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Dihydropyrimidinase Deficiency

Dihydropyrimidinase Deficiency is a condition that causes tiredness, weakness, vomiting, and high levels of ammonia in the blood.

Key Signs

Depression, Weakness, Vomiting

Age of Onset

0 to 2 yrs

Juvenile onset


Autosomal Recessive

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.

Likelihood of the Condition

High likelihood

At risk cats are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a cat with DHP

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.

For Veterinarians

Here’s what a vet needs to know about DHP

Dihydropyrimidinase (DHP) Deficiency is a rare metabolic syndrome characterized by dihydropyrimidinuria. The DHP enzyme is utilized in various metabolic pathways, including the breakdown of pyrimidine bases (uracil and thymine) as well as certain drugs. The disease causes the substrates of this enzyme to accumulate in the body. These substrates are also seen in the urine of affected cats. Clinical signs of the disease include lethargy, weakness, vomiting, and hyperammonemia. These clinical signs worsen when the cat is fed a high-protein diet. Affected cats may also show signs of malabsorption and malnutrition.

The condition can be partly managed through feeding a low-protein diet and the importance of diet management should be emphasized to owners.

For Breeders

Planning to breed a cat with this genetic variant?

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

Technical Details

Variant G>A
Chromosome F2
Coordinate 52,064,442

All coordinates reference FelCat9.0

References & Credit

Credit to our scientific colleagues:

Chang HS. et al. (2012) Dihydropyrimidinase Deficiency: The First Feline Case of Dihydropyrimidinuria with Clinical and Molecular Findings. In: SSIEM (eds) JIMD Reports - Case and Research Reports, 2012/3. JIMD Reports, vol 6. Springer, Berlin, Heidelberg. View the article