Carbamoyl Phosphate Synthetase 1 Deficiency a.k.a. Hyperammonemia

What is carbamoyl phosphate synthetase 1 deficiency?

Carbamoyl phosphate synthetase 1 deficiency, which is also called hyperammonemia, is an inherited condition characterized by high accumulations of ammonia in the blood. This ammonia is created when the body breaks down proteins in the liver; typically, the excess nitrogen created in this process is flushed out of the body as part of the urea cycle. The carbamoyl phosphate synthetase 1 gene creates an enzyme that helps regulate this excessive nitrogen production, so people with a carbamoyl phosphate synthetase 1 deficiency have either low levels of the enzyme or no enzyme at all. Thus, the excess nitrogen builds up in the bloodstream as toxic ammonia. If the ammonia level becomes too high, it can cause serious problems like seizures, coma, swelling of the brain, or developmental disabilities; left untreated, it can cause death.

Who gets carbamoyl phosphate synthetase 1 deficiency?

Carbamoyl phosphate synthetase 1 deficiency primarily affects infants, although people can be diagnosed later. Because it’s most prevalent in newborns, it can be difficult to detect; the condition’s rarity also complicates diagnosis. Carbamoyl phosphate synthetase 1 deficiency is an autosomal recessive pattern genetic disease—meaning each parent carries a copy of the defective carbamoyl phosphate synthetase 1 gene, but don’t themselves show any signs or symptoms. As of now, there aren’t any definitive numbers for the prevalence of carbamoyl phosphate synthetase 1 deficiency.

What are the symptoms of carbamoyl phosphate synthetase 1 deficiency?

Carbamoyl phosphate synthetase 1 deficiency symptoms typically occur within the first few days after birth, and can range from the difficult to detect (sleepiness) to the very obvious and serious (seizures). Be on the lookout for:

Unusual sleepiness
Difficulties breathing
Getting cold easily
Problems feeding
Vomiting after feeding
Unusual or uncontrolled body movements
Seizures
Coma

How is carbamoyl phosphate synthetase 1 deficiency diagnosed?

It’s critical for infants showing symptoms to have a carbamoyl phosphate synthetase 1 deficiency diagnosis made as soon as possible. As part of the standard newborn screening, doctors look at the carbamoyl phosphate synthetase 1 range—if the numbers are abnormal or out of range, follow-up tests will be ordered to determine if the original tests were incorrect or to confirm a diagnosis. Follow-up tests involve checking both blood and urine samples for high levels of acids and toxins. Doctors may also run genetic tests, a liver biopsy, an MRI, or CT scan.

What treatments are available for carbamoyl phosphate synthetase 1 deficiency?

Carbamoyl phosphate synthetase 1 deficiency treatment focuses on techniques to reduce ammonia in the body. In some cases, this is accomplished by dialysis or medications that provide different “pathways” for clearing extra ammonia. Beyond these, the chief form of regulating ammonia waste on a daily basis is to reduce protein in the diet. Doctors can provide low-protein formula for infants and toddlers, and work with new parents to create a strict low-protein diet that balances getting enough protein for healthy growth without causing additional symptoms. People with carbamoyl phosphate synthetase 1 deficiency also need to avoid infections and stress, because these can speed up the process of breaking down proteins in the body.