I was pretty sure that Urea Cycle is a genetic disorder in which is caused by a deficiency of a certain enzyme which is what eliminates ammonia in the blood.

NItrogen is the waste product of protein metabolism which would be converted to Urea then normally formed into urine and wasted.

When a person has a Urea Disorder the nitrogen accumilates as ammonia. In large amounts is extremely toxic. Because the enzyme isn't doing it's job at all. When dealing with this type of situation, the ammonia is not released in the waste causing permanent brain damage and even death.