Liver transplantation from a live donor to a patient with maple syrup urine disease: Two case reports

Genetic analysis by targeted next-generation sequencing and novel variation identification of maple syrup urine disease in Chinese Han population

Maple syrup urine disease (MSUD) is a rare autosomal recessive disorder that affects the degradation of branched chain amino acids (BCAAs). Only a few cases of MSUD have been documented in Mainland China. In this report, 8 patients (4 females and 4 males) with MSUD from 8 unrelated Chinese Han families were diagnosed at the age of 6 days to 4 months. All the coding regions and exon/intron boundaries of BCKDHA, BCDKHB, DBT and DLD genes were analyzed by targeted NGS in the 8 MSUD pedigrees. Targeted NGS revealed 2 pedigrees with MSUD Ia, 5 pedigrees with Ib, 1 pedigree with MSUD II. Totally, 13 variants were detected, including 2 variants (p.Ala216Val and p.Gly281Arg) in BCKDHA gene, 10 variants (p.Gly95Ala, p.Ser171Pro, p.Phe175Leu, p.Arg183Trp, p.Lys222Thr, p.Arg285Ter, p.Arg111Ter, p.S184Pfs*46, p.Arg170Cys, p.I160Ffs*25) in BCKDHB gene, 1 variant (p.Arg431Ter) in DBT gene. In addition, 4 previously unidentified variants (p.Gly281Arg in BCKDHA gene, p.Ser171Pro, p.Gly95Ala and p.Lys222Thr in BCKDHB gene) were identified. NGS plus Sanger sequencing detection is effective and accurate for gene diagnosis. Computational structural modeling indicated that these novel variations probably affect structural stability and considered as likely pathogenic variants.

Hyperleucinosis during infections in maple syrup urine disease post liver transplantation

Maple syrup urine disease (MSUD) is due to biallelic variants in one of the three genes: BCKDHA, BCKDHB, and DBT. Branched-chain alpha-ketoacid dehydrogenase complex deficiency and elevated leucine, valine, isoleucine and alloisoleucine in body fluids are the results. We report hyperleucinosis during intercurrent illnesses in six patients with MSUD post liver transplantation. Patient charts were retrospectively reviewed. Data was entered into an Excel Database. Literature was reviewed. Six patients with MSUD were included who had post liver transplantation hyperleucinosis during an intercurrent illness. Five had encephalopathy. One received hemodialysis for the management of hyperleucinosis. All patients had unrestricted diet. Additionally, there were five patients (one patient included into the current study) reported in the literature. We suggested management considerations for the follow-up of patients with MSUD post liver transplantation after the first episode of unexplained encephalopathy or signs of acute hyperleucinosis during intercurrent illness due to our clinical experience: 1) Healthy: Unrestricted diet and monitoring of leucine levels; 2) Illness: a) home illness management: increased carbohydrate intake b) illness management at hospital: intravenous dextrose, intravenous lipid and daily plasma amino acid monitoring. We report hyperleucinosis and/or encephalopathy as a rare event post liver transplantation in MSUD as a multicenter case series. Hyperleucinosis and/or encephalopathy may occur in both related and unrelated donor liver transplantation. Based on the long-term follow-up of those patients, these suggested management considerations may be revised as per the patients' needs.

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Patients with MSUD can present with hyperleucinosis during intercurrent illness post liver transplantation.

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Hyperleucinosis in MSUD post liver transplantation can occur in related and unrelated donor liver transplantation.

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Monitoring of patients with MSUD is required after their first episode of hyperleucinosis post liver transplantation.

Living Related Liver Transplantation for Metabolic Liver Diseases in Children

ABSTRACT

Metabolic liver diseases (MLDs) are a heterogeneous group of inherited conditions for which liver transplantation can provide definitive treatment. The limited availability of deceased donor organs means some who could benefit from transplant do not have this option. Living related liver transplant (LrLT) using relatives as donors has emerged as one solution to this problem. This technique is established worldwide, especially in Asian countries, with shorter waiting times and patient and graft survival rates equivalent to deceased donor liver transplantation. However, living donors are underutilized for MLDs in many western countries, possibly due to the fear of limited efficacy using heterozygous donors. We have reviewed the published literature and shown that the use of heterozygous donors for liver transplantation is safe for the majority of MLDs with excellent metabolic correction. The use of LrLT should be encouraged to complement deceased donor liver transplantation (DDLT) for treatment of MLDs.