Loss of CD4+ T cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection.

Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its expression in T cells is disputed. Here, we demonstrate that induction of Arg1 expression is a key feature of lung CD4+ T cells during mouse in vivo influenza infection. Conditional ablation of Arg1 in CD4+ T cells accelerated both virus-specific T helper 1 (Th1) effector responses and its resolution, resulting in efficient viral clearance and reduced lung pathology. Using unbiased transcriptomics and metabolomics, we found that Arg1-deficiency was distinct from Arg2-deficiency and caused altered glutamine metabolism. Rebalancing this perturbed glutamine flux normalized the cellular Th1 response. CD4+ T cells from rare ARG1-deficient patients or CRISPR-Cas9-mediated ARG1-deletion in healthy donor cells phenocopied the murine cellular phenotype. Collectively, CD4+ T cell-intrinsic Arg1 functions as an unexpected rheostat regulating the kinetics of the mammalian Th1 lifecycle with implications for Th1-associated tissue pathologies.

L-serine treatment in patients with GRIN-related encephalopathy: a phase 2A, non-randomized study.

GRIN-related disorders are rare developmental encephalopathies with variable manifestations and limited therapeutic options. Here, we present the first non-randomized, open-label, single-arm trial (NCT04646447) designed to evaluate the tolerability and efficacy of L-serine in children with GRIN genetic variants leading to loss-of-function. In this phase 2A trial, patients aged 2-18 years with GRIN loss-of-function pathogenic variants received L-serine for 52 weeks. Primary end points included safety and efficacy by measuring changes in the Vineland Adaptive Behavior Scales, Bayley Scales, age-appropriate Wechsler Scales, Gross Motor Function-88, Sleep Disturbance Scale for Children, Pediatric Quality of Life Inventory, Child Behavior Checklist and the Caregiver-Teacher Report Form following 12 months of treatment. Secondary outcomes included seizure frequency and intensity reduction and EEG improvement. Assessments were performed 3 months and 1 day before starting treatment and 1, 3, 6 and 12 months after beginning the supplement. Twenty-four participants were enrolled (13 males/11 females, mean age 9.8 years, SD 4.8), 23 of whom completed the study. Patients had GRIN2B, GRIN1 and GRIN2A variants (12, 6 and 5 cases, respectively). Their clinical phenotypes showed 91% had intellectual disability (61% severe), 83% had behavioural problems, 78% had movement disorders and 58% had epilepsy. Based on the Vineland Adaptive Behavior Composite standard scores, nine children were classified as mildly impaired (cut-off score > 55), whereas 14 were assigned to the clinically severe group. An improvement was detected in the Daily Living Skills domain (P = 0035) from the Vineland Scales within the mild group. Expressive (P = 0.005), Personal (P = 0.003), Community (P = 0.009), Interpersonal (P = 0.005) and Fine Motor (P = 0.031) subdomains improved for the whole cohort, although improvement was mostly found in the mild group. The Growth Scale Values in the Cognitive subdomain of the Bayley-III Scale showed a significant improvement in the severe group (P = 0.016), with a mean increase of 21.6 points. L-serine treatment was associated with significant improvement in the median Gross Motor Function-88 total score (P = 0.002) and the mean Pediatric Quality of Life total score (P = 0.00068), regardless of severity. L-serine normalized the EEG pattern in five children and the frequency of seizures in one clinically affected child. One patient discontinued treatment due to irritability and insomnia. The trial provides evidence that L-serine is a safe treatment for children with GRIN loss-of-function variants, having the potential to improve adaptive behaviour, motor function and quality of life, with a better response to the treatment in mild phenotypes.

Impact of citrulline substitution on clinical outcome after liver transplantation in carbamoyl phosphate synthetase 1 and ornithine transcarbamylase deficiency.

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

Altered Serum Proteins Suggest Inflammation, Fibrogenesis and Angiogenesis in Adult Patients with a Fontan Circulation.

