Lipoprotein Lipase Deficiency (also called chylomicronemia) results from a deficiency of the lipoprotein lipase enzyme. Lipoprotein lipase is crucial in lipoprotein and lipid metabolism. Deficiency of this enzyme leads to impaired uptake and use of fatty acids for energy metabolism. Clinical signs of the disease can be observed in some cats at birth and are, otherwise, often noticeable before one year of age. Affected kittens may show reduced birth weight and slow growth rates, while adults have reduced body mass and body fat. Affected queens may also have an increased number of stillborn kittens. Additional clinical signs include lethargy, anorexia, and xanthomata (lipid granulomas in the skin and internal organs). More severely affected individuals may show various neuropathies (such as facial paralysis, Horner's syndrome, radial and/or tibial nerve paralysis) and lipemia retinalis. Less commonly seen clinical signs include anemia and splenomegaly. Most affected individuals will have a fasting hyperchylomicronemia. Lipoprotein analysis of affected cats will show elevated triglyceride levels, even when fed a low fat diet; a finding that can be shared with some carriers of this mutation. Total cholesterol and HDL-cholesterol ratio is also elevated in affected cats.

Transitioning to a low-fat, high-fiber diet is considered the cornerstone of therapy, although not all individuals respond. Additional therapies are limited to supportive care (such as medication for pain when warranted) and treating any secondary disorders that may arise.

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 LLD mutation can be safely bred with a clear cat with no copies of the LLD mutation. About half of the kittens will have one copy (carriers) and half will have no copies of the LLD 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 LLD mutation could develop due to a different genetic or clinical cause.