A urea cycle disorder occurs when the body can’t break down the ammonia that amino acids produce.
Unchecked, ammonia is toxic.
According to the National Urea Cycle Disorders Foundation, there are six different types of urea cycle disorders:
- Carbamyl Phosphate Synthetase (CPS1)
- N-Acetylglutamate Synthetase (NAGS)
- Ornithine Transcarbamylase (OTC deficiency)
- Argininosuccinic Acid Synthetase (AS)
- Argininosuccinate Lyase (AL)
- Arginase (AG)
The level of severity of each type varies greatly from patient to patient. Some infants develop enzyme deficiencies prior to birth. As a result, they can become very ill within their first 48 hours of life, which is another reason for newborn screening.
Urea cycle disorders aren’t just prevalent in babies; adults can also have them. But many people go undiagnosed because their bodies can remove enough ammonia to prevent sickness. I say this with a caveat, however. When an adult begins to have excessive ammonia building up on the brain, they can become disoriented, combative, and even fall into a coma.
It’s a good idea—if you are with someone who is in an emergency situation—to ask to have a blood ammonia test administered.
Treatment for urea cycle disorders include dietary management, medications, and in some cases, a liver transplant.
Some children have difficulty eating, because the level of serotonin in their brains suppresses their appetite. This is when working with the child’s healthcare team really pays off. A feeding tube can make a big difference, but there are also medications that can help to stimulate the appetite.