Genotypic and phenotypic spectrum of cytosolic phosphoenolpyruvate carboxykinase deficiency.

OBJECTIVES: Pathogenic biallelic variants in PCK1 coding for the cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) cause PEPCK-C deficiency, a rare disorder of gluconeogenesis presenting with hypoglycemia, lactic acidosis, and hepatopathy. To date, there has been no systematic analysis of its phenotypic, biochemical, and genetic spectrum. METHODS: All currently published individuals and a novel patient with genetically confirmed PEPCK-C deficiency were included. Clinical, biochemical, and genetic findings were analyzed. Protein and in-silico prediction score modeling was applied to analyze potential variant effects. RESULTS: Thirty-two individuals from 25 families were found, including one previously unreported patient. The typical biochemical pattern was hypoglycemia triggered by catabolic situations, elevated urinary concentrations of tricarboxylic acid cycle metabolites, mildly elevated alanine and aspartate aminotransferase and elevated lactate concentrations in serum. Plasma glutamine concentrations were elevated in some patients and may be a suitable marker for newborn screening. With adequate treatment, biochemical abnormalities usually normalized following a hypoglycemic episode. Symptom onset usually occurred in infancy with a broad range from neonatal age to adulthood. Regardless of the genotype, different phenotypes with a broad clinical spectrum were found. To date, eight genotypes with nine different PCK1 variants were identified, of which alleles with the recurrent variant c.925G > A; p.(Gly309Arg) are predominant and appear to be endemic in the Finnish population. Protein modeling suggests altered manganese- and substrate-binding as superordinate pathomechanisms. CONCLUSIONS: Environmental factors appear to be the main determinant for the phenotype in patients with biallelic variants in PCK1. Based on the biochemical pattern, PEPCK-C deficiency is a recognizable cause of childhood hypoglycemia. It is a treatable disease and early diagnosis is important to prevent metabolic derailment and morbidity. Newborn screening can identify at least a sub-cohort of affected individuals through elevated glutamine concentrations in dry blood.

Potentials and current shortcomings in the cooperation between German centers for rare diseases and primary care physicians: results from the project TRANSLATE-NAMSE.

BACKGROUND: The TRANSLATE-NAMSE project with the strengthening of the centers for rare diseases with their affiliation to the European Reference Networks was a major step towards the implementation of the German National Plan of Action for People with Rare Diseases establishing better care structures. As primary care physicians, general practitioners and pediatricians play a central role in the diagnosis of patients with rare disease, as it is usually them referring to specialists and rare disease centers. Therefore, the interface management between primary care physicians and the centers for rare diseases is of particular importance. METHODS: In a mixed-method-approach an anonymous postal survey of 1,500 randomly selected primary care physicians in Germany was conducted with focus on (1) knowledge about a center for rare diseases and how it works, (2) in case of cooperation, satisfaction with the services provided by centers, and (3) expectations and needs they have with regard to the centers. In addition, in-depth telephone interviews were conducted with physicians who had already referred patients to a center. RESULTS: In total, 248 physicians responded to the survey, and 15 primary care physicians were interviewed. We observed a wide lack of knowledge about the existence of (45.6% confirmed to know at least one center) about how to access rare disease centers (50.4% of those who know a center confirmed knowledge) and what the center specializes in. In case of cooperation the evaluation was mostly positive. CONCLUSION: To improve medical care, the interplay between primary care physicians and rare disease centers needs to be strengthened. (1) To improve the communication, the objectives and functioning of the rare disease centers should become more visible. (2) Other projects dealing with the analysis and improvement of interface management between centers and primary care physicians, as described in the National Plan of Action for People with Rare Diseases, need to be implemented immediately. (3) If the project is evaluated positively, the structures of TRANSLATE-NAMSE should be introduced nationwide into the German health care system to ensure comprehensive, quality-assured care for people with rare diseases with special consideration of the key role of primary care physicians-also taking into account the financial expenditures of this new care model.

Cardiac phenotype in propionic acidemia - Results of an observational monocentric study.

