Long-Term Amino Acid Homeostasis, Neurodevelopmental and Growth Profiles Following Liver Transplantation in Maple Syrup Urine Disease.

INTRODUCTION: Maple syrup urine disease (MSUD) is caused by the deficiency of branched-chain keto acid dehydrogenase (BCKAD) and, it is well described that BCKAD contributed by an allograft following liver transplantation (LT) phenotypically normalizes this inborn error of metabolism (IEM). There is, however, a paucity of data especially with regards to the neurodevelopmental aspects and catch-up growth profiles after LT in a resource-challenged setting. We present our series of children under 6 years of age who underwent LT for MSUD particularly focusing on their amino acid homeostasis, neurodevelopmental and somatic growth profiles. METHODS: Of 580 consecutive pediatric LT (PLT) performed between January 2011 and December 2022, all children who underwent LT for MSUD were included for analysis. Data accrued included peri-LT details, pre- and post-LT metabolic profile, neurodevelopmental assessment, somatic growth evaluation, and long-term outcomes. RESULTS: Six children underwent LT for MSUD with a median age and weight at LT of 20.5 (IQR: 8-60) months and 10.1 (IQR: 6.7-15.8) kg, respectively. One explanted liver was used as a domino graft for Arginase deficiency. Median follow-up period was 52.5 (IQR: 27-94) months. None had vascular or biliary complications. Following LT, all children were started on an unrestricted protein diet and had normalization of BCAA levels. Post-LT height and weight improved by 1 SD but did not achieve the normal profile. None of the children had neuro-deterioration and have achieved new milestones. CONCLUSION: This is the first-report presenting the growth aspects, amino acid and neurodevelopmental profiles of children who underwent LT for MSUD within the socio-economic-cultural idiosyncrasies and constraints prevalent in our part of the world.

Seizure Characteristics and EEG Features in Intoxication Type and Energy Deficiency Neurometabolic Disorders in the Pediatric Intensive Care Unit: Single-Center Experience Over 10 Years.

BACKGROUND: Acute metabolic crises in inborn errors of metabolism (such as urea cycle disorders, organic acidemia, maple syrup urine disease, and mitochondrial disorders) are neurological emergencies requiring management in the pediatric intensive care unit (PICU). There is a paucity of data pertaining to electroencephalograms (EEG) characteristics in this cohort. We hypothesized that the incidence of background abnormalities and seizures in this cohort would be high. Neuromonitoring data from our center's PICU over 10 years are presented in this article. METHODS: Data were collected by retrospective chart review for patients with the aforementioned disorders who were admitted to the PICU at our institution because of metabolic/neurologic symptoms from 2008 to 2018. Descriptive statistics (χ2 test or Fisher's exact test) were used to study the association between EEG parameters and outcomes. RESULTS: Our cohort included 40 unique patients (8 with urea cycle disorder, 7 with organic acidemia, 3 with maple syrup urine disease, and 22 with mitochondrial disease) with 153 admissions. Presenting symptoms included altered mentation (36%), seizures (41%), focal weakness (5%), and emesis (28%). Continuous EEG was ordered in 34% (n = 52) of admissions. Twenty-three admissions were complicated by seizures, including eight manifesting as status epilepticus (seven nonconvulsive and one convulsive). Asymmetry and focal slowing on EEG were associated with seizures. Moderate background slowing or worse was noted in 75% of EEGs. Among those patients monitored on EEG, 4 (8%) died, 3 (6%) experienced a worsening of their Pediatric Cerebral Performance Category (PCPC) score as compared to admission, and 44 (86%) had no change (or improvement) in their PCPC score during admission. CONCLUSIONS: This study shows a high incidence of clinical and subclinical seizures during metabolic crisis in patients with inborn errors of metabolism. EEG background features were associated with risk of seizures as well as discharge outcomes. This is the largest study to date to investigate EEG features and risk of seizures in patients with neurometabolic disorders admitted to the PICU. These data may be used to inform neuromonitoring protocols to improve mortality and morbidity in inborn errors of metabolism.

