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Background: Some inborn errors of metabolism (IEMs) resulting in aberrations to blood leucine and ammonia levels are commonly treated with kidney replacement therapy (KRT). Children with IEMs require prompt treatment, as delayed treatment results in increased neurological and developmental morbidity., Objectives: Our systematic review in neonates and pediatrics evaluates survival rates and reductions in ammonia and leucine levels across different KRT modalities (continuous KRT (CKRT), hemodialysis (HD), peritoneal dialysis (PD))., Data Sources: A literature search was conducted through PubMed, Web of Science, and Embase databases for articles including survival rate and toxic metabolite clearance data in pediatric patients with IEM undergoing KRT., Study Eligibility Criteria: Cross-sectional, prospective, and retrospective studies with survival rates reported in patients with IEM with an intervention of CKRT, PD, or HD were included. Studies with patients receiving unclear or multiple KRT modalities were excluded., Study Appraisal and Synthesis Methods: Analysis variables included efficacy outcomes [% reduction in ammonia (RIA) from pre- to post-dialysis and time to 50% RIA] and mortality. The Newcastle Ottawa Risk of Bias quality assessment was used to assess bias. All statistical analyses were performed with MedCalc Statistical Software version 19.2.6., Results: A total of 37 studies (n = 642) were included. The pooled proportion (95% CI) of mortality on CKRT was 24.84% (20.93-29.08), PD was 34.42% (26.24-43.33), and HD 34.14% (24.19-45.23). A lower trend of pooled (95% CI) time to 50% RIA was observed with CKRT [6.5 (5.1-7.8)] vs. PD [14.4 (13.3-15.5)]. A higher mortality was observed with greater plasma ammonia level before CKRT (31.94% for ≥ 1000 µmol/L vs. 15.04% for < 1000 µmol/L)., Conclusions and Implications of Key Findings: Despite the limitations in sample size, trends emerged suggesting that CKRT may be associated with lower mortality rates compared to HD or PD, with potential benefits including prevention of rebound hyperammonemia and improved hemodynamic control. While HD showed a trend towards faster achievement of 50% RIA, all modalities demonstrated comparable efficacy in reducing ammonia and leucine levels., Prospero Registration: CRD42023418842., Competing Interests: Declarations Statement of ethics Not applicable. Consent for publication Not applicable. Conflict of interest The authors presented no conflicts of interest., (© 2024. The Author(s).)

Background: Rare disorders comprise of ~ 7500 different conditions affecting multiple systems. Diagnosis of rare diseases is complex due to dearth of specialized medical professionals, testing labs and limited therapeutic options. There is scarcity of data on the prevalence of rare diseases in different populations. India being home to a large population comprising of 4600 population groups, of which several thousand are endogamous, is likely to have a high burden of rare diseases. The present study provides a retrospective overview of a cohort of patients with rare genetic diseases identified at a tertiary genetic test centre in India., Results: Overall, 3294 patients with 305 rare diseases were identified in the present study cohort. These were categorized into 14 disease groups based on the major organ/ organ system affected. Highest number of rare diseases (D = 149/305, 48.9%) were identified in the neuromuscular and neurodevelopmental (NMND) group followed by inborn errors of metabolism (IEM) (D = 47/305; 15.4%). Majority patients in the present cohort (N = 1992, 61%) were diagnosed under IEM group, of which Gaucher disease constituted maximum cases (N = 224, 11.2%). Under the NMND group, Duchenne muscular dystrophy (N = 291/885, 32.9%), trinucleotide repeat expansion disorders (N = 242/885; 27.3%) and spinal muscular atrophy (N = 141/885, 15.9%) were the most common. Majority cases of β-thalassemia (N = 120/149, 80.5%) and cystic fibrosis (N = 74/75, 98.7%) under the haematological and pulmonary groups were observed, respectively. Founder variants were identified for Tay-Sachs disease and mucopolysaccharidosis IVA diseases. Recurrent variants for Gaucher disease (GBA:c.1448T > C), β-thalassemia (HBB:c.92.+5G > C), non-syndromic hearing loss (GJB2:c.71G > A), albinism (TYR:c.832 C > T), congenital adrenal hyperplasia (CYP21A2:c.29-13 C > G) and progressive pseudo rheumatoid dysplasia (CCN6:c.298T > A) were observed in the present study., Conclusion: The present retrospective study of rare disease patients diagnosed at a tertiary genetic test centre provides first insight into the distribution of rare genetic diseases across the country. This information will likely aid in drafting future health policies, including newborn screening programs, development of target specific panel for affordable diagnosis of rare diseases and eventually build a platform for devising novel treatment strategies for rare diseases., (© 2024. The Author(s).)

