Liver transplantation and cell therapies for inborn errors of metabolism.

Liver transplantation is now very successful with >85 % long term survival into adult life. When considering the impact of liver transplantation for metabolic disease two independent factors need to be considered; whether or not the defect causes liver disease and whether or not it is confined to the liver. When considering transplantation many factors need to be considered including the local success of transplantation, the impact of the metabolic disease on the patient and family and the potential for future therapeutic developments. Where transplantation is undertaken for a liver based defect there is a lifelong complete correction of the defect. Where there is a residual extrahepatic defect this will have an impact on the outcome of liver transplantation and the severity of this defect must be considered as part of the transplant assessment process. Access to a multi-disciplinary team with expertise in metabolic disease, liver disease and other relevant organ based specialists is crucial. Most children will receive transplantation from cadaveric donor but living related transplantation from a heterozygote parent is usually safe and effective. Auxiliary liver transplantation has a small but useful role where partial correction of the defect is helpful and there is a future prospect of gene therapy. The first-generation of hepatocyte transplants have shown proof of principle but to date have had a rather modest and temporary metabolic effect. Stem cells may have the potential to produce a more sustained and significant metabolic correction, but must be shown to be effective in controlled trials.