Real-world management of maple syrup urine disease (MSUD) metabolic decompensations with branched chain amino acid-free formulas in France and Germany: A retrospective observational study

Unlocking hope: domino liver transplantation for maple syrup syndrome, a single center experience work carried out at the King Fahad Specialist Hospital

Background

Maple Syrup Urine Disease (MSUD) is an autosomal recessive disorder caused by mutations in the BCKDH complex, leading to the accumulation of branched-chain amino acids. Severe cases of MSUD often require liver transplantation (LT) to restore metabolic stability and prevent neurological complications. Domino liver transplantation (DLT) using MSUD livers has emerged as an innovative approach to expand the donor pool, leveraging the fact that MSUD-affected livers can function normally in recipients without developing MSUD due to extrahepatic BCKDH activity.

Methods &Results

This study retrospectively reviews the experience at King Fahad Specialist Hospital in Dammam, where seven patients with MSUD underwent LT, with their explanted livers subsequently transplanted into seven other recipients. The results demonstrate the feasibility and safety of this approach, with a 100% survival rate for MSUD patients at a median follow-up of 2.9 years. For the domino recipients, the 3-year graft and patient survival rate was 71.4%, with two graft-related fatalities.

Conclusion

The study highlights the importance of careful recipient selection, optimal graft-to-recipient weight ratio, and the potential for hybrid dual graft transplantation in cases where graft volume is insufficient. The findings suggest that DLT using MSUD livers is a viable option, particularly in regions with limited deceased donor activity, and should be considered in mature liver transplant programs to address organ shortages.

Assessment of quality of life in families affected by maple syrup urine disease: a cross sectional study

OBJECTIVES

Maple syrup urine disease (MSUD) is considered one of the intoxication-type inborn errors of metabolism (IT-IEM). Patients with MSUD are afflicted with a chronic illness, and the disease and its management have both physical and psychological consequences for the patients and their families. The aim of this study was to assess the quality of life (QoL) and its main determining factors for patients with MSUD and their families under follow-up in Sohag University Hospital.

METHODS

Parents of 36 patients with MSUD participated in a questionnaire translated into Arabic to assess their QoL. Subsequently, a file review was conducted to identify any key factors that could potentially influence the parents' QoL.

RESULTS

The results of the study indicated that 27 (75 %) of the MSUD patients exhibited poor QoL, while only 9 (25 %) patients reported good QoL across all studied aspects. Significant differences were observed between the two groups in terms of the disease onset, whether acute or asymptomatic (diagnosed before acute metabolic decompensation) (p=0.001) and the type of screening employed (p=0.007).

CONCLUSIONS

There is a paucity of data on the QoL of pediatric patients with IT-IEM, including MSUD. The methodological approaches and assessment instruments utilized in existing studies are inconsistent. Identifying the factors that affect QoL would be beneficial for improving patient care, evaluating outcomes and treatments, and planning effective social and psychological interventions to enhance the patients' QoL.

Melatonin improves behavioral parameters and oxidative stress in zebrafish submitted to a leucine-induced MSUD protocol

Maple syrup urine disease (MSUD) is an inherited metabolic disorder caused by a deficiency in branched-chain alpha-ketoacid dehydrogenase complex (BCKAC). The treatment is a standard therapy based on a protein-restricted diet with low branched-chain amino acids (BCAA) content to reduce plasma levels and, consequently, the effects of accumulating their metabolites, mainly in the central nervous system. Although the benefits of dietary therapy for MSUD are undeniable, natural protein restriction may increase the risk of nutritional deficiencies, resulting in a low total antioxidant status that can predispose and contribute to oxidative stress. As MSUD is related to redox and energy imbalance, melatonin can be an important adjuvant treatment. Melatonin directly scavenges the hydroxy radical, peroxyl radical, nitrite anion, and singlet oxygen and indirectly induces antioxidant enzyme production. Therefore, this study assesses the role of melatonin treatment on oxidative stress in brain tissue and behavior parameters of zebrafish (Danio rerio) exposed to two concentrations of leucine-induced MSUD: leucine 2 mM and 5mM; and treated with 100 nM of melatonin. Oxidative stress was assessed through oxidative damage (TBARS, DCF, and sulfhydryl content) and antioxidant enzyme activity (SOD and CAT). Melatonin treatment improved redox imbalance with reduced TBARS levels, increased SOD activity, and normalized CAT activity to baseline. Behavior was analyzed with novel object recognition test. Animals exposed to leucine improved object recognition due to melatonin treatment. With the above, we can suggest that melatonin supplementation can protect neurologic oxidative stress, protecting leucine-induced behavior alterations such as memory impairment.

Maple syrup urine disease due to a paracentric inversion of chr 19 that disrupts BCKDHA: A case report

Maple syrup urine disease (MSUD) is a rare autosomal recessive inherited disorder of branched-chain amino acid metabolism caused by mutations in BCKDHA, BCKDHB, and DBT that encode the E1α, E1β, and E2 subunits of the branched-chain α-ketoacid dehydrogenase (BCKD) complex. Various MSUD-causing variants have been described; however, no structural rearrangements in BCKDHA have been reported to cause the classic MSUD phenotype. Here, we describe the classic patient with MSUD with compound heterozygous pathogenic variants in BCKDHA: a missense variant (NM_000709.3:c.757G > A, NP_000700.1:p.Ala253Thr) and a paracentric inversion disrupting Intron 1 of BCKDHA, which was identified by whole-genome sequencing and validated by fluorescence in situ hybridization. Using the sequence information of the breakpoint junction, we gained mechanistic insight into the development of this structural rearrangement. Furthermore, the establishment of junction-specific polymerase chain reaction could facilitate identification of the variant in case carrier or future prenatal/preimplantation tests are necessary.