BACKGROUND: Propionic acidemia (PA) is an organic aciduria caused by inherited deficiency of propionyl-CoA carboxylase. Left ventricular dysfunction and QT prolongation may lead to life-threatening complications. Systematic analyses of cardiac phenotypes, in particular effects of specific cardiac therapies, are scarce. METHODS: In this longitudinal observational monocentric study (data from 1989 to 2017) all PA patients treated at our center were included. Echocardiographic parameters (left ventricular end-diastolic diameter: LVEDD, left ventricular shortening fraction, mitral valve Doppler inflow pattern) and 12­lead electrocardiogram recordings (corrected QT interval: QTc) were analyzed. Symptomatic patients were dichotomized to the group "early-onset" (symptoms within 28 days of life) and "late-onset" (symptoms after 28 days). Associations between cardiac function, LVEDD, QTc and clinical parameters (age at onset, beta-blocker or Angiotensin-converting enzyme inhibitor = ACE-I therapy) were analyzed. RESULTS: 18 patients with PA were enrolled, 17 of them were symptomatic and one asymptomatic, with a median age at diagnosis of 6 days. 14/17 (82%) had early onset disease manifestation. Systolic left ventricular dysfunction (i.e. hypokinetic phenotype of cardiomyopathy) was diagnosed in 7/18 (39%) patients at a median age of 14.4 years, all had early onset. Two patients had a dilated left ventricle and systolic left ventricular dysfunction (i.e. dilated hypokinetic phenotype - dilated cardiomyopathy). Diastolic left ventricular dysfunction was found in 11/18 (61%) individuals, typically preceding systolic left ventricular dysfunction. ACE-I therapy did not improve systolic left ventricular function. Mean QTc was 445 ms (+/- 18.11 ms). Longer QTc was associated with larger LVEDD. CONCLUSIONS: Systolic left ventricular dysfunction was found in 39% of patients, reflecting high disease severity. Two thirds of all individuals showed signs of diastolic left ventricular dysfunction usually preceding systolic left ventricular dysfunction; it therefore may be considered as an indicator for early cardiac disease manifestation, possibly allowing earlier treatment modification. Unresponsiveness to routine cardiac therapy highlights the need to evaluate further strategies, such as liver transplantation.

MRI and (1)H-MRS in adenosine kinase deficiency.

INTRODUCTION: Adenosine kinase deficiency (ADK deficiency) is a recently described disorder of methionine and adenosine metabolism resulting in a neurological phenotype with developmental delay, muscular hypotonia, and epilepsy as well as variable systemic manifestations. The underlying neuropathology is poorly understood. We have investigated MRI and (1)H-MRS changes in ADK deficiency in order to better understand the in vivo neuropathologic changes of ADK deficiency. METHODS: Systematic evaluation of 21 MRIs from eight patients (age range 9 days-14.6 years, mean 3.9 years, median 2.7 years) including diffusion-weighted imaging in six and (1)H-MRS in five patients. RESULTS: Brain maturation was delayed in the neonatal period and in infancy (6/6), but ultimately complete. White matter changes occurring in five of eight patients were discrete, periventricular, and unspecific (4/5), or diffuse with sparing of optic radiation, corona radiata, and pyramidal tracts (1/5). Choline was low in white matter spectra (3/3), while there was no indication of low creatine in white matter or basal ganglia (5/5), and diffusion was variably decreased or increased. Central tegmental tract hyperintensity was a common finding (6/8), as was supratentorial atrophy (6/8). CONCLUSIONS: MRI changes in ADK deficiency consist of delayed but ultimately completed brain maturation with later onset of mostly unspecific white matter changes and potentially transient central tegmental tract hyperintensity. Immaturity on neonatal MRI is consistent with prenatal onset of disease and reduced choline with lower membrane turnover resulting in delayed myelination and deficient myelin maintenance.

Health-related quality of life in adolescents with inflammatory bowel disease depends on disease activity and psychiatric comorbidity.

Adolescent patients with inflammatory bowel disease (IBD) show an increased risk for behavioral and emotional dysfunction. Health-related quality of life (HRQoL) is influenced by medical illnesses, as well as by psychiatric disorders, but for adolescents with IBD, the extent to which HRQoL is influenced by these two factors is unclear. For 47 adolescent IBD patients, we analyzed disease activity, HRQoL and whether or not a psychiatric disorder was present. Disease activity was estimated using pediatric Ulcerative Colitis Activity Index and pediatric Crohn's Disease Activity Index. The IMPACT-III and the EQ-5D were used to measure HRQoL and QoL, respectively. In addition, patient and parent diagnostic interviews were performed. 55.3 % patients fulfilled DSM-IV criteria for one or more psychiatric disorders. In all patients, psychiatric comorbidity together with disease activity contributed to a reduction in quality of life. Adolescents with IBD are at a high risk for clinically relevant emotional or behavioral problems resulting in significantly lower HRQoL. We conclude that accessible, optimally structured psychotherapeutic and/or psychiatric help is needed in adolescent patients with IBD.