Genotypic and Phenotypic Spectrum of maple syrup urine disease in Zhejiang of China.

BACKGROUND: Maple Syrup Urine Disease (MSUD) is an autosomal recessive metabolic disorder originating from defects in the branched-chain α-ketoacid dehydrogenase (BCKDH) complex encoded by BCKDHA, BCKDHB, and DBT. This condition presents a spectrum of symptoms and potentially fatal outcomes. Although numerous mutations in the BCKDH complex genes associated with MSUD have been identified, the relationship between specific genotypes remains to be fully elucidated. AIM: Our objective was to predict the pathogenicity of these genetic mutations and establish potential links between genotypic alterations and the clinical phenotypes of MSUD. DESIGN: Retrospective population-based cohort. METHODS: We analyzed 20 MSUD patients from the Children's Hospital at Zhejiang University School of Medicine (Hangzhou, China), recorded from January 2010 to May 2023. Patients' blood samples were collected by heel-stick through neonatal screening, and amino acid profiles were measured by tandem mass spectrometry. In silico methods were employed to assess the pathogenicity, stability, and biophysical properties. Various computation tools were utilized for assessment, namely PredictSNP, MAGPIE, iStable, Align GVGD, ConSurf and SNP effect. RESULTS: We detected 25 distinct mutations, including 12 novel mutations. The BCKDHB gene was the most commonly affected (53.3%) compared to the BCKDHA gene (20.0%) and DBT gene (26.7%). In silico webservers predicted all novel mutations were disease-causing. CONCLUSIONS: This study highlights the genetic complexity of MSUD and underscores the importance of early detection and intervention. Integrating neonatal screening with advanced sequencing methodologies is pivotal in ensuring precise diagnosis and effective management of MSUD, thereby significantly improving the prognosis for individuals afflicted with this condition.

Inborn errors of metabolism and pregnancy.

As the diagnosis and treatment of patients with inborn errors of metabolism has improved dramatically over the years, more people with these conditions are surviving into child-bearing years. Given the changes in metabolism throughout pregnancy, this time presents a unique challenge in their care. Overall metabolic shifts in pregnancy go from anabolism to catabolism driven by endocrinologic changes, along with changes in rates of gluconeogenesis, glucose consumption, amino acid transport, protein consumption, and lipid breakdown, result in a complicated metabolic picture. Additionally, maternal inborn errors of metabolism can affect a fetus, as in phenylketonuria, and fetal inborn errors of metabolism can affect the mother, as in certain fatty acid oxidation disorders. Data on these conditions is often very limited. A summary of the current literature, risks associated with pregnancy in inborn errors of metabolism, and suggestions for management of these conditions will be presented.

Exploratory Untargeted Metabolomics of Dried Blood Spot Samples from Newborns with Maple Syrup Urine Disease.

Currently, tandem mass spectrometry-based newborn screening (NBS), which examines targeted biomarkers, is the first approach used for the early detection of maple syrup urine disease (MSUD) in newborns, followed by confirmatory genetic mutation tests. However, these diagnostic approaches have limitations, demanding the development of additional tools for the diagnosis/screening of MUSD. Recently, untargeted metabolomics has been used to explore metabolic profiling and discover the potential biomarkers/pathways of inherited metabolic diseases. Thus, we aimed to discover a distinctive metabolic profile and biomarkers/pathways for MSUD newborns using untargeted metabolomics. Herein, untargeted metabolomics was used to analyze dried blood spot (DBS) samples from 22 MSUD and 22 healthy control newborns. Our data identified 210 altered endogenous metabolites in MSUD newborns and new potential MSUD biomarkers, particularly L-alloisoleucine, methionine, and lysoPI. In addition, the most impacted pathways in MSUD newborns were the ascorbate and aldarate pathways and pentose and glucuronate interconversions, suggesting that oxidative and detoxification events may occur in early life. Our approach leads to the identification of new potential biomarkers/pathways that could be used for the early diagnosis/screening of MSUD newborns but require further validation studies. Our untargeted metabolomics findings have undoubtedly added new insights to our understanding of the pathogenicity of MSUD, which helps us select the appropriate early treatments for better health outcomes.

