Heterozygote to homozygote related living donor liver transplantation in maple syrup urine disease: a case report

Evaluation of living donors for hereditary liver disease (siblings, heterozygotes)

Living donor liver transplantation (LDLT) is recognised as an alternative treatment modality to reduce waiting list mortality and expand the donor pool. Over recent decades, there have been an increasing number of reports on the use of LT and specifically LDLT for familial hereditary liver diseases. There are marginal indications and contraindications that should be considered for a living donor in paediatric parental LDLT. No mortality or morbidity related to recurrence of metabolic diseases has been observed with heterozygous donors, except for certain relevant cases, such as ornithine transcarbamylase deficiency, protein C deficiency, hypercholesterolemia, protoporphyria, and Alagille syndrome, while donor human leukocyte antigen homozygosity also poses a risk. It is not always essential to perform preoperative genetic assays for possible heterozygous carriers; however, genetic and enzymatic assays must hereafter be included in the parental donor selection criteria in the aforementioned circumstances.

Long-term results of liver transplantation for maple syrup urine disease: A single-center experience in Turkey

OBJECTIVES

Maple syrup urine disease (MSUD) is an autosomal recessive inherited disorder. Despite the advances in medical nutrition therapies, classical phenotype causes severe neurological disorders and sudden death. It is known that MSUD patients do not experience metabolic attacks despite their free diet after liver transplantation (LT). This study aims to reveal the long-term results, development, mental, motor, intellectual and nutritional status of MSUD patients who underwent LT.

METHODS

The data of 12 patients who underwent deceased donor (5 recipients) and living donor liver transplantation (7 recipients) were retrospectively analyzed. The age, genotype, psychometric and mental status, development, BCAA values, type of LT, donor-recipient proximity, complications, and survival were assessed.

RESULTS

There were 4 (33%) girls and 8 (67%) boys. The mean current age was 9.33 ± 4.58 years. The mean follow-up time was 3 ± 2.5 years. The repeated measures of leucine and isoleucine values revealed that there were no significant differences from the pre-LT to post-LT 1-year. The protein-restricted nutrition was switched to a free diet when oral intake was opened after LT. None of the recipients experienced metabolic attacks after the living donor or deceased donor LT. The 1-, 3-, and 5-year survival rate of the patients is 83.3%. There was no significant difference in survival between living and deceased donor liver transplantation.

CONCLUSIONS

Liver transplantation is a treatment option for MSUD in proper conditions to save the patient life, increase the quality of life, and provide essential amino acids with free diet intake for growth and development.

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.

Ethical Analysis and Policy Recommendations Regarding Domino Liver Transplantation

Due to the widening gap between supply and demand, patients who need a liver transplant due to metabolic disease may be asked to serve as domino liver donors-to have their native liver transplanted into another candidate. We here analyze the ethical problems surrounding informed consent for the implant and explant procedures in transplant candidates who will serve as domino donors, using the case of a child with maple syrup urine disease. We discuss the need for 2 distinct consent processes separated in time to ensure that potential domino donors (or their surrogates) give a truly voluntary consent. We propose a Domino Donor Advocate-based on the concept of the independent living donor advocate to help the patient and/or his or her surrogates consider the risks, benefits and alternatives. Finally, we evaluate the Organ Procurement and Transplantation Network policy regarding "therapeutic organ donation" and propose several modifications to ensure that the decision by the potential domino donor (and/or his or her surrogate) is voluntary and informed.

Genetic, hematological, and immunological disorders transmissible with liver transplantation

It is well recognized that solid organ transplantation can transmit bacterial infection and chronic viral hepatitis as well as certain cancers. As indications for liver transplantation (LT) have expanded, it has been used to treat and even cure certain genetic cholestatic disorders, urea cycle defects, and coagulation abnormalities; many of these conditions are potentially transmissible with LT as well. It is important for clinicians and transplant patients to be aware of these potentially transmissible conditions as unexplained post-LT complications can sometimes be related to donor transmission of disease and thus should prompt a thorough exploration of the donor allograft history. Herein, we will review the reported genetic, metabolic, hematologic, and immunological disorders that are transmissible with LT and describe clinical scenarios in which these cases have occurred, such as in inadvertent or recognized transplantation of a diseased organ, domino transplantation, and with living related liver donation. Liver Transplantation 23 663-678 2017 AASLD.

