Present at birth
For autosomal recessive disorders, cats with two copies of the variant are at risk of developing the condition. Cats with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their kittens if bred.
At risk cats are likely to show signs of this disease in their lifetime.
Partner with your veterinarian to make a plan regarding your cat’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.
Chediak-Higashi Syndrome (CHS) is a lysosomal disease caused by a mutation in the lysosomal trafficking regulator (LYST) gene which results in the build up of vesicles within cells. Affected cats tend to show partial albinism or hypopigmentation of various degrees, which may not be evident unless compared to non-affected family members. This is due to the build up of atypically sized melanin granules and abnormal distribution of pigment within the skin, which results in a lighter to white coat. Most affected Persian cats express a smoke-blue coat with yellow-green irises or, less commonly, a white coat. As pigmentation is affected in cats, some clinical signs of this disorder are evident at or shortly after birth. Additional clinical signs include photophobia, nystagmus and potential to develop nuclear cataracts as early as three months of age. CHS also causes an increase of granular inclusions in neutrophils which may result in some cats having a higher propensity for bacterial infections. Affected cats also tend to show increased bleeding times due to platelet dysfunction that is most notable after trauma, venipuncture or surgical intervention. In later stages of the disorder, affected cats may show thrombocytopenia.
Therapy is limited to supportive care as dictated by the severity of the clinical signs. Special care should be taken when performing blood draws and other medical procedures due to the propensity for bleeding in affected individuals. When necessary, antifibrinolytic agents (medication promoting blood clotting) should be considered. Affected cats should be monitored closely during and after any required surgical procedure or following any trauma. Owners of affected cats can provide a lifestyle favorable towards reducing risk of trauma and injury to their cat, such as limiting opportunities for falls or the ability to get into fights, and maintaining good dental hygiene to avoid excessive gum bleeding. Keeping affected cats indoors will help to reduce their risk of exposure to infectious diseases and, due to their lack of normal pigmentation, can help protect their eyes and skin from the sun.
There are many responsibilities to consider when breeding cats. Regardless of test results it is important that your cat is in good general health and that you are in a position to care for the kittens if new responsible owners are not found. For first time or novice breeders, advice can be found at most cat registry websites.
This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to be shown. A carrier cat with one copy of the Chediak-Higashi Syndrome mutation can be safely bred with a clear cat with no copies of the Chediak-Higashi Syndrome mutation. About half of the kittens will have one copy (carriers) and half will have no copies of the Chediak-Higashi Syndrome mutation. Kittens in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected kittens. Please note: It is possible that disease signs similar to the ones caused by the Chediak-Higashi Syndrome mutation could develop due to a different genetic or clinical cause.
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Buckley, R. M., Grahn, R. A., Gandolfi, B., Herrick, J. R., Kittleson, M. D., Bateman, H. L., … Lyons, L. A. (2020). Assisted reproduction mediated resurrection of a feline model for Chediak-Higashi syndrome caused by a large duplication in LYST. Scientific Reports, 10(1), 64. View the article