Background: Classical homocystinuria is an inborn amino acid metabolism disorder resulting from mutations in the Cystathionine-β-Synthase (CBS) gene. These mutations lead to elevated homocysteine and methionine levels and reduced cysteine levels in the blood. Typically, diagnosis occurs after patients display symptoms, and various lab methods confirm it. DNA sequencing is the best option for early detection of genetic variants in asymptomatic suspected individuals. Unfortunately, its high cost can hinder its use, especially in low-income countries like Pakistan., Objective: Aim of this study was to devise a robust low-cost diagnostic/screening assay based on Tetra-ARMS-PCR for five prevalent genetic variants found in Pakistani classical homocystinuria patients., Materials and Methods: In the current study, T-ARMS-PCR assays were developed for five mutations (c.975G > C, c.770C > T, c.752T > C, c.1039 + 1G > T, c.451 + 1GG > TA), which were characterized previously in classical homocystinuria patients. These low-cost T-ARMS-PCR assays were then used to screen the affected individuals and their family members to identify their genotypes for pathogenic variations in the asymptomatic patients and carriers in their respective families., Results: The outcomes were entirely consistent with those obtained from Sanger DNA sequencing, confirming the sensitivity, specificity, and reliability of the T-ARMS-PCR assay for detecting CBS mutations., Conclusion: T-ARMS-PCR has wide applications for low-income countries for the screening and early diagnosis of asymptomatic patients and carriers in the homocystinuria affected families as well as other inherited diseases.

Inborn errors of metabolism (IEMs) are inherited biochemical/metabolic disorders that are commonly present in the immediate neonatal period. The aim of this retrospective study was to determine the incidence and distribution of IEMs in newborn infants delivered in our hospital and to evaluate its outcome. A total of 16 494 (99.9%) newborn infants were screened for IEMs. We found 29 newborn infants diagnosed with IEMs, representing an incidence of 1 per ~569 live births and a cumulative incidence of 176 per 100 000 live births of the IEM-positive newborn infants. We detected 11 different types of IEMs, and the top 6 categories were endocrinopathies followed by carbohydrates disorders, vitamin-responsive disorders, organic acid defects, and ketogenesis and ketolysis defects. This study does reflect upon the importance of educating the general population about the perils of Consanguineous Marriages (CMs) in order to reduce related disorders significantly, especially in families who have a history of IEMs., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

(AAV)-mediated episomal gene replacement therapy for monogenic liver disorders is currently limited in pediatric settings due to the loss of vector DNA, associated with hepatocyte duplication during liver growth. Genome editing is a promising strategy leading to a permanent and specific genome modification that is transmitted to daughter cells upon proliferation. Using genome targeting, we previously rescued neonatal lethality in mice with Crigler-Najjar syndrome. This rare monogenic disease is characterized by severe neonatal unconjugated hyperbilirubinemia, neurological damage, and death. Here, using the CRISPR- Staphylococcus aureus Cas9 ( Sa Cas9) platform, we edited the disease-causing mutation present in the Ugt1a locus of these mice. Newborn mice were treated with two AAV8 vectors: one expressing the Sa Cas9 and single guide RNA, and the other carrying the Ugt1a homology regions with the corrected sequence, while maintained in a temporary phototherapy setting rescuing mortality. We observed a 50% plasma bilirubin reduction that remained stable for up to 6 months. We then tested different Cas9:donor vector ratios, with a 1:5 ratio showing the greatest efficacy in lowering plasma bilirubin, with partial lethality rescue when more severe, lethal conditions were applied. In conclusion, we reduced plasma bilirubin to safe levels and partially rescued neonatal lethality by correcting the mutant Ugt1a1 gene of a Crigler-Najjar mouse model., Competing Interests: G.B. and A.F.M. are inventors of patents describing liver gene transfer approaches for metabolic diseases and/or treatment of hyperbilirubinemia. The remaining authors declare no competing interests., (© 2023 The Author(s).)