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.

Liver transplantation for pediatric inherited metabolic disorders: Considerations for indications, complications, and perioperative management

LT is an effective therapeutic option for a variety of IEM. This approach can significantly improve the quality of life of patients who suffer from severe disease manifestations and/or life-threatening metabolic decompensations despite medical/dietary management. Due to the significant risks for systemic complications from surgical stressors, careful perioperative management is vital. Even after LT, some disorders require long-term dietary restriction, medical management, and monitoring of metabolites. Successful liver transplant for these complex disorders can be achieved with disease- and patient-specific strategies using a multidisciplinary approach. In this article, we review indications, complications, perioperative management, and long-term follow-up recommendations for IEM that are treatable with LT.

Successful living donor liver transplantation for classical maple syrup urine disease

MSUD is an autosomal recessive condition characterized by a deficiency in the enzyme, BCKDH, which catalyzes the breakdown of BCAAs. If left untreated, MSUD can result in mental retardation, central nervous system disorders, and even death. Most patients with MSUD are treated with a restricted protein diet and milk from which BCAAs have been removed. LT has been shown effective in patients with MSUD. This report describes the case of a 15-month-old boy who received a liver graft from his mother. Transplantation was successful, and the patient was then able to ingest a normal diet. Despite episodes of acute rejection, chylous ascites, and high fever (40 °C), he has shown no evidence of MSUD recurrence. These findings indicate that patients with MSUD can be successfully treated by LDLT, even when the donor is a heterozygous carrier of a mutated BCKDH gene.

Living donor liver transplantation in maple syrup urine disease - Case series and world's youngest domino liver donor and recipient

MSUD occurs due to deficiency of enzyme BCKAD required for metabolism of leucine, isoleucine, and valine leading to the accumulation of these and their ketoacids causing acute metabolic decompensation manifesting as encephalopathy or sudden death. The patient requires special protein-restricted diet to survive. As this enzyme is expressed in liver, liver transplantation has been successfully performed as a cure. We report two patients of MSUD who underwent LDLT while their livers were used as a domino graft for other biliary cirrhotic patients. A 22-month-old male child diagnosed as a case of classic MSUD underwent LDLT from an altruistic aunt as donor following which his serum leucine levels normalized on an unrestricted protein diet. His liver was used as a domino graft. A 38-month-old female child with diagnosed MSUD underwent LDLT from a swap donor, and her liver was used as a domino graft. Her DQ improved post-transplant. LDLT from non-heterozygous donors is a cure for classical MSUD. Their livers can be used as domino grafts for non-MSUD cases.

Living related versus deceased donor liver transplantation for maple syrup urine disease

Maple syrup urine disease (MSUD) is an inherited disorder of branched chain ketoacid (BCKA) oxidation associated with episodic and chronic brain disease. Transplantation of liver from an unrelated deceased donor restores 9-13% whole-body BCKA oxidation capacity and stabilizes MSUD. Recent reports document encouraging short-term outcomes for MSUD patients who received a liver segment from mutation heterozygous living related donors (LRDT). To investigate effects of living related versus deceased unrelated grafts, we studied four Brazilian MSUD patients treated with LRDT who were followed for a mean 19 ± 12 postoperative months, and compared metabolic and clinical outcomes to 37 classical MSUD patients treated with deceased donor transplant. Patient and graft survival for LRDT were 100%. Three of 4 MSUD livers were successfully domino transplanted into non-MSUD subjects. Following LRDT, all subjects resumed a protein-unrestricted diet as mean plasma leucine decreased from 224 ± 306 μM to 143 ± 44 μM and allo-isoleucine decreased 91%. We observed no episodes of hyperleucinemia during 80 aggregate postoperative patient-months. Mean plasma leucine:isoleucine:valine concentration ratios were ~2:1:4 after deceased donor transplant compared to ~1:1:1.5 following LRDT, resulting in differences of predicted cerebral amino acid uptake. Mutant heterozygous liver segments effectively maintain steady-state BCAA and BCKA homeostasis on an unrestricted diet and during most catabolic states, but might have different metabolic effects than grafts from unrelated deceased donors. Neither living related nor deceased donor transplant affords complete protection from metabolic intoxication, but both strategies represent viable alternatives to nutritional management.