An<unk>  or<unk><unk>  defect is a genetic<unk>  caused by a deficiency of one of the enzymes in the<unk><unk>  which is responsible for removing ammonia from the blood stream. The<unk><unk>  involves a series of biochemical steps in which nitrogen, a waste product of protein metabolism, is removed from the blood and converted to<unk> . Normally, the<unk>  is transferred into the urine and removed from the body. In<unk> s, the nitrogen accumulates in the form of ammonia, a highly toxic substance, and is not removed from the body.<unk> s are included in the category of inborn errors of metabolism. There is no cure.
Urea cycle disorder
Homocystinuria
Mevalonic aciduria
Phenylketonuria
Ornithine transcarbamylase deficiency
Essential fructosuria
Argininemia
D-Glyceric acidemia