The advances in the field of inborn errors of metabolism (IEM) are spectacular. New IEM have been described, their pathophysiological bases and implications for the organism are better known. With the advent of new metabolomics, lipidomics and genomics techniques, advances in diagnosis have multiplied and allow new therapeutic options to be explored. A new IEM classification has been established based on the more than 1.450 IEM identified. A new specialty is emerging, which is metabolic medicine. Neonatal screening is becoming universal and allows us today, with tandem mass, to diagnose more than 20 metabolic diseases of the neonatal period, with treatment options. IEM units for adults are being created to follow-up children with IEM who survive the disease and with an increasingly better quality of life, and some IEM that start in adolescence or adulthood are diagnosed. Personalized therapies and clinical practice guidelines appear for any IEM. Finally, new therapeutic options are emerging day to day that allow a longer survival and better quality of life. Conventional gene therapy is already being applied in some IEM. However, gene editing strategies with RNA therapies may allow the correction of the genetic mutation, minimizing the problems associated with conventional compensation gene therapy.

Objective: To evaluate the knowledge and experiences of healthcare workers in the management of neurometabolic disorders., Methods: A cross-sectional study was carried out among the 132 participants of a continued medical education program conducted in the Department of Pediatrics at a tertiary-care teaching hospital. A questionnaire-based feedback form was circulated among the participants, and their responses were analyzed., Results: Ninety-three responses were analyzed. The most common pediatric illnesses identified were infections (91%), nutritional (91%), birth-related injuries (44.4%) and metabolic disorders (44.4%). Consanguinity (81.5%) and genetic heterogeneity (42.4%) were recognized as most important causes of neurometabolic disorders. Important steps identified for prevention were prenatal testing (65.6%) and newborn screening at birth (61%); while for improving the diagnosis were routine availability of metabolic investigations (65.3%) and screening at birth (46.6%). Most respondents (58.7%) expressed discomfort in managing a case with inherited metabolic defect due to a lack of knowledge (46.8%) and diagnostic facilities (44.6%). Despite access to testing in the majority, a high cost of testing was noticed for biochemical and genetic investigations. The majority of participants (73%) considered some of the inherited metabolic disorders as treatable. Dietary substitution (89.3%), enzyme replacement (69%), cofactor replacement (53.6%), gene therapy (35.7%) and regular dialysis (16.7%) were considered the treatment options., Conclusion: In spite of growing awareness of inherited metabolic disorders, there are still gaps in knowledge among healthcare workers. It is challenging to diagnose and manage these disorders. Cost-reduction of diagnostic tests, routine newborn screening and increased educational activities are key challenges to be addressed., (© The Author(s) [2023]. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: The incidence of inborn errors of metabolism (IEM) varies across countries and areas. Currently, there are no studies on IEM using newborn screening (NBS) in eastern coastal areas of China. We aimed to estimate the incidence and genetic variants of IEM and understand the spectrum of diseases caused by IEM and variants among them in this area., Methods: The NBS performed by tandem mass spectrometry (MS/MS) from 2016 to 2021 was retrospectively reviewed. Heel blood was collected from all newborns 72 h after birth. Targeted massively parallel sequencing was performed for genetic analysis., Results: Among 245,194 newborns, 95 were diagnosed with IEM, the overall incidence observed was-IEM: 1/2581; amino acid metabolism disorder: 1/4715; organic acid metabolism disorder: 1/11676; and fatty acid metabolism disorder: 1/11145. The incidence of different IEM was in the range of 1/245194 to 1/6452. Phenylketonuria (PKU, 1/7211) was the most common IEM, followed by methylmalonic acidemia (MMA, 1/27244), short-chain acyl-CoA dehydrogenase deficiency (SCADD, 1/30649), and citrin deficiency (CD, 1/35028). For genetic variants, the common hotspot variants found were-PAH gene for PKU: c.728G > A, c.442-1G > A, c.611A > G, c.721C > T; PTS gene for non-classical PKU: c.259C > T; MMACHC gene for MMA: c.658&#95;660delAAG, c.609G > A; MMUT gene for MMA: c.1663G > A; ACADS gene for SCADD: c.1031A > G and c.1130C > T; and SLC25A13 gene for CD: c.1638&#95;1660dup, c.852&#95;855del., Conclusion: This study displayed the diseases and varied spectrum of IEM in eastern coastal areas of China. Implementing NBS for IEM by MS/MS combined with massively parallel sequencing can offer an improved plan for NBS to detect IEM., (© 2023 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