Computational structural genomics and clinical evidence suggest BCKDK gain-of-function may cause a potentially asymptomatic maple syrup urine disease phenotype.

Maple syrup urine disease (MSUD) is a disorder of branched-chain amino acid metabolism caused by a defect in the branched-chain α-ketoacid dehydrogenase (BCKD) complex (OMIM #248600). The hallmark presentation is encephalopathic crisis in neonates, but can also present with metabolic decompensation, developmental delays, and feeding difficulties. Biochemical evidence for MSUD includes elevated branched-chain amino acids (BCAA) and the pathognomonic presence of alloisoleucine. The BCKD complex contains several subunits associated with autosomal recessive MSUD, while its regulatory proteins have less well-defined disease associations. We report on two families with the same BCKDK variant (c.1115C>G (p.Thr372Arg)). Probands were detected on newborn screening and demonstrated biochemical evidence of MSUD. The variant was identified in reportedly asymptomatic parents and additional family members who had elevated BCAA and alloisoleucine, following an autosomal dominant pattern of inheritance. To better define the functional effect of the variant on the kinase, we completed molecular modeling using sequence-based (2D), structural-based (3D), and dynamic-based (4D) analyses. The BCKDK variant modeling indicated a gain-of-function which leads to impaired BCAA catabolism consistent with the biochemical evidence in this cohort. Combining the evidence gained from molecular modeling with the absence of metabolic decompensation in our patients and several adult family members, despite encountering stressors typically problematic in classic MSUD, we suggest that heterozygous gain-of-function variants in BCKDK may represent a novel biochemical phenotype of MSUD with a benign clinical course.

Identifying Metabolic Diseases That Precipitate Neonatal Seizures.

Although a rare cause of neonatal seizures, inborn errors of metabolism (IEMs) remain an essential component of a comprehensive differential diagnosis for poorly controlled neonatal epilepsy. Diagnosing neonatal-onset metabolic conditions proves a difficult task for clinicians; however, routine state newborn screening panels now include many IEMs. Three in particular-pyridoxine-dependent epilepsy, maple syrup urine disease, and Zellweger spectrum disorders-are highly associated with neonatal epilepsy and neurocognitive injury yet are often misdiagnosed. As research surrounding biomarkers for these conditions is emerging and gene sequencing technologies are advancing, clinicians are beginning to better establish early identification strategies for these diseases. In this literature review, the authors aim to present clinicians with an innovative clinical guide highlighting IEMs associated with neonatal-onset seizures, with the goal of promoting quality care and safety.

The interplay of psychosis and non-compliance with fatal outcome in an adult with MSUD.

Significant progress has been achieved in enhancing early outcomes for individuals with maple syrup urine disease (MSUD), a rare metabolic disorder that leads to the accumulation of branched-chain amino acids leucine, isoleucine, and valine, where leucine is known as the primary neurotoxic metabolite. Newborn screening is helpful in early diagnosis and implementation of dietary treatment, thus reducing neurological deterioration and complications in young children. However, patients face the life-long challenge of maintaining metabolic control through adherence to a strict low-leucine diet to avoid long-term consequences of chronic hyperleucinemia, which include cognitive deficits, mood disorders, and movement disorders. This case report exemplifies the complex involvement of MSUD in adult survivors. Despite presenting early in life, the patient thrived until the onset of psychiatric symptoms. The subject of this case is a 25-year-old woman with MSUD, who remained in her usual state of health until presentation to the emergency department (ED) with psychosis and altered mental status. However, due to a lack of medical records and poor communication, there was a delay in considering MSUD as a primary cause of her psychiatric symptoms. Although a genetics consultation was later arranged and efforts were made to decrease plasma leucine to the therapeutic range, these interventions proved inadequate in halting her deterioration in health. Her condition worsened within 72 h, culminating in her untimely death. This case emphasizes the comorbidity of psychiatric involvement in MSUD, which contributes to metabolic decompensation that can lead to cerebral edema and death. This case also highlights the pressing need for enhanced strategies for the acute management and long-term care of MSUD patients with psychiatric involvement, particularly in scenarios where mental disturbance could lead to noncompliance.

