Citrullinemia type I

Citrullinemia type I (CTLN1) is an inherited disease characterized by poor growth, vomiting, spasticity, increased intracranial pressure, and neurologic disorders. It involves defects in an enzyme called argininosuccinate synthase. This enzyme is important for breaking down nitrogen (found in proteins) so that it does not build up as ammonia. The symptoms of CTLN1 are due to the toxic accumulation of ammonia and other substances, particularly in the liver and nervous system. Citrullinemia type I is also known as argininosuccinate synthetase deficiency or citrullinuria. View testing options