There are about 1500 genetic metabolic diseases. A small number of treatable diseases are diagnosed by newborn screening programs, which are continually being developed. However, most diseases can only be diagnosed based on clinical symptoms or metabolic findings. The main biological fluids used are urine, plasma and, in special situations, cerebrospinal fluid. In contrast to commonly used methods such as gas chromatography and high performance liquid chromatography mass spectrometry, ex vivo proton spectroscopy ( 1 H-NMR) is not yet used in routine clinical practice, although it has been recommended for more than 30 years. Automatic analysis and improved NMR technology have also expanded the applications used for the diagnosis of inborn errors of metabolism. We provide a mini-overview of typical applications, especially in urine but also in plasma, used to diagnose common but also rare genetic metabolic diseases with 1 H-NMR. The use of computer-assisted diagnostic suggestions can facilitate interpretation of the profiles. In a proof of principle, to date, 182 reports of 59 different diseases and 500 reports of healthy children are stored. The percentage of correct automatic diagnoses was 74%. Using the same 1 H-NMR profile-targeted analysis, it is possible to apply an untargeted approach that distinguishes profile differences from healthy individuals. Thus, additional conditions such as lysosomal storage diseases or drug interferences are detectable. Furthermore, because 1 H-NMR is highly reproducible and can detect a variety of different substance categories, the metabolomic approach is suitable for monitoring patient treatment and revealing additional factors such as nutrition and microbiome metabolism. Besides the progress in analytical techniques, a multiomics approach is most effective to combine metabolomics with, for example, whole exome sequencing, to also diagnose patients with nondetectable metabolic abnormalities in biological fluids. In this mini review we also provide our own data to demonstrate the role of NMR in a multiomics platform in the field of inborn errors of metabolism., (© 2022 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

Untargeted metabolomics (UM) is increasingly being deployed as a strategy for screening patients that are suspected of having an inborn error of metabolism (IEM). In this study, we examined the potential of existing outlier detection methods to detect IEM patient profiles. We benchmarked 30 different outlier detection methods when applied to three untargeted metabolomics datasets. Our results show great differences in IEM detection performances across the various methods. The methods DeepSVDD and R-graph performed most consistently across the three metabolomics datasets. For datasets with a more balanced number of samples-to-features ratio, we found that AE reconstruction error , Mahalanobis and PCA reconstruction error also performed well. Furthermore, we demonstrated the importance of a PCA transform prior to applying an outlier detection method since we observed that this increases the performance of several outlier detection methods. For only one of the three metabolomics datasets, we observed clinically satisfying performances for some outlier detection methods, where we were able to detect 90% of the IEM patient samples while detecting no false positives. These results suggest that outlier detection methods have the potential to aid the clinical investigator in routine screening for IEM using untargeted metabolomics data, but also show that further improvements are needed to ensure clinically satisfying performances.

Objective: To assess the outcomes of neonates in a contemporary multi-institutional cohort who receive renal replacement therapy (RRT) for hyperammonemia., Study Design: We performed a retrospective analysis of 51 neonatal patients with confirmed inborn errors of metabolism that were treated at 9 different children's hospitals in the US between 2000 and 2015., Results: Twenty-nine patients received hemodialysis (57%), 21 patients received continuous renal replacement therapy (41%), and 1 patient received peritoneal dialysis (2%). The median age at admission of both survivors (n = 33 [65%]) and nonsurvivors (n = 18) was 3 days. Peak ammonia and ammonia at admission were not significantly different between survivors and nonsurvivors. Hemodialysis, having more than 1 indication for RRT in addition to hyperammonemia, and complications during RRT were all risk factors for mortality. After accounting for multiple patient factors by multivariable analyses, hemodialysis was associated with a higher risk of death compared with continuous renal replacement therapy. When clinical factors including evidence of renal dysfunction, number of complications, concurrent extracorporeal membrane oxygenation, vasopressor requirement, and degree of hyperammonemia were held constant in a single Cox regression model, the hazard ratio for death with hemodialysis was 4.07 (95% CI 0.908-18.2, P value = .067). To help providers caring for neonates with hyperammonemia understand their patient's likelihood of survival, we created a predictive model with input variables known at the start of RRT., Conclusions: Our large, multicenter retrospective review supports the use of continuous renal replacement therapy for neonatal hyperammonemia., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: To study the clinicoetiological profile of children presenting with acute noninfectious encephalopathy (NIE) and identify the proportion of children having inborn errors of metabolism (IEM)., Method: This descriptive cross sectional study was conducted in a tertiary care centre in Northern India. Consecutive children, aged more than 28 d and less than 12 y, with acute encephalopathy were enrolled after ruling out CNS infection. All children were evaluated on an internally validated structured proforma. A sequential pre-decided battery of tests was applied to determine the cause of encephalopathy. IEM suspects were subjected to TMS/GCMS followed by mutation analysis for confirmation., Results: Fifty children with noninfectious encephalopathy (NIE) were recruited and metabolic causes were detected in 9 of these children (18%), aged 3 to 42 mo, with female preponderance. The IEMs included lactic acidosis (4), glutaric aciduria (3), isovaleric academia (1), and hyperhomocysteinemia (1). History of previously affected siblings and consanguinity between the parents were important indicators of IEM. MS/MS and mutation analysis were the mainstay of diagnosis in these patients. IEMs contributed to the most common cause amongst cases of NIE., Conclusion: IEMs constitute a significant proportion of NIE in India and a high index of suspicion is required to make the diagnosis., (© 2022. Dr. K C Chaudhuri Foundation.)

