Do Chimera Cats Have Health Problems?

In mythology, a chimera is a hybrid creature usually depicted as a mix between a lion, goat, and serpent in Greek mythology. In real life, chimerism can be found in humans and other animals, though they’re not as scary as the fire-breathing monster of ancient lore. You may have even met a chimera (or be one yourself) without knowing it, since genetic testing is the only way to know for sure if someone is a chimera.

Chimera cats contain two sets of DNA. This occurs when two embryos merge within the mother's womb. Their DNA can be

For some kittens, their chimera status is suspected from birth due to their unique 'split face' colouring and different eye colours. For others, the external signs are so subtle that they are never detected. Genetically, speaking they will be XY/XY, XX/XX or XY/XX depending on the sex of each of the fused embryos.

Chimeras should not be confused with cats who have Klinefelter's Syndrome. This is a condition whereby male cats have XXY sex chromosomes.

There is very limited data available regarding the health of a feline chimera. In humans, we know that chimerism can be linked to certain autoimmune disorders as well as infertility.

However, when it comes to those with Klinefelter's Syndrome, we are aware of the many consequences to the affected cat's health.

Unfortunately, because of their unique XXY configuration, male calico and tortoiseshell cats can develop specific health conditions and shorter lifespans. Some of the issues associated with XXY syndrome, as it is sometimes called, include cognitive and developmental problems, reduced bone mineral content, and increased body fat.

Of course, it’s still possible for male cats with Klinefelter syndrome to live a happy life, but they likely require special care. Here’s an overview of some of the conditions that may affect chimera cats. 

Cognitive dysfunction

Cognitive dysfunction in cats is similar to Alzheimer’s disease and senile dementia in humans. The behavioral signs, which start to become more noticeable at around 10 years of age, include: 

• Wandering into unfamiliar territory
• Spatial disorientation
• Going outside the litter box
• Excessive sleeping
• Staring blankly at walls or into space for long periods

Since there is no cure for cognitive dysfunction, the focus should be on making your cat’s environment as comfortable as possible and promoting cognitive function. Treatment can include:

• Adding litter boxes that are easy to access
• Providing exercise and new toys
• Maintaining the same daily routine
• Placing nightlights throughout the house
• Supplements approved by your veterinarian

Bone fractures

Reduced bone mineral content can increase your cat’s risk for broken bones. Bone fractures in cats are usually caused by fights, falls, or car accidents, with the jaw, femur, pelvis, and tail being some of the most common sites. Signs of a fracture include:

• Pain
• Swelling
• Lameness

Treatment depends on the type of fracture and the cat’s age and health. It may include: 

• External splints or casts
• Bone plates, screws, or pins
• Antibiotics
• Pain relievers
• Physical therapy

Obesity

Excess fat can negatively impact your cat’s daily life and longevity. Obesity in cats can be caused by several factors, including: 

• Age 
• Diet
• Lack of activity
• Medical conditions, such as Klinefelter syndrome 

Felines with increased body fat have a higher risk of developing:

• Osteoarthritis 
• Heart disease
• Hypertension
• Diabetes mellitus
• Urinary bladder stones
• Many types of cancer

Treating obesity in cats should always be done under the supervision of a professional, as dropping pounds too quickly can lead to other problems. Your vet will likely put together a weight loss plan that includes:

• Specific nutritional products
• Portion control
• Physical activity 
• Medication, if needed

Some chimeras are fertile, while others are not. It depends on their specific DNA.

When it comes to male calicos and torties, they are usually sterile. While it’s possible for them to be fertile, it’s more often the case that they’re not. Sterile male cats should still be neutered, however, as this procedure can protect them from testicular cancer and prevent unwanted territorial spraying. 

Every cat is special, and even more so if they’re a chimera cat or cat with Klinefelter's Syndrome. Caring for a feline who requires extra TLC can be costly — if you suspect that your furry friend is at risk of developing any of the above conditions, check out our pet insurance comparison tool. The sooner you insure your cat, the more protection you’ll have from unexpected vet costs.