A urea cycle disorder is a rare genetic disorder caused by a deficiency of one of the six enzymes in the urea cycle, which is responsible for removing ammonia from the blood stream. The urea cycle involves a series of biochemical steps in which nitrogen, a waste product of protein metabolism, is removed from the blood and converted to urea. Normally, the urea is transferred into the urine and removed from the body. In a person with a urea cycle disorder, the nitrogen accumulates in the form of ammonia, a highly toxic substance, and is not removed from the body – resulting in hyperammonemia. Ammonia then reaches the brain through the blood, where it causes irreversible brain damage, coma and/or death.
Urea cycle disorders are included in the category of inborn errors of metabolism. There is no cure.
