Nobody likes to see their pet suffer, which is why some pet owners spend up to $700 every year on healthcare for their four-legged pals. But sometimes, there’s not much you can do: your beloved pup or kittycat is just genetically predisposed to getting certain illnesses.
In some cases, those conditions are so rare as to be almost unheard of – it’s unlikely you know much about Mucopolysaccharidosis VII, for example – but many others are both common and problematic among our household pets.
So here are some of the most common genetic complaints among cats and dogs – along with how to spot them, and what to do if they turn up.
Dogs: early-onset cataracts
One of the most important inherited disorders in dogs is early-onset cataracts, occurring in up to one in eight of certain breeds. Spaniels are particularly at risk, as are working-type dogs such as Huskies or Great Danes.
“In a healthy eye, light passes through the cornea […] and the lens to reach the back of the eye,” explains a fact file on the condition from the Royal Veterinary College, University of London. “The lens is a transparent disc in normal conditions and is located behind the iris.”
But when an eye becomes affected by cataracts, the lens stops being clear. Instead, it clouds over, stopping light from entering the retina and interfering with the eye’s ability to see.
While cataracts are not life-threatening or painful, they can leave your pup functionally blind if not managed properly. You don’t want to delay it: the only treatment that can restore vision to the eye is surgery, but wait too long and it may not be as effective – or even an option at all.
“Once a cataract reaches maturity, it is more likely to cause increased inflammation within the eye,” explained veterinary nurse Tyler Grogan back in 2020. “This inflammation can prevent a pet from being eligible for vision-restoring surgery by causing secondary issues.”
Moreover, she pointed out, thanks to the condition’s tendency to close off the routes by which fluid would normally escape the eye, cataracts can cause glaucoma. That’s a big problem for getting your pet treated, she explained, since “if a pet has glaucoma, they’re not often a candidate for cataract removal surgery.”
Dogs: hip and elbow dysplasia
Dysplasia (abnormal growth) of the hip and elbow joints is a very common inherited condition for dogs – but they’re especially prevalent in larger breeds like German Shepherds or Saint Bernards. In brief, it’s when the two parts of the joint – the ball and the socket – don’t fit together properly, inevitably leading to a degeneration of the cartilage within the joint, arthritis, and pain for the animal.
“Signs of hip dysplasia include difficulty rising or laying down, difficulty going up and down stairs, inability to jump onto furniture or into a vehicle and reluctance to run or walk,” advised veterinarian Mindy Cohan in 2016. “Depending on the degree of hip dysplasia, medical and sometimes surgical treatments are indicated.”
To a certain extent, this is one of those health issues that we can thank human interference for: “Selective breeding of the disproportionately short legs of breeds such as the Basset Hound and the Dachshund has led to bowed legs and chronic problems with elbow dislocation; the short legs and long back of Dachshunds causes them to suffer more often from ruptured vertebral disks,” explains PBS Nature.
Similarly, “The long neck and large head of breeds such as the Great Dane and the Doberman can cause the compression of the spinal cord in neck vertebrae, leading to wobbling and falling,” while “toy and miniature breeds are more likely to experience patellar luxation, the slipping or dislocation of the kneecaps.”
Despite this, however, hip and elbow dysplasia may just be an unavoidable fact of life for dogs. Certain studies have called into question the idea that interbreeding for pedigree breeds leads to higher incidences of dysplasia, with the authors of one 2015 study covering close to 90,000 dogs concluding that “the physical, quadrupedal structure of a canine may increase the risk of hip dysplasia. For instance, [scholars] report hip dysplasia in a red fox suggesting ancient hip dysplasia liability genes.”
Since hip dysplasia is worse for heavier dogs, one of the most important ways to prevent it is weight management. Once it’s taken hold, though, your pup might need anything from pain meds and physical therapy to full-on surgical hip replacement – so if you want to avoid the more drastic solutions, it’s best to keep an eye on your doggo’s hips and elbow health.
They are perhaps the most striking of all moggies, but white cats with ice-blue eyes pay a price for their beauty. Thanks to an inherited genetic mutation – a dominant gene called “W” – that affects the development of the structures within the ears as well as the cat’s coat and eye color, white, blue-eyed kitties are much more likely than other cats to be deaf.
“If a white cat has 2 blue eyes, it is 3-5 times more likely to be deaf than a cat with 2 non-blue eyes, and a cat with 1 blue eye is about twice as likely to be deaf as a cat with 2 non-blue eyes,” notes charity International Cat Care. “In addition, longhaired white cats are 3 times more likely to be bilaterally deaf.”
Because gene mutations are rarely simple, though, the relationship is not one-to-one – that is, deafness is strongly linked to having a white coat and blue eyes, but not all white cats or white cats with blue eyes are necessarily deaf.
While there’s no treatment for this inherited deafness, affected cats can live long and perfectly happy lives with the condition. Just keep them inside – being deaf, having reduced vision in low-light conditions, and not possessing a human knowledge of traffic laws probably won’t make for a good time for the little guys.
Cats: type II diabetes
We don’t tend to think of type II diabetes as having much of a genetic background – but, in fact, it has a stronger link to family history and lineage than its congenital cousin type I. For further evidence of the role of heredity, look no further than Burmese cats – a breed that is around four times as likely as other cats to develop the condition.
At particular risk are those Burmese cats hailing from Down Under: “Burmese cats in Australia are more at risk of type 2 diabetes than American Burmese cats, or other cat breeds in Australia,” explained Grant Morahan, a professor of immunogenetics from the University of Western Australia’s Centre for Diabetes Research, back in 2020.
“They were bred from only a few founder cats brought here in the 1960s,” he said, “which by chance had more type 2 diabetes susceptibility genes than usual.”
There’s no genetic test for which cats are at risk of developing diabetes – and it should be pointed out that the condition is by no means restricted to Burmese cats only. Much like in humans, though, the symptoms of diabetes in felines include increased thirst and urination, and weight loss despite a normal – or even increased – appetite.
By the same token, prevention follows the same general rules you’ve likely heard from your own human-centered physicians: managing your pet’s weight, encouraging exercise, and administering a specialized diet that’s low in carbs and high in protein. It’s worth keeping a handle on this: should your moggy develop diabetes regardless, you’ll need to give them a daily insulin injection, which likely won’t be fun for anybody (or anykitty) involved.
Cats and dogs: allergies
We know: after blindness, deafness, hip dysplasia, and diabetes, simple allergies don’t sound that worrying. However, they merit a mention purely because they’re just so common – for example, more than one in seven dogs have a skin hypersensitivity issue, with breeds including Dalmatians, Vizslas, and some terriers being especially susceptible.
In fact, our pups’ weakness to things like mites or grass may be more than incidental. “It is thought that dogs are genetically predisposed to become sensitized to allergens in the environment,” notes MSD Veterinary Manual.
“Both male and female dogs can be allergic to materials in the air,” it continues, and while “food allergies are less common than airborne allergies," any breed can develop them.
Similarly, allergies are extremely common in cats too, with certain breeds like Abyssinians, Devon Rexes, and domestic short-haired cats being more prone to developing them.
The bad news? Just like with humans, allergens can be difficult to isolate, and treatment of the condition is a lifelong commitment.
“Controlling symptoms is realistic, curing the disease is not,” advised veterinarian Rebecca Martin. Nevertheless, she continued, “these days, vets have various treatments available for [allergic] dogs” – and cats – “and these should greatly reduce symptoms and increase the quality of life for your companion.”
All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.