Changes in branched-chain amino acids in an infant with maple syrup urine disease during perioperative pediatric liver transplant: A case report.

An 11-month-old female infant diagnosed with classic subtype IB maple syrup urine disease underwent living donor liver transplantation. Blood samples for plasma amino acid analysis were collected during the three phases of the operation. Despite the perioperative prophylactic administration of 12.5% hypertonic dextrose solution with insulin and a 20% intralipid emulsion, the blood levels of the branched-chain amino acids increased dramatically during surgery, consistent with an acute intraoperative metabolic decompensation. However, these blood levels normalized soon after liver transplantation with an excellent outcome. We suggest that the occurrence of an intraoperative metabolic crisis during liver transplantation is not necessarily a sign of graft failure.

Functional decompensation after administration of compound diphenoxylate in a maple syrup urine disease patient:case report and literature review / 中华全科医师杂志

A 14-year girl was admitted with akinesia and difficulty walking due to gait instability after two oral doses of compound diphenoxylate (lomotil). When she was 18-month old, drowsiness and inability to walk were observed after taking lomotil, the symptoms were relieved by taking B vitamins for treatment. The laboratory tests showed the increased blood branched chain amino acid levels; gene detection indicated that the child had compound heterozygous variations of c.745G>A(p.G249S) and c.485-1G>C in the BCKDHA gene. The girl was finally diagnosed as maple syrup urine disease. The domestic and foreign literature was searched, and 11 child cases of maple syrup urine disease with onset of unsteadiness and ataxia were reported, none of whom was associated with oral administration of compound diphenoxylate.

Necrosis en espejo de ganglios basales en la enfermedad de la orina con olor a jarabe de arce. Presentación de un caso / Mirror necrosis of basal ganglia in maple syrup urine disease. A case report

RESUMEN La enfermedad de la orina con olor a jarabe de arce es una enfermedad genética autosómica recesiva, cerebral degenerativa. Es causada por un déficit en la actividad de la deshidrogenasa de los cetoácidos de cadena ramificada, que provoca inadecuado almacenamiento de los tres aminoácidos esenciales de dicha cadena. Esto genera una neurotoxicidad severa que puede llevar a la muerte. Se manifiesta clínicamente por deterioro neurológico, retraso psicomotor, problemas de alimentación, orina con olor característico. Sus consecuencias cerebrales pueden ser definidas mediante tomografía axial computarizada. Este artículo tiene como objetivo presentar un caso de enfermedad de la orina con olor a jarabe de arce con hipodensidad bilateral de los ganglios basales por necrosis en espejo, detectado mediante estudio tomográfico. Se trata de una paciente femenina, de 9 años de edad con cuadro anterior de cetoacidosis no diabética. Posterior a la realización de apendicectomía, comenzó con cuadro comatoso que requirió estudio tomográfico mediante el cual se constató edema cerebral. Evolucionó tórpidamente, por lo que requirió nuevo estudio tomográfico que demostró empeoramiento de las condiciones neurológicas al reflejarse en la imagen hipodensidad bilateral a nivel de los núcleos basales por necrosis. La enfermedad de la orina con olor a jarabe de arce es una afección rara, con diversas formas clínicas. Requiere de estudios de laboratorio que la confirmen e imágenes como tomografía computarizada que, como en este caso, ayuden a evidenciar el daño neurológico. Fue muy característica la hipodensidad de ganglios basales asociada a edema cerebral.