We have developed a fast and accurate method that uses a small volume of sample to determine over 25 of the typically reported amino acids in human plasma. Samples were prepped with a single step using a spin filter to remove proteins, avoiding the decreased sensitivity from dilution in acid precipitation. Using a reverse phase (RP) High Performance Liquid Chromatography (HPLC) system with O-phthaldehyde (OPA) as the pre-column derivatization reagent, and UV detection at 338 nm, we did a direct comparison with the most common ion exchange/ninhydrin method used in clinical labs on the same plasma samples with 95% concurrence, analysis of amino acid standard solutions returned 99% concurrence. With a sample preparation time of 30 min, utilizing less than 25 μl of sample and with a chromatography run of 30 min, this method can substantially increase access to analysis in both clinical and research laboratories using instruments that are more widely available., Synopsis: We describe a rapid and easily deployed method for sensitive amino measurement in biological samples., (© 2022 The Authors.)

Introduction: Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by a deficiency of acid β-glucosidase encoded by the GBA gene. In patients with GD, childhood onset parkinsonian features have been rarely described., Methods: Twin siblings with GD are described, including clinical follow-up and treatment response. Bone marrow, enzyme activity studies and genotyping were performed., Results: By age 9 months, symptoms at onset were thrombocytopenia and splenomegaly. By age 2, hypokinesia, bradykinesia and oculomotor apraxia were observed. By age 5 a complete rigid hypokinetic syndrome was stablished in both patients, including bradykinesia, tremor and rigidity. Treatment with imiglucerase, miglustat, ambroxol and levodopa were performed. Levodopa showed a good response with improvement in motor and non-motor skills. Foamy cells were found in the bone marrow study. Glucocerebrosidase activity was 28% and 26%. Sanger sequencing analysis identified a missense mutation and a complex allele (NP&#95;000148: p.[(Asp448His)]; [(Leu422Profs*4)]) in compound heterozygosity in GBA gene., Conclusions: Two siblings with neuronopathic GD with an intermediate form between type 2 and 3, with a systemic and neurological phenotype are described. The complex neurological picture included a hypokinetic-rigid and tremor syndrome that improved with levodopa treatment. These conditions together have not been previously described in pediatric GD. We suggest that in children with parkinsonian features, lysosomal storage disorders must be considered, and a levodopa trial must be performed. Moreover, this report give support to the finding that GBA and parkinsonian features share biological pathways and highlight the importance of lysosomal mechanisms in parkinsonism pathogenesis, what might have therapeutic implications., (Copyright © 2021. Published by Elsevier Ltd.)

