Citrullinemia

This code identifies citrullinemia, a rare, inherited metabolic disorder characterized by a deficiency in the enzyme argininosuccinate synthetase (ASS). This deficiency leads to the accumulation of ammonia and other toxic substances in the blood, primarily citrulline, due to impaired function of the urea cycle. The severity can range from severe neonatal onset to milder late-onset forms.

Use this code for patients diagnosed with any type of citrullinemia, including Type I (classic) and Type II (citrin deficiency). Documentation should clearly indicate the diagnosis of citrullinemia, often confirmed by elevated plasma citrulline levels and genetic testing. This code is appropriate for both initial diagnosis and ongoing management of the condition.

• Ensure documentation specifies the type of citrullinemia if known, although this code covers all forms.
• Consider co-reporting with codes for associated neurological complications (e.g., encephalopathy) or liver disease, if present.
• This code is distinct from other urea cycle disorders; verify the specific enzyme deficiency before assigning.