Inherited Diseases in Popular Dog Breeds: What the Research Says and How to Screen

Key takeaways

• Some health problems run in breeds because of inherited traits or body shape. Knowing your breed’s risks lets you plan screening and spot early signs, but a breed risk is not a certainty for any single dog.
• Health testing helps you choose a puppy, but only if you know what the results mean. A “CHIC number” shows that testing was done, not that the results were good ¹⁰.
• Five conditions come up most often in popular breeds: hip dysplasia, brachycephalic airway syndrome, intervertebral disc disease, degenerative myelopathy and dilated cardiomyopathy. Each has a different mix of genetics, body shape and environment.
• Several of these conditions have DNA tests, but a clear result does not always mean a dog is safe. Some tests are specific to certain breeds or cover only some of the genes involved ⁸.
• Weight, exercise and early veterinary checks reduce the impact of many of these conditions, even in dogs who carry the risk.

How breed-linked disease works

Dogs have been bred for looks and jobs for hundreds of years. Breeding closely related dogs, or selecting for a body shape, can also concentrate genetic variants that raise disease risk. This is why certain breeds are known for particular problems, and why the same condition can be common in one breed and rare in another.

It helps to separate a few ideas:

• Inherited (genetic) disease: caused by gene variants passed from parents to puppies. Some are simple, with one gene and a clear test. Many are complex, involving several genes plus environment.
• Breed predisposition: a breed is over-represented in a condition, but not every dog gets it.
• Conformation-related disease: caused by body shape, such as a very short skull. The shape itself is inherited, and so is the risk.
• Environment still matters: weight, exercise, injury and age change whether a gene variant turns into disease.

The practical consequence is that no breed is free of health problems, and no health test can guarantee a perfect dog. What you can do is choose breeds and breeders thoughtfully, ask for testing results, and keep your dog fit and well checked.

How to read health testing

When you buy a purebred puppy, you may hear about “health clearances” and a “CHIC number”. The Canine Health Information Center (CHIC) is a database run by the Orthopedic Foundation for Animals (OFA) with the AKC Canine Health Foundation. Each breed’s national club decides which tests are required for that breed ¹⁰.

What a CHIC number means. It shows a dog has completed the tests that are required for its breed, and that the owner agreed to publish the results. It does not say the results were normal; a number is issued whether results are normal or abnormal ¹⁰. So the number is a starting point. Ask to see the actual results.

What to look for.

• Which tests apply to your breed, and whether both parents have been tested. The OFA lists the conditions recommended for each breed ¹¹.
• The actual results, with registry or certificate references you can check, not just a breeder’s word.
• Whether the test was done at the right age. Some conditions can only be assessed once a dog is mature.
• Whether the breeder is honest about what testing cannot tell them. Good breeders talk openly about problems in their lines.

Types of tests. Health tests fall into three groups, and each answers a different question:

1. Physical screening such as X-rays for hips and elbows, eye exams or heart exams, which show what a dog is like now.
2. DNA tests, which look for specific gene variants and can be done on a puppy or an adult.
3. Ongoing monitoring, such as repeated heart screening, for conditions that develop later in life.

Hip dysplasia

What it is. Hip dysplasia is a developmental condition in which the hip joint does not fit together properly. Over time, the poor fit leads to wear and osteoarthritis, pain and stiffness. It affects many breeds, and large dogs often show it most.

What the research says. The most detailed data come from the Orthopedic Foundation for Animals registry. A study of OFA records in the United States and Canada examined breed, sex, season of birth and other factors across a very large number of dogs, and found large differences between breeds ¹. The study also notes that registry data come from dogs whose owners chose to submit X-rays, so they may not represent all dogs of a breed ¹.

Hip dysplasia is influenced by both genes and environment. Genetics sets the risk, while growth rate, body weight and exercise as a puppy can influence how severe it becomes. Breeding from dogs with good hips improves the odds, but it is not a guarantee.

How it is screened.

• OFA evaluation. X-rays are submitted to OFA and read by board-certified radiologists. A formal OFA certificate requires the dog to be at least 24 months old.
• PennHIP. A different method, which measures looseness of the joint (the “distraction index”). It can be done as early as 16 weeks of age.

What owners can do. Keep puppies lean, because extra weight puts extra stress on developing joints. Avoid forcing repetitive, high-impact exercise in young, fast-growing large-breed puppies, and talk to your vet about safe activity. If your dog is already affected, treatment options range from weight management, physical therapy and pain control to surgery in some cases.