ABSTRACT Maple syrup urine disease is an autosomal recessive genetic degenerative brain disease. It is caused by a deficit in branched-chain ketoacid dehydrogenase activity, which causes inadequate storage of the three essential amino acids of said chain. This generates severe neurotoxicity that can lead to death. It is clinically manifested by neurological deterioration, psychomotor retardation, feeding problems, urine with a characteristic odor. Its cerebral consequences can be defined by computerized axial tomography. This article aims to present a case of maple syrup urine disease with bilateral hypodensity of the basal ganglia due to mirror necrosis, detected by tomographic study. This is a 9-years-old female patient with a history of non-diabetic ketoacidosis. After the appendectomy, she began with a coma that required a tomographic study, which revealed cerebral edema. She evolved torpidly, requiring a new tomographic study that showed worsening of the neurological conditions as bilateral hypodensity at the level of the basal nuclei due to necrosis was reflected in the image. Maple syrup urine disease is a rare condition with various clinical forms. It requires laboratory studies to confirm it and images such as computed tomography that, as in this case, help to show the neurological damage. The hypodensity of the basal ganglia associated with cerebral edema was very characteristic.

Heterozygous living donor liver transplantation for pediatric maple syrup urine disease with new compound mutation of BCKDHB gene: a case report and literature review / 器官移植

Objective To evaluate the clinical efficacy of heterozygous living donor liver transplantation for pediatric maple syrup urine disease. Methods A 3-year-old boy was admitted to the hospital on July 5, 2017 due to maple syrup urine disease for half a year. The child presented with paroxysmal dysarthria and motor dysfunction of the lower limbs under fasting status for half a year, accompanied with obvious maple syrup urine odor and slow language development. No other growth abnormality or mental defects were observed. Serum branched chain amino acid (BCAA) assay detected that the level of leucine was 684 μmol/L and 559 μmol/L for the valine. The child was diagnosed with maple syrup urine disease type b based on gene detection combined with BCAA assay. Living donor liver transplantation from his biological father was performed. Postoperatively, routine immunosuppression, anti-virus, anti-infection therapies, maintenance of fluid, electrolyte, and acid-base balance and other necessary nutritional support were given. The dose of tacrolimus was adjusted according to biochemical parameters and cytochrome P450(CYP)3A5 genotype of the recipient. Glucocorticoid administration was terminated at approximately 6 months after operation. Results The liver function of the recipient was recovered to normal range at postoperative 1 month, and basically stabilized at 3 years after surgery. The amino acid level was decreased to normal level immediately after operation, and BCAA was continually declined after normal diet for postoperative 1 month. As of the submission date, the recipient grew well in a stable condition and achieved high quality of life. Conclusions Heterozygous living donor liver transplantation is a safe and effective treatment of maple syrup urine disease, which reduces the possibility of sudden acute metabolic events, significantly improves the quality of life of the recipient and provides a novel idea for surgical treatment of maple syrup urine disease.

Clinical utility of low branched-chain amino acid modular diets in patients with isovaleric aciduria and maple syrup urine disease

@#Introduction: Modular diets (MDs) with low amount of offending amino acids have been developed using locally available food ingredients as alternatives to commercial formulas for the treatment of branched-chain organic acidurias (BCOAs). Herein, we conducted a clinical investigation of MDs in patients with BCOAs. Methods: Modular diet A (MDA), with low leucine was produced for maple syrup urine disease (MSUD), and modular diet B (MDB) products, MDB-1, -2, -3, and -4, with low leucine, valine, methionine and threonine were made for isovaleric aciduria (IVA)/methylmalonic aciduria (MMA)/propionic aciduria (PA). Children aged 4-18 years, with MSUD, IVA, PA or MMA were invited to participate in the study. The research subjects switched from metabolic formula protocol to modular diet protocol. They were followed-up at 0, 1, 2, 4, and 6 months. Clinical efficacies of MDs were determined by completion of study, compliance to MDs, clinical outcomes and complications, and parental satisfaction. Results: Six children (2 MSUD and 4 IVA) participated and completed the study. Compliance to MDA was 100% in MSUD subjects with G-tube feeding, while compliance to MDB varied among self-fed individuals with IVA. One subject with MSUD was clinically stable throughout the study, while the other experienced metabolic instability. All IVA individuals showed clinical and laboratory stability during the study. One MSUD and three IVA families preferred the metabolic formula, whereas the other IVA family reported no preference and the other MSUD subject preferred MDs. Conclusion: We provided a proof of concept in developing modular diets for BCOAs, and showed favourable outcomes when using MDs in IVA and varying clinical benefits in MSUD.