How much chicken is food? Questioning the definition of food by analyzing amino acid composition of modern convenience products.

BACKGROUND: Substantial differences exist between traditionally cooked and chemically designed ready-to-serve products and raise questions about the general principles and requirements of current food law. METHODS: Differences in amino acid patterns were analyzed in four examples of chicken preparations (boiled chicken meat, traditionally prepared broth from whole chicken, and two commercial chicken broths), and four examples of vegetable broth (traditionally prepared, two commercial products one of which was claimed a BIO-product, and the classic German bouillon cube). RESULTS: Chicken meat contained 284 mg of free amino acids in 100 ml of the boiled meat homogenate, with physiological peaks of glutamate (14.5 mg/100 ml), glutamine (8.5 mg/100 ml), anserine (88 mg/100 ml) and carnosine (55 mg/100 ml). The patterns significantly differ in industrially designed chicken soups with elevated peaks of glutamate, and missing anserine or carnosine. Similar results were obtained in vegetable broths. In the classic German bouillon cube, glutamate accounts for 96% of all free amino acids. CONCLUSIONS: The amino acid composition of modern ready-to-serve chicken soups and vegetable broths are far from being similar to any natural composition. We need to question current legal definitions of food, and consider its impact on eating habits, appetite regulation and obesity.

Moderate weight reduction in an outpatient obesity intervention program significantly reduces insulin resistance and risk factors for cardiovascular disease in severely obese adolescents.

Background. Metabolic risk factors like insulin resistance and dyslipidemia are frequently observed in severly obese children. We investigated the hypothesis that moderate weight reduction by a low-threshold intervention is already able to reduce insulin resistance and cardiovascular risk factors in severely obese children. Methods. A group of 58 severely obese children and adolescents between 8 and 17 years participating in a six-month-long outpatient program was studied before and after treatment. The program included behavioral treatment, dietary education and specific physical training. Metabolic parameters were measured in the fasting state, insulin resistance was evaluated in an oral glucose tolerance test. Results. Mean standard deviation score of the body mass index (SDS-BMI) in the study group dropped significantly from +2.5 ± 0.5 to 2.3 ± 0.6 (P < 0.0001) after participation in the program. A significant decrease was observed in HOMA (6.3 ± 4.2 versus 4.9 ± 2.4, P < 0.03, and in peak insulin levels (232.7 ± 132.4 versus 179.2 ± 73.3 µU/mL, P < 0.006). Significant reductions were also observed in mean levels of hemoglobin A(1c), total cholesterol and LDL cholesterol. Conclusions. These data demonstrate that already moderate weight reduction is able to decrease insulin resistance and dyslipidemia in severely obese children and adolescents.

Early onset epilepsy and inherited metabolic disorders: diagnosis and management.

Epileptic encephalopathies presenting in early life present a diagnostic and therapeutic challenge. These disorders present with multiple seizure types that are treatment resistant and associated with significant abnormalities on electroencephalographic studies. The underlying etiology in many cases may be related to an inborn error of metabolism. Efforts to establish the specific diagnosis of a genetic defect or an inborn error of metabolism often results in requests for a vast array of biochemical and molecular tests leading to an expensive workup. In this review, we present the clinician with information that provides a rationale for a selective and nuanced approach to biochemical assays, and initial treatment strategies while waiting for a specific diagnosis to be established. A careful consideration of the presentation, identification of potentially treatable conditions, and consultation with the biochemical genetics laboratory can lead to a greater measure of success while limiting cost overruns. Such a targeted approach is hoped will lead to an early diagnosis and appropriate interventions.

Clinical and biochemical features of aromatic L-amino acid decarboxylase deficiency.

