Amyloidosis in Cats

Although amyloidosis has various recognized causes, this feline disease is well known as a familial trait in Siamese and Abyssinian cat breeds. A high percentage of Siamese oriental feline breeds have been reported to have Amyloidosis affecting the liver, whereas Amyloidosis has been shown to affect the kidneys in Abyssinian oriental breeds. Cats often develop this protein disease between one to five years of age, but the progression of the disease can come on rapidly or progress over several years. The mode of inheritance of Amyloidosis is unknown, so it is therefore recommended that affected felines be removed from breeding practices.

Amyloidosis is the term veterinarians use to describe an abnormal deposit of the protein complex known as amyloid into the organs and tissues of a feline. The deposit of amyloid disrupts the cat’s organ function, which leads to failure of said organ and eventual death. Amyloidosis is classified based on the type of amyloid protein involved, with AA amyloids and AL amyloids being the most common in feline amyloidosis disease. AA amyloids are known to deposit into the kidneys, liver and spleen, resulting in cancer, chronic bacterial infections, or inflammatory disease. AL amyloids are known to deposit themselves in the joints and nerve tissues of the feline, causing neurological damage.

The symptoms of Amyloidosis in cats are related to the progressive damage of the internal organ the deposited proteins are affecting. Amyloid proteins are a misfolded, complex protein, which means they are difficult for the body to break down and use like other proteins in the body. Over time, the deposited proteins build up, displacing normal organ tissues and disrupting the subjected organ’s vital function. The organ enlarges, inflames and becomes damaged, resulting in fatal organ failure. Symptoms of amyloidosis in cats are linked to the specific organ affected and can include: 

• Kidney amyloid accumulation: Chronic kidney disease 
• Liver amyloid accumulation: Hepatomegaly, Liver rupture, Internal bleeding 
• Weight loss
• Anorexia 
• Lethargy
• Polyuria 
• Polydipsia 
• Poor hair coat 
• Dehydration 
• Depression 
• Weakness 
• Abdominal pain 
• Diarrhea 
• Vomiting 

Amyloidosis in cats is a disease caused by misfolded, complex proteins known as amyloids that cannot be absorbed by the body. The abnormal protein structure is believed to be a result of an abnormal gene mutation, a hereditary disorder present in the bloodline of feline family trees. The nature of the genetic mutation as well as the inheritance of this feline disorder is yet to be discovered. Siamese and Abyssinian feline breeds have a high reported rate of developing the disease, although this condition is rather rare. Additional factors that may play in the role of developing amyloidosis in cats are infectious disease and the environment in which the feline lives.

Amyloidosis in cats is difficult to differentiate from other feline diseases. Organ failure, infection of the organ, and disease of the kidneys, liver, spleen and accompanying organs can all mimic the clinical signs associated with amyloidosis. Plus, amyloidosis is rarely reported in veterinary medicine and is less likely to be the cause of the feline’s condition than common organ conditions known to affect cats. However, Amyloidosis may be suspected by your veterinarian if the feline has been experiencing chronic infection. Additionally, the majority of felines that are admitted to the veterinary clinic are already displaying clinical signs, which means that amyloid protein deposits have already caused severe damage to the feline’s organ. Clinical signs soon turn fatal and the diagnosis of amyloidosis is often made post-mortem. The biopsy will reveal amyloid protein deposits in one of the affected organs as a confirmative diagnosis.

There is no known treatment of amyloidosis in cats, or any other species for that matter. No medication has been found to allow the feline’s body to absorb or breakdown the complex, mutated amyloid proteins to prevent organ deposit buildup. There is also no true prevention method of amyloidosis, but as infection and environmental factors are believed to be a possible cause, overall healthy cats will be less likely to develop this fatal disease.There is no known treatment of amyloidosis in cats, or any other species for that matter. No medication has been found to allow the feline’s body to absorb or breakdown the complex, mutated amyloid proteins to prevent organ deposit buildup. There is also no true prevention method of amyloidosis, but as infection and environmental factors are believed to be a possible cause, overall healthy cats will be less likely to develop this fatal disease.

Genetic laboratories are working to develop genetic testing for Siamese and Abyssinian cat breeds against amyloidosis, but a genetic test for identification is currently unavailable. Further genetic testing and research will allow experts to develop a screening tool for this hereditary disorder, but in the meantime, it is highly recommended to remove affected feline from its breeding program. Parents, siblings, offspring, and grandparents should all discontinue breeding practices if one of the feline family members has been diagnosed with amyloidosis.