Introduction: Ineffective esophageal motility (IEM) is a physiologic diagnosis and is a component of the Chicago Classification. It has a strong association with gastroesophageal reflux and may be found during work-up for anti-reflux surgery. IEM implies a higher risk of post-op dysphagia if a total fundoplication is done. We hypothesized that IEM is not predictive of dysphagia following fundoplication and that it is safe to perform total fundoplication in appropriately selected patients., Methods: Retrospective chart review of patients who underwent total fundoplication between September 2012 and December 2018 in a single foregut surgery center and who had IEM on preoperative manometry. We excluded patients who had partial fundoplication, previous foregut surgery, other causes of dysphagia or an esophageal lengthening procedure. Dysphagia was assessed using standardized Dakkak score ≤ 40 and GERD-HRQL question 7 ≥ 3., Results: Two hundred patients were diagnosed with IEM and 31 met the inclusion criteria. Median follow-up: 706 days (IQR 278-1348 days). No preoperative factors, including subjective dysphagia, transit on barium swallow, or individual components of manometry showed statistical correlation with postoperative dysphagia. Of 9 patients with preoperative dysphagia, 2 (22%) had persistent postoperative dysphagia and 7 had resolution. Of 22 patients without preoperative dysphagia, 3 (14%) developed postoperative dysphagia; for a combined rate of 16%. No patient needed re-intervention beyond early recovery or required reoperation for dysphagia during the follow-up period., Conclusion: In appropriately selected patients, when total fundoplication is performed in the presence of preoperative IEM, the rate of long-term postoperative dysphagia is similar to the reported rate of dysphagia without IEM. With appropriate patient selection, total fundoplication may be performed in patients with IEM without a disproportionate increase in postoperative dysphagia. The presence of preoperative IEM should not be rigidly applied as a contraindication to a total fundoplication.

Inborn errors of metabolism (IEM), otherwise known as inherited metabolic disorders (IMD), are individually rare, but collectively common. IEM pose a challenge to diagnosis, as neonates present with nonspecific signs. A high index of suspicion is essential. Knowledge on clinical presentation may be life saving, especially for conditions that are treatable. It is important for the first-line physicians not to miss treatable disorders. Simplified classification and algorithmic approach help in the clinical setting. This article describes the classification of IEM into three groups, namely group 1 - intoxication disorders, group 2 - energy defects, and group 3 - storage disorders. Clinical presentations of IEM in the neonatal period, a quick guide to the diagnosis with the help of baseline investigations (glucose, arterial blood gas, lactate, ammonia, and ketone abbreviated as GALAK), a tabulated guide to the diagnosis with the help of tandem mass spectrometry (TMS), and gas chromatography and mass spectrometry (GCMS) are summarized in this article. Four principles of therapy that include substrate reduction, provision of deficient metabolites, disposal of toxic metabolites, and increase in enzyme activity are elaborated with particular stress to the diet management. In addition, a list of medications used in the treatment of different disorders classified according to Society for the Study of IEM (SSIEM) is presented.

Adenylosuccinate lyase deficiency is a rare inherited disorder of purine metabolism causing severe neurological impairment ranging from early-onset neonatal epileptic encephalopathy to progressive psychomotor retardation and autism in later life. Diagnostic workup involves the measurement of toxic succinyl purines in body fluids and gene sequencing. The authors describe a 13-mo-old girl with compound heterozygous variants in the ADSL gene, presenting as early-onset seizures, severe neurological impairment, development delay, and hypotonia. Neuroimaging revealed cerebral atrophy, delayed myelination and diffusion restriction in bilateral basal ganglia, thalamus and periventricular white matter. The present case highlights ADSL deficiency as a rare cause of metabolic epilepsy that needs timely recognition and prevention of unnecessary investigations.

Biotin-thiamine-responsive basal ganglia disease is a rare, autosomal recessive, treatable, neurometabolic disorder associated with biallelic pathogenic variations in the SLC19A3 gene. The condition may present as an early-childhood encephalopathy, an early-infantile lethal encephalopathy with lactic acidosis, with or without infantile spasms, or a late-onset Wernicke-like encephalopathy. The key radiological features are bilateral, symmetrical lesions in the caudate, putamen, and medial thalamus, with variable extension into the brain stem, cerebral cortex, and cerebellum. Treatment is life long and includes initiation of high dose biotin and thiamine. Genetic testing confirms the diagnosis. The prognosis depends on the time from diagnosis to the time of vitamin supplementation. The genotype-phenotype correlations are not clear yet, but the early infantile phenotype portends a poorer prognosis. We provide a brief overview of the disorder and emphasize the initiation of high-dose biotin and thiamine in infants and children with unexplained encephalopathy and basal ganglia involvement., Competing Interests: There are no conflicts of interest., (Copyright: © 2006 - 2021 Annals of Indian Academy of Neurology.)

