Liver transplantation versus conservative treatment for adult-onset type II citrullinemia: our experience and a review of the literature.

Adult-onset type II citrullinemia (CTLN2), an autosomal recessive disorder caused by a mutation in the SLC25A13 gene, is characterized by increased serum citrulline and ammonia levels. Patients with CTLN2 also display various neuropsychiatric symptoms. Many individuals with CTLN2 are fond of protein-rich and/or lipid-rich foods with an aversion to carbohydrate-rich foods. We herein report two cases of CTLN2 treated with living donor liver transplantation (LDLT) and provide a review of the pertinent literature. Case 1 was a 43-year-old man admitted to our hospital for repetitive episodes of consciousness disturbance. Case 2 was a 37-year-old man admitted to our hospital because of abnormal behavior associated with hyperammonemia. A definitive diagnosis of CTLN2 was accomplished by DNA analysis in both patients, who successfully underwent LDLT using liver segments from donor siblings with confirmed heterozygous gene expression. Case 2 also underwent conservative therapy with arginine and a high-fat, carbohydrate-restricted diet prior to LDLT. Postoperative recovery was uneventful and food was unrestricted in both patients. We also identified 77 cases of CTLN2 in the literature and reviewed them in terms of outcome of both liver transplantation and conservative therapy. The survival rate in patients treated by liver transplantation was 100%, whereas that in patients treated by conservative treatment showed improvement from 39.5% to 76.5% over the years. Liver transplantation is a practical treatment that fundamentally improves patient quality of life after transplantation. However, recent studies have suggested that arginine and sodium pyruvate administration combined with intensive nutritional support is also an effective therapy for CTLN2. Further development of conservative therapy may provide a safer, more affordable alternative to liver transplantation in the near future.