[MIM 237,300]

Estimated prevalence at 1/62,000. Autosomal recessive transmission of a mutation of the CPS1 gene (2q35). Severe and rare disorder of the metabolism of the urea cycle, most commonly characterized either by severe hyperammonemia of neonatal onset, occurring several days after birth manifesting as lethargy, vomiting, hypothermia, convulsions, coma and death, or by late presentation in childhood or adulthood, with milder symptoms and signs of hyperammonemia.

Carbamyl phosphate synthetase II (CAD gene (2p23.3)) is an ubiquitous cytoplasmic protein involved in the metabolism of pyrimidines.

Anesthetic implications: 

see urea cycle. Shorten the duration of preoperative fasting: administer a glucose-containing solution as soon as the fasting period begins. Empty the stomach to avoid any hidden protein intake through the digestive tract in case of surgery where blood can be swallowed (ENT, stomatology). Special monitoring: NH4  (nl < 50 µmol/L), blood glucose. Use an anesthesia strategy that reduces the stress response: locoregional anesthesia, opioids, optimal postoperative analgesia.

References : 

-         Dobbelaere D, Mention K.
Déficits du cycle de l’urée in  Maladies métaboliques héréditaires, éditeurs B Chabrol et P de Lonlay,
Progrès en pédiatrie n°29, p139-147, Doin 2011

-        Del Rio C, Martin-Hernandez E, Ruiz A, Quijada-Fraille P, Rubio P.
Perioperative management of children with urea cycle disorders.
Pediatr Anesth 2020; 30:780-91.

-        Matsushita H, Fujiyoshi T, Yoshimaru K, Matsuura , Mushimoto Y, Karashima Y,  Yamaura K.
Anesthesia management in living‑donor liver transplantation in a patient with carbamoyl phosphate synthetase deficiency: a case report.
JA Clinical Reports 2022 ;  8:71   doi.org/10.1186/s40981-022-00558-9

Updated: July 2023