How PRA (Progressive Retinal Atrophy) Affects Bengal Cats
Progressive retinal atrophy refers to a group of genetic disorders that cause degeneration and atrophy or wasting away of the retina – a layer of light-sensitive cells located at the back of the eye.
It can lead to a continuous decline in the quality of vision and even result in blindness.
A form of retinal atrophy that is suspected to be hereditary was discovered in Bengal cats.
Clinical signs usually become evident at around seven weeks and slowly progresses so that by two years of age, compromised vision is apparent. Most of these cats become blind by around three to five years of age.
Some affected cats may not show clinical signs but, eventually become blindness later in life.
You may become aware of this condition in your own cat when its vision becomes extensively impaired. For instance, you may notice your affected cats bump into things and also show signs of having difficulties seeing at night.
Their eye pupils are usually more dilated than those of normal cats in the same lighting conditions.
This article will help you understand how PRA affects the cats, how to identify affected and carrier cats, and ways to manage the gene in carriers.
Occurrence of PRA in Bengal Cats
Progressive retinal atrophy is caused by a single nucleotide mutation in the gene known as CEP290. The gene produces a mutant cellular protein that inflicts the fetus during development.
This gene also targets the retina’s rods and cones, which reflect light and provide the ability to see. The condition inherited as an autosomal recessive trait, which means that two copies of the defective gene have to be present in a cat for it to suffer from the disease.
Cats with only one copy of the mutant gene (heterozygous cats) are known as carriers as they have normal vision but can pass the mutation to their offspring.
Those with two copies of the defective gene (homozygous cats) develop retina degeneration and atrophy that progresses to blindness.
The mutant DNA variant appears to be common among the Bengal breed and can be traced back to a famous lineage of Bengals from a few decades ago.
Retinal Degeneration Risk Factors
Many Bengal cats are at risk of having this disease.
It is expected that these cats worldwide are in danger of this hereditary condition.
Since it inherited, it is not gender-specific – both male and female kittens are at risk of possessing the gene mutation. The disorder can be clinically examined through a DNA test or by an eye exam before the breeding age.
However, heterozygous cats that only have one copy of the mutant gene can only be tested for blindness through DNA examination.
If you have a Bengal cat, therefore, it is essential to have it checked for progressive degeneration so that you can protect its offspring if it is a carrier.
Signs of Progressive Retinal Atrophy
If you suspect that your cat may be having the disorder, it is essential to see a vet for clinical testing. However, certain signs indicate a cat is undergoing retinal atrophy.
First, the cat may tend to look disoriented and unaware of its surroundings. Since the condition begins to manifest at around seven weeks, it is easy to notice a change in the cat’s behavior.
Other common signs include the following:
- Cat becomes vocal and more attached to the owner
- Pupil dilation and increased tapetal reflex
- Nervousness around other pets
- Visual deflect during the night
An affected cat can still sense where they are going.
The cat will still be able to find the litter tray, feeding bowls, and bed. They may even be able to jump onto things like before they suffered blindness.
Once the affected cat familiarizes itself with its surroundings, it becomes mobile and active once more even with poor vision quality or total blindness.
It is critical for the cat to be tested so that you can determine the extent of the condition and provide better care.
Retinal Atrophy Testing
As mentioned earlier, progressive retinal degeneration in Bengals can be tested through DNA examination meant to identify rdAc. The results may take between two and seven days depending on the clinic.
This is the most efficient test as compared to eye examination if you are uncertain whether the cat is a carrier.
There are three possible results from the testing:
- A clear result which indicates that the cat does not have the rdAC genetic mutation. This shows that the cat does not suffer from retinal atrophy unless it occurs in future due to other unidentified genetic mutations.
- A homozygous result which indicates that the cat has two copies of the rdAc genetic mutation. In this case, the Bengal cat will suffer progressive degeneration of the retina.
- A heterozygous result which shows that the cat has one copy of the mutant gene and does not suffer from the condition. However, the gene is recessive and can be passed on to the offspring.
The gene test is not only critical for determining the health of your cat, but it can also help identify the cats that should be bred.
It is recommend that two homozygous cats not be used for breeding as they will produce offspring with the gene mutation.
Two carriers are likely to produce 25 percent affected cats, while a normal and heterozygous one will provide 50 percent healthy and 50 percent carrier Bengals. The best cats for breeding, in this case, are a carrier and a normal one.
Treatment for Retinal Degeneration
Progressive retinal atrophy is not curable, and no medication can slow down or prevent the gene mutation in homozygous cats.
The generation process occurs due to mutated DNA, which cannot be easily accessed as it is part of the genetic makeup.
Your vet may advise that you spay or neuter an affected kitten to prevent passing on of the gene to offspring. Ideally, it is not advisable for affected cats to be involved in breeding programs.
Home Care for Affected Cats
If you find that your kitten is progressively losing its vision, it is suitable to create a comfortable and ideal environment.
Cats that are used to their surroundings can function normally. And, for this reason, it is important to avoid making major changes around the home.
This way, you can protect the cat from having mishaps by bumping into things and falling into dangerous spots or even in a bath full of water.
Take special care so that the cat doesn’t go near a busy road where it can be easily knocked.
Restrict its movement to the house, backyard, and garden. If you don’t have a fence, invest in one to protect it from straying outside the home.
With time, the cat will adapt to the vision changes and lead a full and active life just like other regular pets.
What to Do with a Carrier
Carriers lead a normal life as do other healthy cats, and they do not show signs of progressive degeneration of the retina.
If you wish to use your carrier Bengal for breeding, it should be mated with a healthy cat as the resultant kittens will not be affected by the condition.
Although, they will be carriers of the defective gene, and a DNA test can confirm this.
All future breeding should occur with normal cats as two carriers are likely to produce kittens with the condition.
It is essential to have your kitten tested before the breeding age so that you can avoid more offspring with the disorder.
It is recommend that you do this at around six or seven months, which is when the first signs of deterioration in vision quality occur.
The veterinary doctor will recommend a DNA test over an eye exam as some cats don’t show clinical signs of retinal degradation until after five years.
Other Causes of Vision Loss
It is important to note that retina degeneration as a result of gene mutation is not the only reason for poor vision or loss of the ability to see in kittens.
Exposure to certain antibiotics for a prolonged period has also been associated with retinal atrophy. Look out for medication that contains a substance known as enrofloxacin.
Also, nutritional deficiency, particularly the lack of amino acid taurine can also cause deterioration in vision.
Retinal atrophy that’s caused by medication and poor diet can be treated or prevented by avoiding exposure to these antibiotics and providing a balanced diet for the cat.
Diagnosis of retinal generation in your Bengal cat should not be a cause for worry.
Since Bengal cats are sensitive pets, they eventually familiarize themselves with their surroundings even in a blind state and lead a normal life.
It is essential to show care and find ways to make life easier for the pet as it adjusts to the loss of vision.
You can seek advice from a veterinarian on how to provide quality care and protection to your affected cat.