Previous omics research in patients with complex congenital heart disease and single-ventricle circulation (irrespective of the stage of palliative repair) revealed alterations in cardiac and systemic metabolism, inter alia abnormalities in energy metabolism, and inflammation, oxidative stress or endothelial dysfunction. We employed an affinity-proteomics approach focused on cell surface markers, cytokines, and chemokines in the serum of 20 adult Fontan patients with a good functioning systemic left ventricle, and we 20 matched controls to reveal any specific processes on a cellular level. Analysis of 349 proteins revealed 4 altered protein levels related to chronic inflammation, with elevated levels of syndecan-1 and glycophorin-A, as well as decreased levels of leukemia inhibitory factor and nerve growth factor-ß in Fontan patients compared to controls. All in all, this means that Fontan circulation carries specific physiological and metabolic instabilities, including chronic inflammation, oxidative stress imbalance, and consequently, possible damage to cell structure and alterations in translational pathways. A combination of proteomics-based biomarkers and the traditional biomarkers (uric acid, γGT, and cholesterol) performed best in classification (patient vs. control). A metabolism- and signaling-based approach may be helpful for a better understanding of Fontan (patho-)physiology. Syndecan-1, glycophorin-A, leukemia inhibitory factor, and nerve growth factor-ß, especially in combination with uric acid, γGT, and cholesterol, might be interesting candidate parameters to complement traditional diagnostic imaging tools and the determination of traditional biomarkers, yielding a better understanding of the development of comorbidities in Fontan patients, and they may play a future role in the identification of targets to mitigate inflammation and comorbidities in Fontan patients.

The Genetic Landscape and Epidemiology of Phenylketonuria.

Phenylketonuria (PKU), caused by variants in the phenylalanine hydroxylase (PAH) gene, is the most common autosomal-recessive Mendelian phenotype of amino acid metabolism. We estimated that globally 0.45 million individuals have PKU, with global prevalence 1:23,930 live births (range 1:4,500 [Italy]-1:125,000 [Japan]). Comparing genotypes and metabolic phenotypes from 16,092 affected subjects revealed differences in disease severity in 51 countries from 17 world regions, with the global phenotype distribution of 62% classic PKU, 22% mild PKU, and 16% mild hyperphenylalaninemia. A gradient in genotype and phenotype distribution exists across Europe, from classic PKU in the east to mild PKU in the southwest and mild hyperphenylalaninemia in the south. The c.1241A>G (p.Tyr414Cys)-associated genotype can be traced from Northern to Western Europe, from Sweden via Norway, to Denmark, to the Netherlands. The frequency of classic PKU increases from Europe (56%) via Middle East (71%) to Australia (80%). Of 758 PAH variants, c.1222C>T (p.Arg408Trp) (22.2%), c.1066-11G>A (IVS10-11G>A) (6.4%), and c.782G>A (p.Arg261Gln) (5.5%) were most common and responsible for two prevalent genotypes: p.[Arg408Trp];[Arg408Trp] (11.4%) and c.[1066-11G>A];[1066-11G>A] (2.6%). Most genotypes (73%) were compound heterozygous, 27% were homozygous, and 55% of 3,659 different genotypes occurred in only a single individual. PAH variants were scored using an allelic phenotype value and correlated with pre-treatment blood phenylalanine concentrations (n = 6,115) and tetrahydrobiopterin loading test results (n = 4,381), enabling prediction of both a genotype-based phenotype (88%) and tetrahydrobiopterin responsiveness (83%). This study shows that large genotype databases enable accurate phenotype prediction, allowing appropriate targeting of therapies to optimize clinical outcome.

Impact of the SARS-CoV-2 pandemic on the health of individuals with intoxication-type metabolic diseases-Data from the E-IMD consortium.

The SARS-CoV-2 pandemic challenges healthcare systems worldwide. Within inherited metabolic disorders (IMDs) the vulnerable subgroup of intoxication-type IMDs such as organic acidurias (OA) and urea cycle disorders (UCD) show risk for infection-induced morbidity and mortality. This study (observation period February 2020 to December 2021) evaluates impact on medical health care as well as disease course and outcome of SARS-CoV-2 infections in patients with intoxication-type IMDs managed by participants of the European Registry and Network for intoxication type metabolic diseases Consortium (E-IMD). Survey's respondents managing 792 patients (n = 479 pediatric; n = 313 adult) with intoxication-type IMDs (n = 454 OA; n = 338 UCD) in 14 countries reported on 59 (OA: n = 36; UCD: n = 23), SARS-CoV-2 infections (7.4%). Medical services were increasingly requested (95%), mostly alleviated by remote technologies (86%). Problems with medical supply were scarce (5%). Regular follow-up visits were reduced in 41% (range 10%-50%). Most infected individuals (49/59; 83%) showed mild clinical symptoms, while 10 patients (17%; n = 6 OA including four transplanted MMA patients; n = 4 UCD) were hospitalized (metabolic decompensation in 30%). ICU treatment was not reported. Hospitalization rate did not differ for diagnosis or age group (p = 0.778). Survival rate was 100%. Full recovery was reported for 100% in outpatient care and 90% of hospitalized individuals. SARS-CoV-2 impacts health care of individuals with intoxication-type IMDs worldwide. Most infected individuals, however, showed mild symptoms and did not require hospitalization. SARS-CoV-2-induced metabolic decompensations were usually mild without increased risk for ICU treatment. Overall prognosis of infected individuals is very promising and IMD-specific or COVID-19-related complications have not been observed.

