Pathogenic in ClinVar;see sidebar on main SNP page. This is a genotype with recommended actions if clinically confirmed. In brief:
- CTLN2 can appear suddenly in children or adults as recurrent hyperammonemia with neuropsychiatric symptoms.
- To prevent hyperammonemia a diet rich in protein and lipids and low in carbohydrates is recommended. Diet composition consultation and a medical genetics consultation are recommended. However, the effectiveness of dietary treatment prior to the onset of symptoms of CTLN2 is unknown.
- Alcohol, acetaminophen and rabeprozole may trigger CTNL2.
- Arginine and sodium pyruvate administration may be effective in preventing hyperammonemic crises (by reducing blood ammonia concentrations) and fatty liver, thereby delaying the need for liver transplantation.
- Liver transplantation is the most successful therapy to date for symptomatic patients. More recently, some reports indicate that arginine and sodium pyruvate administration combined with a carbohydrate-restricted diet may be an effective therapy.
- Should severe brain edema occur, avoid treatment with glycerol-containing osmotic agents.
- Determining the genetic status of at-risk relatives could allow an infant's diet to be managed for citrin deficiency before symptoms occur.
The full ClinGen Actionability report about adult-onset type II citrullinemia (CTLN2) can be found here.
Genetic counseling may be available to you through your health-care network. In the US, genetic counselors may be found via this webpage of the National Society of Genetic Counselors.