Quantitative Determination of Branched-Chain Amino Acids in Dried Blood Spot Samples by LC-MSMS and its Application in Diagnosis and Follow-Up of Chilean Patients with Maple Syrup Urine Disease

Abstract Elevation of branched-chain amino acids (BCAAs) in biological fluids indicates a deficiency in the branched-chain ketoacid dehydrogenase complex, which causes maple syrup urine disease (MSUD). Detection of increased levels of alloisoleucine confirms the diagnosis, while routine monitoring of leucine concentration is crucial for preventing metabolic decompensation and neurological dysfunction. In the metabolic center at Universidad de Chile, we have confirmed and monitored more than fifty MSUD patients in the last 20 years. Most diagnoses were made by clinical and sibling diagnosis, as MSUD is not included in the Chilean national newborn screening program. Shortening diagnosis time has a fundamental impact on the outcome of patients, therefore we focused on implementing detection of BCAAs in dried blood spot by liquid chromatography mass spectrometry (LC-MSMS) for disease confirmation as well as for biochemical monitoring. Retrospective analysis of samples from 9 diagnosed MSUD patients were performed; BCAAs values were determined via MSMS and LC-MSMS conducted in parallel. Leucine and alloisoleucine levels were positively correlated with patient's diagnosis age. Alloisoleucine was significatively elevated as early as 24 hr after birth. A predictable variation in BCAAs levels after nutritional intervention among diagnosed MSUD patients was found.

Diálisis peritoneal en un neonato con enfermedad de la orina con olor a jarabe de arce. A propósito de un caso / Peritoneal dialysis in a neonate with maple syrup urine disease. A case report

La enfermedad de jarabe de arce es una entidad autosómica recesiva producida por un error congénito en el metabolismo de tres aminoácidos esenciales de cadena ramificada: valina, leucina e isoleucina. La forma neonatal de esta enfermedad se manifiesta por un cuadro de compromiso neurológico grave y progresivo, asociado a un olor peculiar de la orina, consecuencia de la eliminación del exceso de estos aminoácidos. Este olor a azúcar quemada remeda a la melaza obtenida de los arces, lo que da nombre a esta enfermedad. El mejor método para eliminar estos tóxicos es la hemodiafiltración, pero, en los centros en los que esta práctica no es posible, la diálisis peritoneal constituye una alternativa.Se presenta a un recién nacido con leucinosis, con compromiso grave del sistema nervioso central, en quien la diálisis peritoneal fue de utilidad para superar la descompensación metabólica.

Maple syrup disease is an autosomal recessive entity caused by a congenital error in the metabolism of three essential branched-chain amino acids: valine, leucine and isoleucine. The neonatal form of this disease is expressed by a severe and progressive neurological compromise, associated with a peculiar smell of urine, a consequence of the elimination of the excess of these amino acids. This smell of burnt sugar mimics the molasses obtained from maples, which gives its name to this disease. The best method to eliminate these toxins is hemodiafiltration, but in centers where this practice is not possible, peritoneal dialysis is an alternative.We present a newborn with leukinosis with severe central nervous system involvement in whom peritoneal dialysis was useful to overcome metabolic decompensation.

Enfermedad de orina con olor a jarabe de arce: reporte de dos casos / Maple urine disease: two case reports