Recommendations for diagnosing and managing individuals with glutaric aciduria type 1: Third revision.

Glutaric aciduria type 1 is a rare inherited neurometabolic disorder of lysine metabolism caused by pathogenic gene variations in GCDH (cytogenic location: 19p13.13), resulting in deficiency of mitochondrial glutaryl-CoA dehydrogenase (GCDH) and, consequently, accumulation of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid and glutarylcarnitine detectable by gas chromatography/mass spectrometry (organic acids) and tandem mass spectrometry (acylcarnitines). Depending on residual GCDH activity, biochemical high and low excreting phenotypes have been defined. Most untreated individuals present with acute onset of striatal damage before age 3 (to 6) years, precipitated by infectious diseases, fever or surgery, resulting in irreversible, mostly dystonic movement disorder with limited life expectancy. In some patients, striatal damage develops insidiously. In recent years, the clinical phenotype has been extended by the finding of extrastriatal abnormalities and cognitive dysfunction, preferably in the high excreter group, as well as chronic kidney failure. Newborn screening is the prerequisite for pre-symptomatic start of metabolic treatment with low lysine diet, carnitine supplementation and intensified emergency treatment during catabolic episodes, which, in combination, have substantially improved neurologic outcome. In contrast, start of treatment after onset of symptoms cannot reverse existing motor dysfunction caused by striatal damage. Dietary treatment can be relaxed after the vulnerable period for striatal damage, that is, age 6 years. However, impact of dietary relaxation on long-term outcomes is still unclear. This third revision of evidence-based recommendations aims to re-evaluate previous recommendations (Boy et al., J Inherit Metab Dis, 2017;40(1):75-101; Kolker et al., J Inherit Metab Dis 2011;34(3):677-694; Kolker et al., J Inherit Metab Dis, 2007;30(1):5-22) and to implement new research findings on the evolving phenotypic diversity as well as the impact of non-interventional variables and treatment quality on clinical outcomes.

ost in promiscuity? An evolutionary and biochemical evaluation of HSD10 function in cardiolipin metabolism.

Multifunctional proteins are challenging as it can be difficult to confirm pathomechanisms associated with disease-causing genetic variants. The human 17ß-hydroxysteroid dehydrogenase 10 (HSD10) is a moonlighting enzyme with at least two structurally and catalytically unrelated functions. HSD10 disease was originally described as a disorder of isoleucine metabolism, but the clinical manifestations were subsequently shown to be linked to impaired mtDNA transcript processing due to deficient function of HSD10 in the mtRNase P complex. A surprisingly large number of other, mostly enzymatic and potentially clinically relevant functions have been attributed to HSD10. Recently, HSD10 was reported to exhibit phospholipase C-like activity towards cardiolipins (CL), important mitochondrial phospholipids. To assess the physiological role of the proposed CL-cleaving function, we studied CL architectures in living cells and patient fibroblasts in different genetic backgrounds and lipid environments using our well-established LC-MS/MS cardiolipidomic pipeline. These experiments revealed no measurable effect on CLs, indicating that HSD10 does not have a physiologically relevant function towards CL metabolism. Evolutionary constraints could explain the broad range of reported substrates for HSD10 in vitro. The combination of an essential structural with a non-essential enzymatic function in the same protein could direct the evolutionary trajectory towards improvement of the former, thereby increasing the flexibility of the binding pocket, which is consistent with the results presented here.

Altered gut microbiome diversity and function in patients with propionic acidemia.