OBJECTIVE: To describe the current treatment; clinical, biochemical, and molecular findings; and clinical follow-up of patients with aromatic l-amino acid decarboxylase (AADC) deficiency. METHOD: Clinical and biochemical data of 78 patients with AADC deficiency were tabulated in a database of pediatric neurotransmitter disorders (JAKE). A total of 46 patients have been previously reported; 32 patients are described for the first time. RESULTS: In 96% of AADC-deficient patients, symptoms (hypotonia 95%, oculogyric crises 86%, and developmental retardation 63%) became clinically evident during infancy or childhood. Laboratory diagnosis is based on typical CSF markers (low homovanillic acid, 5-hydroxyindoleacidic acid, and 3-methoxy-4-hydroxyphenolglycole, and elevated 3-O-methyl-l-dopa, l-dopa, and 5-hydroxytryptophan), absent plasma AADC activity, or elevated urinary vanillactic acid. A total of 24 mutations in the DDC gene were detected in 49 patients (8 reported for the first time: p.L38P, p.Y79C, p.A110Q, p.G123R, p.I42fs, c.876G>A, p.R412W, p.I433fs) with IVS6+ 4A>T being the most common one (allele frequency 45%). CONCLUSION: Based on clinical symptoms, CSF neurotransmitters profile is highly indicative for the diagnosis of aromatic l-amino acid decarboxylase deficiency. Treatment options are limited, in many cases not beneficial, and prognosis is uncertain. Only 15 patients with a relatively mild form clearly improved on a combined therapy with pyridoxine (B6)/pyridoxal phosphate, dopamine agonists, and monoamine oxidase B inhibitors.

Inborn errors of metabolism and motor disturbances in children.

Motor disturbances are very common in paediatric neurology. Often families can be reassured that these are just variants of normal development. However, abnormal movements can also be the hallmark of severe brain dysfunction of different and complex origins. This review concentrates on motor disturbances as frequent and important symptoms of inborn errors of metabolism. A structured diagnostic approach is developed taking into account age-dependent physiological developments and pathophysiological responses of gross and fine motor functions. A series of investigations are presented with the primary aim of early diagnosis of treatable conditions. The correct recognition and differentiation of movement disorders (ataxia, rigid akinetic syndrome (Fparkinsonism_), dystonia, athetosis, tremor,and others), spasticity, and neuromuscular disorders, requires profound neurological expertise. A high level of suspicion and close interaction between paediatric neurologists and specialists in inborn errors of metabolism are indispensable to effectively and timely identify patients in whom motor disturbances are the presenting and/or main symptom of an inborn error.

Mental retardation and inborn errors of metabolism.

In countries where clinical phenylketonuria is detected by newborn screening inborn errors of metabolism are rare causes of isolated mental retardation. There is no international agreement about what type of metabolic tests must be applied in patients with unspecific mental retardation. However, and although infrequent, there are a number of inborn errors of metabolism that can present in this way. Because of the high recurrence risk and the possibility of specific therapies, guidelines need to be developed and adapted to different populations. The application of a universal protocol may result in a low diagnostic performance in individual ethnic populations. Consideration of associated signs (extraneurological manifestations, psychiatric signs, autistic traits, cerebellar dysfunction, epilepsy or dysmorphic traits) greatly improves the diagnostic fulfilment.

Epilepsy and inborn errors of metabolism in children.

Epilepsy is a frequent symptom in inborn errors of metabolism, with virtually no specific seizure types or EEG signatures. It is most important to look quickly for those few inborn errors of metabolism in which specific therapies such as supplementation of cofactors or diets can make all the difference. If these investigations remain negative, epilepsy has to be treated with conventional antiepileptic drugs. Still, epilepsy is a potentially treatable symptom of many inborn errors of metabolism, and optimal treatment is of great importance for patients and their families.

Coenzyme Q(10) is decreased in fibroblasts of patients with methylmalonic aciduria but not in mevalonic aciduria.

The content of coenzyme Q(10) (CoQ(10)) was examined in skin fibroblasts of 10 patients with mevalonic aciduria (MVA) and of 22 patients with methylmalonic aciduria (MMA). Patients with these inborn errors of metabolism are thought to be at risk for CoQ(10) depletion either by direct inhibition of the proximal pathway of CoQ(10) synthesis (MVA) or indirectly by inhibition of mitochondrial energy metabolism (MMA). We demonstrated that CoQ(10) concentrations were not significantly different from controls in MVA patients, suggesting that there may be upregulatory effects. On the other hand the CoQ(10) content in fibroblasts of patients with MMA was significantly reduced.

Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up.

BACKGROUND: Aromatic L-amino acid decarboxylase (AADC) deficiency is a disorder of biogenic amine metabolism resulting in generalized combined deficiency of serotonin, dopamine and catecholamines. Main clinical features are developmental delay, muscular hypotonia, dystonia, oculogyric crises and additional extraneurological symptoms. Response to therapy has been variable and unsatisfactory; the overall prognosis is guarded. METHODS: To gain more insight into this rare disorder we collected clinical and laboratory data of nine German patients. All patients were clinically examined by one investigator, and their responses to different drug regimes were evaluated by the patients' charts. RESULTS: Symptoms were obvious from early infancy. Later, main neurological features were truncal muscular hypotonia, hypokinesia, oculogyric crises and rigor. Three patients had single seizures. All patients presented distinct extraneurological symptoms, such as hypersalivation, hyperhidrosis, nasal congestion, sleep disturbances and hypoglycaemia. In CSF all patients revealed the pattern typical of AADC with decreased concentrations of homovanillic and 5-hydroxyindoleacetic acid and elevated concentration of 3-ortho-methyldopa. Diagnosis was confirmed by measurement of AADC activity in plasma in all patients. Drug regimes consisted of vitamin B6, dopamine agonists, MAO inhibitors and anticholinergics in different combinations. No patient achieved a complete recovery from neurological symptoms, but partial improvement of mobility and mood could be achieved in some. CONCLUSION: AADC deficiency is a severe neurometabolic disorder, characterized by muscular hypotonia, dystonia, oculogyric crises and additional extraneurological symptoms. Medical treatment is challenging, but a systematic trial of the different drugs is worthwhile.

High prevalence of vitamin D deficiency in young children in a highly sunny humid country: a global health problem.

AIM: Several studies indicate a high prevalence of vitamin D deficiency among young populations. Information about the vitamin D status in young adult populations from the Middle East is scarce. The vitamin D status can be expected to be influenced by highly different factors between various countries in Europe, the Middle East and Asia. The aim of this study was to determine the prevalence of vitamin D deficiency in young Qatari children below 16 years of age. METHODS: A cross-sectional study carried out among children below 16 years of age who visited the Primary Health Care Centers (PHCs). The survey was conducted over a period from August 2007 to March 2008. Qatari nationals, male and female, aged below 16 years. A random sample of 650 children who visited the PHC Centers was approached and parents of 458 children expressed their consent to participate in this study, corresponding to a response rate of 70.5%. Face-to-face interviews were based on a questionnaire that included variables such as socio-demographic information, life style, family history and feeding patterns during infancy, and clinical information as well as laboratory investigations for biochemical assessment of vitamin D status. RESULTS: Of the total number of 458 children surveyed, 228 (49.8%) were males and 230 (50.2%) females. The prevalence of vitamin D deficiency among the studied Qatari children was (68.8%), mostly in the age group (11-16) years (61.6%). There was a significant difference between vitamin D deficient and normal children as compared to their age (P=0.013). Vitamin D deficiency was more common among girls (51.4%) than boys (48.6%). Exposure to sunlight was limited in both groups; but even lower in vitamin D deficient children (57.5%) than in normal children (70.6%). The duration of time spent outside was again low in both groups but significantly lower in vitamin D deficient children (23.5 minutes) compared to normal children (28.4 minutes). Low duration of time spent outdoors, breast feeding less than 6 months, a family history of diabetes mellitus and physical activity were significant predictors for vitamin D deficiency in Qatari children. Rickets, fractures, gastroenteritis and delayed milestones were all significantly higher in vitamin D deficient children. CONCLUSIONS: The present study revealed that the prevalence of vitamin D deficiency is high in Qatari children and more common in Qatari girls. In the young population in Qatar, vitamin D deficiency appears to result from a combination of limitations in sunlight exposure and a low oral intake of vitamin D.

Tetrahydrobiopterin deficiency in human rabies.