Maple syrup urine disease decompensation misdiagnosed as a psychotic event

Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disease resulting in impaired or absent breakdown of branched-chain amino acids (BCAA) valine, isoleucine, and leucine. Classic MSUD often presents in post-natal periods, at times before newborn screening results, and is treated with a protein restricted diet supplemented with medical food and close follow up to prevent toxic buildup of blood leucine.

Acute episodes of decompensation are prevented by early recognition and treatment. Acute episodes of metabolic decompensation in patients with MSUD are medical emergencies that require immediate treatments as cerebral edema may lead to brain-stem compression resulting in death. As the early outcomes improve for MSUD patients, the long-term sequelae of chronic hyperleucemia are being elucidated and include cognitive impairment, mental health disorders, and movement disorders.

In this report we present an adult patient with MSUD with attention deficit, hyperactivity type (ADHD) and depression due to prolonged exposure to elevated leucine managed with community support services who presented to the emergency department with new onset of acute hallucinations. He was held in the emergency department awaiting involuntary commitment to a psychiatric facility and underwent psychiatric treatments for suspected new onset hallucinations without improvement. Upon notification of metabolic specialists and initiation of appropriate therapy of MSUD, his leucine level normalized rapidly with resolution of his acute psychosis.

This case describes the acute presentation of psychosis in the setting of long-term toxicity of leucine. This case also highlights the importance of transition of care, education and planning in patients with inborn errors of metabolism.

Intravenous administration of a branched-chain amino-acid-free solution in children and adults with acute decompensation of maple syrup urine disease: a prospective multicentre observational study

Background

Patients with maple syrup urine disease (MSUD) experiencing metabolic decompensations have traditionally been treated with branched-chain amino acid (BCAA)-free mixture via oral or nasogastric administration routes. In some patients, enteral administration is not possible, either because the patient presents with vomiting, coma, or refuses nasogastric administration, thus intravenous (IV) BCAA-free solution is an appropriate intervention for these challenging cases.

Aims

This study aimed to evaluate the effectiveness and safety of managing metabolic decompensations by administering an IV BCAA-free solution.

Methods

This is an observational prospective study of data from MSUD patients hospitalised for decompensation episodes between 2010 and 2016 at 6 centres for rare metabolic diseases in France.

Results

A total of 24 patients (16 males; 8 females) experiencing 126 MSUD metabolic decompensation episodes (39 in children; 87 in adults) were admitted to hospital. At presentation, mean leucine plasma concentration was ≥ 381 µmol/L in 113/126 (89.7%) episodes. Children were treated with continuous IV BCAA-free solution at doses of 0.8 to 2.0 g/kg/day, for 4.8 days and adults for 3.8 days at doses of 0.5 to 2.6 g/kg/day. In the efficacy set of 102 analysable episodes leucine concentrations were normalised (to below 381 µmol/L) in 82% (n = 18/22) of episodes in children and in 84% (n = 67/80) of episodes in adults. Mean time to leucine normalisation was 3.0 days. This was significantly (p < 0.001) shorter than the algorithmically predicted time to leucine normalisation with traditional BCAA-free mixture. Duration of hospitalisation was significantly longer for children than for adults (7.1 days in children vs 5.2 days in adults, p = 0.012). No treatment-related adverse events were reported in any patients on IV BCAA-free solution.

Conclusion

The IV BCAA-free solution is safe and effective in normalising leucine concentrations during MSUD decompensation episodes in both children and adults, offering a practical treatment alternative for those patients who cannot receive BCAA-free mixture via oral or nasogastric routes.

Intravenous branched-chain amino-acid-free solution for the treatment of metabolic decompensation episodes in Spanish pediatric patients with maple syrup urine disease

BACKGROUND

Metabolic decompensation episodes (DEs) in Maple Syrup urine disease (MSUD) result in brain accumulation of toxic branched-chain amino acids (BCAAs) and their respective branched-chain α-keto acids that could induce neuroinflammation, disturb brain bioenergetics, and alter glutamate and glutamine synthesis. These episodes require immediate intervention to prevent irreversible neurological damage. Intravenous (IV) administration of BCAA-free solution could represent a powerful alternative for emergency treatment of decompensations.

METHODS

This pediatric series discusses the management of DEs in MSUD patients with IV BCAA-free solution, as an emergency treatment for DEs or as a prophylactic in cases requiring surgery. Clinical evolution, amino acid profile and adverse effects were evaluated.

RESULTS

We evaluated the use of BCAA-free solution in 5 DEs in 5 MSUD pediatric patients, all with significantly elevated plasma leucine levels at admission (699-3296 μmol/L) and in 1 episode of risk of DE due to surgery. Leucine normalization was achieved in all cases with resolution or improvement of clinical symptoms following IV BCAA-free solution. The duration of administration ranged from 3-20 days. Administration of IV BCAA-free solution at the beginning of a DE could reverse depletion of the amino acids that compete with BCAAs for the LAT1 transporter, and the observed depletion of alanine, despite IV alanine supplementation. No related adverse events were observed.

CONCLUSIONS

Administration of standardized IV BCAA-free solution in emergency settings constitutes an important and safe alternative for the treatment of DEs in MSUD, especially in pediatric patients for whom oral or enteral treatment is not viable.