Propionic acidemia (PA) is an inherited metabolic disorder of propionate metabolism, where the gut microbiota may play a role in pathophysiology and therefore, represent a relevant therapeutic target. Little is known about the gut microbiota composition and activity in patients with PA. Although clinical practice varies between metabolic treatment centers, management of PA requires combined dietary and pharmaceutical treatments, both known to affect the gut microbiota. This study aimed to characterize the gut microbiota and its metabolites in fecal samples of patients with PA compared with healthy controls from the same household. Eight patients (aged 3-14y) and 8 controls (4-31y) were recruited from Center 1 (UK) and 7 patients (11-33y) and 6 controls (15-54y) from Center 2 (Austria). Stool samples were collected 4 times over 3 months, alongside data on dietary intakes and medication usage. Several microbial taxa differed between patients with PA and controls, particularly for Center 1, e.g., Proteobacteria levels were increased, whereas butyrate-producing genera, such as Roseburia and Faecalibacterium, were decreased. Most measured microbial metabolites were lower in patients with PA, and butyrate was particularly depleted in patients from Center 1. Furthermore, microbiota profile of these patients showed the lowest compositional and functional diversity, and lowest stability over 3 months. As the first study to map the gut microbiota of patients with PA, this work represents an important step forward for developing new therapeutic strategies to further improve PA clinical status. New dietary strategies should consider microbial propionate production as well as butyrate production and microbiota stability.

100 years of inherited metabolic disorders in Austria-A national registry of minimal birth prevalence, diagnosis, and clinical outcome of inborn errors of metabolism in Austria between 1921 and 2021.

Inherited metabolic disorders (IMDs) are a heterogeneous group of rare disorders characterized by disruption of metabolic pathways. To date, data on incidence and prevalence of IMDs are limited. Taking advantage of a functioning network within the Austrian metabolic group, our registry research aimed to update the data of the "Registry for Inherited Metabolic Disorders" started between 1985 and 1995 with retrospectively retrieved data on patients with IMDs according to the Society for the Study of Inborn Errors of Metabolism International Classification of Diseases 11 (SSIEM ICD11) catalogue. Included in this retrospective register were 2631 patients with an IMD according to the SSIEM ICD11 Classification, who were treated in Austria. Thus, a prevalence of 1.8/10 000 for 2020 and a median minimal birth prevalence of 16.9/100 000 (range 0.7/100 000-113/100 000) were calculated for the period 1921 to February 2021. We detected a male predominance (m:f = 1.2:1) and a mean age of currently alive patients of 17.6 years (range 5.16 months-100 years). Most common diagnoses were phenylketonuria (17.7%), classical galactosaemia (6.6%), and biotinidase deficiency (4.2%). The most common diagnosis categories were disorders of amino acid and peptide metabolism (819/2631; 31.1%), disorders of energy metabolism (396/2631; 15.1%), and lysosomal disorders (395/2631; 15.0%). In addition to its epidemiological relevance, the "Registry for Inherited Metabolic Disorders" is an important tool for enhancing an exchange between care providers. Moreover, by pooling expertise it prospectively improves patient treatment, similar to pediatric oncology protocols. A substantial requirement for ful filling this goal is to regularly update the registry and provide nationwide coverage with inclusion of all medical specialties.

The Manchester Triage System in a Pediatric Emergency Department of an Austrian University Hospital: A Retrospective Analysis of Urgency Levels.

OBJECTIVES: The Manchester Triage System (MTS) has entered widespread international use in emergency departments (EDs). This retrospective study analyzes urgency of patient visits (PV) at the ED of the Clinic for Pediatrics at the Medical University of Innsbruck. METHODS: We collected demographic and outcome information, including PV urgency levels (UL) according to the MTS, for 3 years (2015-2018), separating PV during regular office hours (ROH; 8:00 am to 5:00 pm) from PV during afternoon and night hours (5:00 pm to 8:00 am), and PV on weekdays from PV on weekends and bank holidays (WE). RESULTS: A total of 56,088 PV were registered with a UL. Most (68.4%) PV were classified as nonurgent. During ROH, more PV per hour (PV/h) were recorded than during afternoon and night hours (3.0 PV/h vs 1.6 PV/h), with a higher proportion of less urgent cases during ROH. On WE, the amount of PV/h was higher than on weekdays (3.6 PV/h vs 2.8 PV/h), with a higher proportion of nonurgent cases (74.6% vs 68.6%). Likelihoods of inpatient admission and hospital stay lengths increased in step with UL. CONCLUSIONS: The MTS proved useful for delineating UL distributions. The MTS analyses may be of value in managing EDs. Prompted by the results of our study, a general practice pediatric care unit was established to support the ED during WE.