Introducción: La enfermedad de orina con olor a jarabe de arce (EOJA) es un trastorno del metabolismo de los aminoácidos de cadena ramificada (ACR). Tiene una incidencia de 1 en 85.000­185.000 recién nacidos (RN) vivos, siendo mayor en poblaciones con alta tasa de consanguineidad. Se debe al déficit del complejo enzimático BCKDC (Branched-chain alpha-keto acid dehydrogenase complex). Objetivo: Sensibilizar respecto al diagnóstico precoz, describiendo la presentación y evolución clínica de 2 casos presentados en menos de un año. Presentación del caso: Caso 1: Recién nacido de término (RNT), sin antecedentes mórbidos personales ni familiares, consulta al 11er día de vida (DDV) por cuadro de irritabilidad, rechazo alimentario, mirada fija e hipertonía. Hospitalizado por 55 días con progresiva mejoría neurológica. Al alta solo leve retraso del desarrollo psicomotor (RDSM). Caso 2: RNT, sin antecedentes mórbidos personales ni familiares, consultó al 12° DDV por cuadro de hipoactividad y rechazo alimentario. Hospitalizado por 70 días con evolución clínica y neurológica dificultosa. Al alta con trastorno deglutorio que requirió gastrostomía. En ambos casos se planteó sospecha de EOJA por aminoacidemia y aminoaciduria característica, confirmándose por medición cuantitativa de aminoácidos. Discusión: Existen cinco fenotipos diferentes, clasificados principalmente por presentación clínica y edad de debut, siendo el más frecuente la forma clásica (ambos casos). Resulta muy importante el diagnóstico precoz y manejo por su relación con el pronóstico neurológico, sin embargo, en Chile no se cuenta actualmente con un screening neonatal universal. El tratamiento se basa en un manejo nutricional estricto y la corrección de desequilibrios metabólicos e hidroelectrolíticos, ambos frecuentes en esta condición.

Introduction: The maple syrup urine disease (MSUD) is a metabolic disorder of branchedchain amino acids. It has an incidence of 1/85000 ­ 185000 live newborns being higher in in populations with a high rate of consanguinity. It is due to deficit BKDC enzyme complex (Branched-chain alpha-keto acid dehydrogenase complex). Objective: To raise awareness to early diagnosis, describing the presentation and clinical course of 2 cases presented in less than one year. Case report: Case 1: Full-term newborn with no personal or family history of morbidity presented the 11th day of life with irritability, food rejection, fixed stare and hypertonia. He was hospitalized for 55 days with progressive neurological improvement. At discharge only slightly delayed psychomotor development. Case 2: Full-term newborn with no personal or family history of morbidity presented the 12th day of life with hipoactivity and food rejection. He was hospitalized for 70 days with difficult clinical and neurological outcome. The patient was discharged with swallowing disorder that required gastrostomy. In both cases MSUP suspicion arises by aminoacidemia and aminoaciduria and confirmed by quantitative measurement of amino acids. Discussion: There are 5 different phenotypes classified chiefly by clinical presentation and age, being most frequent the classical form. It is very important to do an early diagnosis and management for its impact on neurological outcome; however, Chile does not currently has an universal neonatal screening. The treatment is based on a strict nutritional management and correction of metabolic and electrolyte imbalances, both common in this condition.

Brain MRI and clinical characteristics of maple syrup urine disease / 实用放射学杂志

Objective To investigate the characteristics of brain MRI in the patients with maple syrup urine disease(MSUD). Methods Nine patients with MSUD were diagnosed by gas chromatography mass spectrometry,tandem mass spectrometry and gene test.The MRI,clinical featuresand laboratory tests were analyzed.Results The 9 patients onset age were 3 days to 6 years old.The symptoms were varied such as poor response,lethargy,seizures and learning difficulties.Remarkable elevations of blood levels of leucine and valine were found in all patients.All patients had MRI examination,2 of them also took the examination of proton magnetic resonance spectroscopy (1 H-MRS).Involving cerebellar hemisphere,cerebellar peduncle,cerebral peduncle,brain stem,globus pallidus in 5 cases respectively,thalamus and posterior limb of internal capsule in 4 cases,centrum semiovale in 3 cases.2 cases also showed abnormal signal in corpus callosum,occipital,deep temporal lobe,and frontal lobe,parietal lobe.All lesions showed mild low signal intensity in T1 ,mild high signal intensity in T2 and obvious high signal intensity in DWI,except one case.1 H-MRS did not show a methyl resonance peak at 0.9 ppm in the two patients.Conclusion The MSUD lacked of specific clinical features.The MRI characteristics are the myelinated white matter such as the cerebellar hemispheres,posterior limb of the internal capsule,the brainstem,cerebellar peduncle,cerebral peduncle showing high signal in DWI.