Liver transplantation as treatment for neurological disorders

Liver transplantation has been performed for patients with incurable liver diseases but this therapeutic technique can be extended to neurological disorders, such as familial amyloid polyneuropathy and adult-onset type II citrullinemia. An amyloid precursor in familial amyloid polyneuropathy, a variant form of transthyretin, is produced mainly in the liver. After liver transplantation, it has been shown that this amyloid precursor disappears from the sera of patients once progression of the disease has halted. Type II citrullinemia is caused by a deficiency of liver-specific argininosuccinate synthetase activity and shows various neurological manifestations closely resembling those of hepatic encephalopathy, resulting in fatal outcome. All metabolic abnormalities in this disease, which include elevated plasma concentrations of citrulline and ammonia, can be immediately corrected by liver transplantation.