Bi-allelic ADPRHL2 Mutations Cause Neurodegeneration with Developmental Delay, Ataxia, and Axonal Neuropathy.

ADP-ribosylation is a reversible posttranslational modification used to regulate protein function. ADP-ribosyltransferases transfer ADP-ribose from NAD+ to the target protein, and ADP-ribosylhydrolases, such as ADPRHL2, reverse the reaction. We used exome sequencing to identify five different bi-allelic pathogenic ADPRHL2 variants in 12 individuals from 8 families affected by a neurodegenerative disorder manifesting in childhood or adolescence with key clinical features including developmental delay or regression, seizures, ataxia, and axonal (sensori-)motor neuropathy. ADPRHL2 was virtually absent in available affected individuals' fibroblasts, and cell viability was reduced upon hydrogen peroxide exposure, although it was rescued by expression of wild-type ADPRHL2 mRNA as well as treatment with a PARP1 inhibitor. Our findings suggest impaired protein ribosylation as another pathway that, if disturbed, causes neurodegenerative diseases.

Bi-allelic Mutations in the Mitochondrial Ribosomal Protein MRPS2 Cause Sensorineural Hearing Loss, Hypoglycemia, and Multiple OXPHOS Complex Deficiencies.

Biogenesis of the mitochondrial oxidative phosphorylation system, which produces the bulk of ATP for almost all eukaryotic cells, depends on the translation of 13 mtDNA-encoded polypeptides by mitochondria-specific ribosomes in the mitochondrial matrix. These mitoribosomes are dual-origin ribonucleoprotein complexes, which contain mtDNA-encoded rRNAs and tRNAs and ∼80 nucleus-encoded proteins. An increasing number of gene mutations that impair mitoribosomal function and result in multiple OXPHOS deficiencies are being linked to human mitochondrial diseases. Using exome sequencing in two unrelated subjects presenting with sensorineural hearing impairment, mild developmental delay, hypoglycemia, and a combined OXPHOS deficiency, we identified mutations in the gene encoding the mitochondrial ribosomal protein S2, which has not previously been implicated in disease. Characterization of subjects' fibroblasts revealed a decrease in the steady-state amounts of mutant MRPS2, and this decrease was shown by complexome profiling to prevent the assembly of the small mitoribosomal subunit. In turn, mitochondrial translation was inhibited, resulting in a combined OXPHOS deficiency detectable in subjects' muscle and liver biopsies as well as in cultured skin fibroblasts. Reintroduction of wild-type MRPS2 restored mitochondrial translation and OXPHOS assembly. The combination of lactic acidemia, hypoglycemia, and sensorineural hearing loss, especially in the presence of a combined OXPHOS deficiency, should raise suspicion for a ribosomal-subunit-related mitochondrial defect, and clinical recognition could allow for a targeted diagnostic approach. The identification of MRPS2 as an additional gene related to mitochondrial disease further expands the genetic and phenotypic spectra of OXPHOS deficiencies caused by impaired mitochondrial translation.

Project "Backtoclinic I": An overview on the state of care of adult PKU patients in Austria.

BACKGROUND: High rates of lost to follow-up (LTFU) adult patients are a major concern in the long-term management of phenylketonuria (PKU). To address this issue, we designed the project "Backtoclinic" with the purpose of identifying LTFU adult PKU patients in Austria as a first step to reestablish appropriate treatment. SUBJECTS AND METHODS: Individuals born between 1966 and 1999 and diagnosed with PKU through the National Austrian Newborn Screening Program (NANSP) were identified using the NANSP's database. Follow-up data were collected in the Austrian metabolic centers (Medical University of Vienna, Graz, Innsbruck and Salzburg). Patients with no contact to any of these centers within the previous two years were classified as LTFU. Epidemiological characteristics of the whole study population as well as of LTFU- and currently in follow-up patients were analyzed. RESULTS: Between 1966 and 1999, 281 individuals were diagnosed with PKU through the NANSP. Two patients died in their first year of life and were excluded from the analysis. Of the remaining 279 patients (mean age ± SD: 36.7 ± 9.1 y, 42.7% females), 177 (63.4%) are currently LTFU. The rate of LTFU patients is higher in men than in women (68.1% vs 57.5%), and markedly increases with age in both sexes. The gender gap is greatest in young adults (52.6% vs. 25.0% in the age range 20.0-24.9 y) and declines with age (94.4% vs. 80.0% in the age range > 45.0 y). CONCLUSIONS: We found an alarming rate of 63.4% of LTFU adult PKU patients in Austria, and observed a gender gap in the PKU state of care. Our findings illustrate the urgent need for the metabolic community to identify LTFU adult PKU patients and to develop strategies to reestablish appropriate treatment for men and women with PKU.