Signs to watch for. Reluctance to jump or climb stairs, “bunny hopping” when running, stiffness after rest, a swaying walk, or less interest in play. Mention any of these to your vet.

Brachycephalic obstructive airway syndrome (BOAS)

What it is. Brachycephalic (“short-headed”) dogs, including bulldogs, pugs and French bulldogs, have shortened skulls. The soft tissue inside the nose and throat does not shorten to match, so airways can be narrow and obstructed. This is called brachycephalic obstructive airway syndrome, or BOAS.

What the research says. A study from the Royal Veterinary College found that the risk of BOAS increases as the face becomes shorter and more exaggerated, and that a thicker neck and obesity also increased risk ². A later study of pugs, French bulldogs and bulldogs identified narrow nostrils and other conformational features as risk factors, and suggested body condition may play a part ³.

An important finding concerns owners. A Royal Veterinary College survey reported that most owners of affected dogs do not recognize the problem, and often see noisy breathing as normal for the breed ⁴. Snoring and snorting are common in these dogs, but they are not harmless.

Signs to watch for. Noisy breathing at rest or on exertion, snoring while awake, gagging or retching, tiring quickly on walks, and sleeping with the chin propped up to breathe. Collapse in warm weather or after exercise is an emergency.

What owners can do.

• Keep your dog lean, because extra weight worsens breathing problems ².
• Avoid heat, humidity and strenuous exercise, and never leave a flat-faced dog in a car.
• Use a harness, not a collar, so nothing presses on the neck.
• Ask your vet to assess your dog’s airway, especially before any anesthetic. Some dogs benefit from surgery that widens the nostrils or shortens an overlong soft palate, and the decision belongs with your vet.

Choosing a dog. If you are drawn to a flat-faced breed, look for a breeder who selects for a longer muzzle, open nostrils and a slimmer neck, and ask whether the parents have had an airway assessment. The research suggests a less extreme face carries lower risk ².

Intervertebral disc disease (IVDD)

What it is. The spine is cushioned by discs between the bones. In IVDD, a disc degenerates, bulges or ruptures and presses on the spinal cord. Signs range from back pain to wobbliness to sudden paralysis.

Who is affected. IVDD is especially common in “chondrodystrophic” breeds, which have short legs and long backs, and dachshunds are the best-known example. A large genetic study identified a DNA insertion on chromosome 12, called an FGF4 retrogene, as strongly associated with IVDD in these breeds ⁵. Estimates of how many dachshunds are affected vary widely between studies, from about one in five to well over half depending on how the population was studied ⁵.

A genetic test, but with limits. A DNA test for this variant exists, but it does not settle the question for every dog or breed. A study of wire-haired, long-haired and smooth-haired dachshunds found that this variant on its own was not a reliable predictor of disc disease, and suggested X-ray scoring of disc calcification as an additional tool for breeding decisions ⁶. Disc disease is also influenced by age, weight and injury, not only genes.

Signs to watch for. Crying out, reluctance to move or jump, a hunched back, shaking, knuckling of the paws, wobbliness in the back legs, or sudden inability to walk. Sudden weakness or paralysis is an emergency. Early treatment gives the best chance.

What owners can do. Keep your dog at a healthy weight, use ramps instead of letting small dogs jump from furniture, support the back when carrying, and use a harness. If your dog shows pain, rest it and call your vet the same day.

Degenerative myelopathy (DM)

What it is. Degenerative myelopathy is a slowly progressive disease of the spinal cord that causes weakness and loss of coordination in the back legs, usually in older dogs. It is generally progressive and there is no cure ⁷.

The DNA test. A mutation in a gene called SOD1 is linked to DM, and a DNA test can sort dogs into three groups: two normal copies (clear), one copy (carrier) and two copies (at much higher risk) ⁷. The UC Davis Veterinary Genetics Laboratory lists many breeds in which affected dogs have been found, including Boxers, Bernese Mountain Dogs, Cardigan Welsh Corgis and Australian Shepherds ⁷.

Interpreting a result. Two copies do not guarantee disease: not every dog with two copies develops it ⁷. Equally, a dog with weak back legs may have a more common and treatable problem, such as arthritis or disc disease, so a test result must be read alongside a veterinary exam. A definite diagnosis of DM requires examination of the spinal cord after death ⁷.

What it means for breeding and buying. The test is most useful for breeders, who can avoid pairing two dogs in a way that produces at-risk puppies without having to remove good dogs from a breeding program. For a puppy buyer, a “clear” result for DM is reassuring but is only one piece of the picture.