Rabies is a fatal viral encephalitis characterized by a clinically acute and progressive course. With rare exceptions, there is a discrepancy between clinical outcome and frank histological alterations in rabies. Investigators have postulated that rabies virus may modify neurotransmission through occupancy of cellular receptors or alteration of ion channels. We took advantage of these observations to improvise a successful therapy for rabies. The Milwaukee protocol ( www.mcw.edu/rabies ) was further modified to treat two German patients. We measured pterins and monoamine neurotransmitter metabolites in the CSF of patients with rabies by HPLC with electrochemical or fluorescent detection. We report loss of tetrahydrobiopterin (BH(4)) and associated pathological decrease of dopaminergic and serotoninergic neurotransmission in three successive patients with rabies. CSF levels of BH(4) and neurotransmitter metabolites increased in two patients who were supplemented. Our findings support the long-standing speculation of modified neurotransmission in the pathogenesis of rabies, but by another mechanism. Brain turnover of dopamine and serotonin is reduced following rabies-acquired BH(4) deficiency. Neuronal nitric oxide synthase is BH(4)-dependent and may also be involved, possibly causing cerebrovascular insufficiency in one patient. This work must be carefully replicated in animal models and future patients. We are cautiously optimistic at the prospect of readily available, metabolically specific, enteral therapy for rabies.

Pyridoxal phosphate-dependent neonatal epileptic encephalopathy.

Pyridox(am)ine-5'-phosphate oxidase converts pyridoxine phosphate and pyridoxamine phosphate to pyridoxal phosphate, a cofactor in many metabolic reactions, including neurotransmitter synthesis. A family with a mutation in the pyridox(am)ine-5'-phosphate oxidase gene presenting with neonatal seizures unresponsive to pyridoxine and anticonvulsant treatment but responsive to pyridoxal phosphate is described. Pyridoxal phosphate should be considered in neonatal epileptic encephalopathy unresponsive to pyridoxine.

Qualitative urinary organic acid analysis: methodological approaches and performance.

A programme for proficiency testing of biochemical genetics laboratories undertaking urinary qualitative organic acid analysis and its results for 50 samples examined for factors contributing to poor performance are described. Urine samples from patients in whom inherited metabolic disorders have been confirmed as well as control urines were circulated to participants and the results from 94 laboratories were evaluated. Laboratories showed variability both in terms of their individual performance and on a disease-specific basis. In general, conditions including methylmalonic aciduria, propionic aciduria, isovaleric aciduria, mevalonic aciduria, Canavan disease and 3-methylcrotonyl-CoA carboxylase were readily identified. Detection was poorer for other diseases such as glutaric aciduria type II, glyceric aciduria and, in one sample, 3-methylcrotonyl-CoA carboxylase deficiency. To identify the factors that allow some laboratories to perform well on a consistent basis while others perform badly, we devised a questionnaire and compared the responses with the results for performance in the scheme. A trend towards better performance could be demonstrated for those laboratories that regularly use internal quality control (QC) samples in their sample preparation (p = 0.079) and those that participate in further external quality assurance (EQA) schemes (p = 0,040). Clinicians who depend upon these diagnostic services to identify patients with these defects and the laboratories that provide them should be aware of the potential for missed diagnoses and the factors that may lead to improved performance.

Recurrent acute liver failure and mitochondriopathy in a case of Wolcott-Rallison syndrome.

A 10-year-old Arabic boy of consanguineous parents has suffered eight episodes of acute liver failure with haemolysis triggered by intercurrent febrile illnesses. The first crisis occurred at 9 months of age, after which diabetes mellitus developed. By the age of 6 years, short stature, mild myopathy and later skeletal epiphyseal dysplasia also became evident. His psychosocial development and educational achievements have remained within normal limits. While there were no clear biochemical indicators of a mitochondrial disorder, an almost complete deficiency of complex I of the respiratory chain was demonstrated in liver but not in fibroblast or muscle samples. Molecular analysis of the eukaryotic translation initiation factor 2alpha kinase gene (EIF2AK3) demonstrated a homozygous mutation, compatible with a diagnosis of Wolcott-Rallison syndrome (WRS). This patient's course adds a new perspective to the presentation of WRS caused by mutations in the EIF2AK3 gene linking it to mitochondrial disorders: recoverable and recurrent acute liver failure. The findings also illustrate the diagnostic difficulty of mitochondrial disease as it cannot be excluded by muscle or skin biopsy in patients presenting with liver disease. The case also further complicates the decision-making process for liver transplantation in cases of acute liver failure in the context of a possible mitochondrial disorder. Such patients may be more likely to recover spontaneously if a mitochondrial disorder underlies the liver failure, yet without neurological features liver transplantation remains an option.