Guidelines for the diagnosis and management of methylmalonic acidaemia and propionic acidaemia: First revision.

Isolated methylmalonic acidaemia (MMA) and propionic acidaemia (PA) are rare inherited metabolic diseases. Six years ago, a detailed evaluation of the available evidence on diagnosis and management of these disorders has been published for the first time. The article received considerable attention, illustrating the importance of an expert panel to evaluate and compile recommendations to guide rare disease patient care. Since that time, a growing body of evidence on transplant outcomes in MMA and PA patients and use of precursor free amino acid mixtures allows for updates of the guidelines. In this article, we aim to incorporate this newly published knowledge and provide a revised version of the guidelines. The analysis was performed by a panel of multidisciplinary health care experts, who followed an updated guideline development methodology (GRADE). Hence, the full body of evidence up until autumn 2019 was re-evaluated, analysed and graded. As a result, 21 updated recommendations were compiled in a more concise paper with a focus on the existing evidence to enable well-informed decisions in the context of MMA and PA patient care.

Subdural Hygroma in an Infant with Marfan's Syndrome.

Based on a patient encounter in which genetically confirmed Marfan's syndrome (MFS) underlay a spontaneously resolving subdural hygroma (SDHy) diagnosed in infancy, we review the literature of MFS clinically manifest in early life (early-onset MFS [EOMFS]) and of differential diagnoses of SDHy and subdural hemorrhage (SDHe) at this age. We found that rare instances of SDHy in the infant are associated with EOMFS. The most likely triggers are minimal trauma in daily life or spontaneous intracranial hypotension. The differential diagnosis of etiologies of SDHy include abusive and nonabusive head trauma, followed by perinatal events and infections. Incidental SDHy and benign enlargement of the subarachnoid spaces must further be kept in mind. SDHy exceptionally also may accompany orphan diseases. Thus, in the infant, EOMFS should be considered as a cause of SDHe and/or SDHy. Even in the absence of congestive heart failure, the combination of respiratory distress syndrome, muscular hypotonia, and joint hyperflexibility signals EOMFS. If EOMFS is suspected, monitoring is indicated for development of SDHe and SDHy with or without macrocephaly. Close follow-up is mandatory.

Lipidomic and Proteomic Alterations Induced by Even and Odd Medium-Chain Fatty Acids on Fibroblasts of Long-Chain Fatty Acid Oxidation Disorders.

Medium-chain fatty acids (mc-FAs) are currently applied in the treatment of long-chain fatty acid oxidation disorders (lc-FAOD) characterized by impaired ß-oxidation. Here, we performed lipidomic and proteomic analysis in fibroblasts from patients with very long-chain acyl-CoA dehydrogenase (VLCADD) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHADD) deficiencies after incubation with heptanoate (C7) and octanoate (C8). Defects of ß-oxidation induced striking proteomic alterations, whereas the effect of treatment with mc-FAs was minor. However, mc-FAs induced a remodeling of complex lipids. Especially C7 appeared to act protectively by restoring sphingolipid biosynthesis flux and improving the observed dysregulation of protein homeostasis in LCHADD under control conditions.

Method comparison of HPLC-ninhydrin-photometry and UHPLC-PITC-tandem mass spectrometry for serum amino acid analyses in patients with complex congenital heart disease and controls.