What owners can do. There is no cure, but physiotherapy, safe exercise, mobility aids and good nursing care can help dogs stay comfortable. Talk to your vet if you notice your dog’s back feet scuffing, knuckling or crossing.

Dilated cardiomyopathy (DCM)

What it is. In dilated cardiomyopathy, the heart muscle weakens and the heart chambers enlarge, so the heart pumps less well. It can cause heart rhythm problems, fainting, heart failure or sudden death. It is the most common heart disease in large-breed dogs ⁹.

Breeds and genetics. Cornell’s Riney Canine Health Center lists Dobermans, Boxers, Great Danes, Irish Wolfhounds, Newfoundlands and several other breeds as predisposed ⁸. In Dobermans, two gene variants, called PDK4 and TTN, are the best known; the highest genetic risk is seen when both are present ⁸. Genetic tests exist only for some breeds, mainly Boxers and Dobermans, and a negative result does not rule out disease, because not every genetic cause has been found ⁸.

Why screening matters. DCM often has a long “silent” stage in which a dog looks completely well but already has abnormal heart rhythms or early changes on a heart scan. A review of DCM screening recommends that screening for hidden (occult) disease in Boxers and Dobermans start around three years of age, using 24-hour heart rhythm monitoring (Holter) and heart ultrasound (echocardiography) ⁹. It also stresses that screening should be repeated, usually yearly, because a single normal result does not rule out DCM developing later ⁹.

Signs to watch for. Fainting or collapse, tiring easily, coughing, fast or labored breathing, a swollen belly and reduced appetite. Any of these deserves prompt veterinary attention, and fainting or labored breathing is an emergency.

What owners can do. If you have a predisposed breed, ask your vet about a cardiology screening plan, even if your dog seems perfectly healthy. Ask your breeder whether the parents and relatives have been screened, and whether any heart disease or sudden deaths have occurred in the line.

Choosing a puppy: questions to ask a breeder

1. Which health tests does my breed’s national club recommend, and have both parents had them?
2. Can I see the actual results (not only a CHIC number), with certificate or registry numbers?
3. Which conditions have appeared in the line, including in relatives, and how did you respond?
4. For flat-faced breeds: do the parents have open nostrils and a longer muzzle, and have they had an airway assessment?
5. For long-backed breeds: what do you do to reduce the risk of disc disease?
6. For breeds prone to heart disease: are the parents and close relatives screened by a cardiologist, and how often?
7. What health guarantee do you offer, and what happens if a serious inherited problem appears?
8. Will you take the dog back if I can no longer keep it?

Be cautious of anyone who is vague about testing, dismisses a breed’s known problems, always has puppies available, or sells puppies without letting you meet the mother.

If you already have a dog

Learning about your breed’s risks is not a reason for worry, but it is a reason for a plan:

• Tell your vet your dog’s breed and ask which conditions to watch for.
• Keep your dog lean, since weight worsens most of the conditions in this guide.
• Learn the early signs for your breed and act on them quickly.
• For mixed-breed dogs, consider asking your vet about a DNA test. These tests vary in quality and in what they cover, so treat results as one input and discuss them with your vet, not as a diagnosis.
• Keep records of any health tests, scans and symptoms, and share them with your vet.

Questions to ask your vet

1. Which inherited conditions are most relevant to my dog’s breed or mix?
2. Which screening tests are worth doing, and at what age?
3. What early signs should I watch for, and when is it urgent?
4. Could my dog’s weight, exercise or equipment be adjusted to lower risk?
5. If a DNA test shows a variant, what does that mean for my dog in practice?

FAQ

Are mixed-breed dogs healthier than purebreds? Not automatically. Mixed breeds can inherit the same problems as their parent breeds, and some can inherit from more than one. Health depends on the specific dogs involved.

Does a clear DNA test mean my dog will never get the disease? Not always. Some tests cover only some of the genetic causes, and environment also plays a part ⁸.

Is snoring normal in flat-faced breeds? It is common, but it can be a sign of obstructed airways. Research suggests many owners assume breathing noise is normal for the breed ⁴. Ask your vet to assess your dog.

Can I prevent these diseases? You often cannot prevent the underlying genetics, but good choices when selecting a puppy, a healthy weight, safe exercise and early screening reduce how much they affect a dog’s life.

How can I tell a responsible breeder? They test their breeding dogs for the conditions relevant to the breed, show you the results, discuss problems in their lines openly, and take responsibility for the puppies they produce.