritance is not determined.
Affected animals should not be used in a breeding program.
PERSISTENT PUPILLARY MEMBRANES: Strands of fetal eye tissue appear visually within the eye, typically spanning the pupil. Usually does not cause a vision problem. Mode of inheritance is not determined. Affected animals should only be bred to non-affected/non-carriers.
PROGRESSIVE RETINAL ATROPHY: Visual impairment occurs slowly but progressively with atrophy and degeneration of the retinal tissue. Mode of inheritance is not determined. Affected animals should not be used in a breeding program.
PROLAPSED GLAND OF THE NICTITANS (CHERRY EYE): Refers to an enlarged gland at the base of the nictitating membrane that is displaced from its normal position. Mode of inheritance is not determined. Affected animals should only be bred to non-affected/non-carriers.
PROTRUSION OF THE THIRD EYELID: The third eyelid extends over the globe with no obvious pathology. It may or may not interfere with vision. Mode of inheritance is not determined. Affected animals should only be bred to non-affected/non-carriers.
RETINAL DYSPLASIA: Abnormal development of the retina which can cause visual impairment and blindness. Can be caused by secondary events such as viral infections, certain drugs and intrauterine trauma. Mode of inheritance is not determined. Affected animals should not be used I a breeding program.
REPRODUCTIVE PROBLEMS
CRYPTORCHIDISM: Testicles that have not descended into the scrotum. May be one or both. As a general rule, if the testicles have not descended fully into the scrotum by 4 months of age, they are unlikely to do so. Mode of inheritance is recessive, possibly polygenetic. Affected animals should not be used in a breeding program.
URINARY SYSTEM DISORDERS
RENAL DYSPLASIA: Abnormal differentiation of kidney tissue such as inappropriate or anomalous structures appearing within the renal parenchyma. Mode of inheritance is not known. Families trends have not been reported in association with sporadic cases. Affected animals should not be used in a breeding program.
UROLITHIASIS-CYSTINE: A kidney disorder that allows cystine crystals and stones to form in the urine and potentially to block the urinary tract. Mode of inheritance is recessive/sex-linked. Affected animals should not be used in a breeding program. All offspring will be carriers or affected.
A gene is a unit of hereditary information in cells that is passed down from parents to offspring. It controls the transmission and manifestation of one or more traits. Once in a while, genes mutate, which may give rise to genetic diseases. Genetic diseases can affect all areas of the body.
Scientists are working to understand the underlying causes of hereditary canine diseases, including a determination of the genetic mutations that actually causes the diseases. With this information, scientists can develop diagnostic tests so breeders can reduce or eliminate the incidence of hereditary conditions such as mitral valve disease, hip dysphasia, and epilepsy are kept from producing puppies who will continue to pass on these serious problems.
This work has already brought results, including the discovery of three inherited diseases that affect the retina for which genetic tests have been developed, and some researchers believe that tests for all known canine genetic diseases could be developed within the next 10 years. Eventually, gene therapy for dogs will be used to treat genetic diseases. Currently, genetic testing can help breeders plan breeding that will avoid these canine diseases.