INTRODUCTION: Metabolomics studies are not routine when quantifying amino acids (AA) in congenital heart disease (CHD). OBJECTIVES: Comparative analysis of 24 AA in serum by traditional high-performance liquid chromatography (HPLC) based on ion exchange and ninhydrin derivatisation followed by photometry (PM) with ultra-high-performance liquid chromatography and phenylisothiocyanate derivatisation followed by tandem mass spectrometry (TMS); interpretation of findings in CHD patients and controls. METHODS: PM: Sample analysis as above (total run time, ~ 119 min). TMS: Sample analysis by AbsoluteIDQ® p180 kit assay (BIOCRATES Life Sciences AG, Innsbruck, Austria), which employs PITC derivatisation; separation of analytes on a Waters Acquity UHPLC BEH18 C18 reversed-phase column, using water and acetonitrile with 0.1% formic acid as the mobile phases; and quantification on a Triple-Stage Quadrupole tandem mass spectrometer (Thermo Fisher Scientific, Waltham, MA) with electrospray ionisation in the presence of internal standards (total run time, ~ 8 min). Calculation of coefficients of variation (CV) (for precision), intra- and interday accuracies, limits of detection (LOD), limits of quantification (LOQ), and mean concentrations. RESULTS: Both methods yielded acceptable results with regard to precision (CV < 10% PM, < 20% TMS), accuracies (< 10% PM, < 34% TMS), LOD, and LOQ. For both Fontan patients and controls AA concentrations differed significantly between methods, but patterns yielded overall were parallel. CONCLUSION: Serum AA concentrations differ with analytical methods but both methods are suitable for AA pattern recognition. TMS is a time-saving alternative to traditional PM under physiological conditions as well as in patients with CHD. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier NCT03886935, date of registration March 27th, 2019 (retrospectively registered).

Stereotactic radiofrequency ablation of a variety of liver masses in children.

BACKGROUND AND AIMS: Surgical resection is currently the cornerstone of liver tumor treatment in children. In adults radiofrequency ablation (RFA) is an established minimally invasive treatment option for small focal liver tumors. Multiprobe stereotactic RFA (SRFA) with intraoperative image fusion to confirm ablation margins allows treatment for large lesions. We describe our experience with SRFA in children with liver masses. METHODS: SRFA was performed in 10 patients with a median age of 14 years (range 0.5-17.0 years) suffering from liver adenoma (n = 3), hepatocellular carcinoma (n = 1), hepatoblastoma (n = 2), myofibroblastic tumor (n = 1), hepatic metastases of extrahepatic tumors (n = 2) and infiltrative hepatic cysts associated with alveolar echinococcosis (n = 1). Overall, 15 lesions with a mean lesion size of 2.6 cm (range 0.7-9.5 cm) were treated in 11 sessions. RESULTS: The technical success rate was 100%, as was the survival rate. No transient adverse effects higher than grade II (Clavien and Dindo) were encountered after interventions. The median hospital stay was 5 d (range 2-33 d). In two patients who subsequently underwent transplant hepatectomy complete ablation was histologically confirmed. Follow-up imaging studies (median 55 months, range 18-129 months) revealed no local or distant recurrence of disease in any patient. CONCLUSIONS: SRFA is an effective minimal-invasive treatment option in pediatric patients with liver tumors of different etiologies.

The value of axillary skin electron microscopic analysis in the diagnosis of lysosomal storage disorders.

Both lysosomal storage diseases and mitochondrial diseases are a group of genetic-inherited metabolic disorders. In an era, where "old fashioned methods" are apparently being replaced by evolving molecular techniques (i.e. exome and whole genome sequencing), the "old fashioned methods" might help to characterise and thus narrow down the potential differential diagnosis. Therefore, we retrospectively evaluated the relevance of electron microscopy of axillary skin for the diagnosis of lysosomal storage or mitochondrial diseases (=inherited metabolic disorders of energy metabolism). Methods and patients: We included 74 patients with developmental delay with regression or neurodegeneration who underwent an axillary skin biopsy for both fibroblast culture and electron microscopy. Because of insufficient skin biopsy quality, for 8 patients no electron microscopy result was obtained. The electron microscopy biopsies revealed abnormalities in 37/66 (56.1%) patients. 29/66 electron microscopy biopsies showed normal results. A definite diagnosis was established in 21/66 (31.8%) patients with a pathological results of axillary skin electron microscopy analysis. In total, in 25/66 (37.8%) of the patients who underwent an axillary skin electron microscopy analysis, a definite diagnosis was finally established. Taking an axillary skin biopsy during anaesthesia or with use of local intradermal lidocaine application is an inexpensive alternative and useful to establish a diagnosis in patients suspected to have a lysosomal storage disease (or inherited metabolic disorder of energy metabolism).