Heterozygous liver transplantation for maple syrup urine disease: First European reported case.

MSUD is an autosomal recessive metabolic disorder that results from a defect in the BCKDH enzyme. This enzyme is essential for the second step in the metabolism of the branched-chain amino acids, leucine, isoleucine, and valine. Patients with MSUD are subject to severe, irreversible neurologic injury unless closely managed with a specialized metabolic formula and a diet restricted in leucine throughout their lifetime. During times of illness, patients with MSUD can suffer from severe metabolic derangement, acute cerebral edema, and untimely death. Deceased donor liver transplant restores the ability to metabolize branched-chain amino acids, even on an unrestricted diet, and prevents metabolic derangements during times of illness. We report a successful case of living donor (parental) transplant for a child with MSUD. The donor was the child's father. This approach has been controversial as parents of children with MSUD are obligate heterozygotes for the condition and have diminished levels of BCKDH activity. If effective, living-related donor transplant provides a promising alternative for deceased donor liver transplant, which often requires a prolonged waiting period and may not be feasible in areas with limited medical resources.