Types of UCDs
There are six different types of UCDs, one for each enzyme in the urea cycle:
- NAGS (N-acetyl glutamate synthetase) deficiency
- CPS 1 (carbamoyl phosphate synthe-tase) deficiency
- OTC (ornithine transcarbamylase) deficiency
- CTLN1 (Citrullinemia type 1, ASD or ASL) deficiency
- ALD (Argininosuccinic Aciduria, ASA, ASL or AL) deficiency
- ARG (hyperargininemia) deficiency
There are also two enzyme transporter deficiencies, which are often considered UCDs:
- HHH Syndrome (ORNT deficiency)
- CTLN2 (Citrullinemia Type II or Citrin deficiency)