Introduction: In the last two decades, the introduction of tandem mass spectrometry in clinical laboratories has enabled simultaneous testing of numerous acylcarnitines and amino acids from dried blood spots for detecting many aminoacidopathies, organic acidurias and fatty acid oxidation disorders. The expanded newborn screening was introduced in Slovenia in September 2018. Seventeen metabolic diseases have been added to the pre-existing screening panel for congenital hypothyroidism and phenylketonuria, and the newborn screening program was substantially reorganized and upgraded., Methods: Tandem mass spectrometry was used for the screening of dried blood spot samples. Next-generation sequencing was introduced for confirmatory testing. Existing heterogeneous hospital information systems were connected to the same laboratory information system to allow barcode identification of samples, creating reports, and providing information necessary for interpreting the results., Results: In t he first y ear of t he expanded newborn screening a total of 15,064 samples w ere screened. Four patients were confirmed positive with additional testing., Conclusions: An expanded newborn screening program was successfully implemented with the first patients diagnosed before severe clinical consequences., Competing Interests: Conflicts of interest The authors declare that no conflicts of interest exist., (© 2020 Barbka Repič Lampret, Žiga Iztok Remec, Ana Drole Torkar, Mojca Žerjav Tanšek, Andraz Šmon, Vanesa Koračin, Vanja Čuk, Daša Perko, Blanka Ulaga, Ana Marija Jelovšek, Maruša Debeljak, Jernej kovač, Tadej Battelino, Urh Grošelj, published by Sciendo.)

Background: Outcomes for severe hyperammonemia treated with renal replacement therapy (RRT) reported in the literature vary widely. This has created differing recommendations regarding when RRT is beneficial for hyperammonemic patients., Methods: To evaluate our institution's experience with RRT in pediatric patients with inborn errors of metabolism (IEMs) and potential prognostic indicators of a better or worse outcome, we performed a retrospective chart review of patients who received RRT for hyperammonemia. Our cohort included 19 patients with confirmed IEMs who received RRT between 2000 and 2017. Descriptive statistics are presented as medians with interquartile ranges with appropriate statistical testing assuming unequal variance., Results: There were 16 males (84%) and 3 females (16%) identified for inclusion in this study. There were 9 survivors (47%) and 10 non-survivors (53%). The average age of survivors was 67 months (age range from 3 days to 15.6 years). The average age of non-survivors was 1.8 months (age range from 2 days to 18.7 months). Peak ammonia, ammonia on admission, and at RRT initiation were higher in non-survivors compared with survivors. Higher ammonia levels and no change in ammonia between admission and RRT initiation were associated with an increased risk of mortality., Conclusions: Hyperammonemia affects two distinct patient populations; neonates with markedly elevated ammonia levels on presentation and older children who often have established IEM diagnoses and require RRT after failing nitrogen-scavenging therapy. Our experience demonstrates no significant change in mortality associated with neonatal hyperammonemia, which remains high despite improvements in RRT and intensive care.

Untargeted metabolomics may become a standard approach to address diagnostic requests, but, at present, data interpretation is very labor-intensive. To facilitate its implementation in metabolic diagnostic screening, we developed a method for automated data interpretation that preselects the most likely inborn errors of metabolism (IEM). The input parameters of the knowledge-based algorithm were (1) weight scores assigned to 268 unique metabolites for 119 different IEM based on literature and expert opinion, and (2) metabolite Z-scores and ranks based on direct-infusion high resolution mass spectrometry. The output was a ranked list of differential diagnoses (DD) per sample. The algorithm was first optimized using a training set of 110 dried blood spots (DBS) comprising 23 different IEM and 86 plasma samples comprising 21 different IEM. Further optimization was performed using a set of 96 DBS consisting of 53 different IEM. The diagnostic value was validated in a set of 115 plasma samples, which included 58 different IEM and resulted in the correct diagnosis being included in the DD of 72% of the samples, comprising 44 different IEM. The median length of the DD was 10 IEM, and the correct diagnosis ranked first in 37% of the samples. Here, we demonstrate the accuracy of the diagnostic algorithm in preselecting the most likely IEM, based on the untargeted metabolomics of a single sample. We show, as a proof of principle, that automated data interpretation has the potential to facilitate the implementation of untargeted metabolomics for metabolic diagnostic screening, and we provide suggestions for further optimization of the algorithm to improve diagnostic accuracy.

Classic galactosemia (CG) is a potentially lethal inborn error of galactose metabolism that results from deleterious mutations in the human galactose-1 phosphate uridylyltransferase (GALT) gene. Previously, we constructed a GalT -/- (GalT-deficient) mouse model that exhibits galactose sensitivity in the newborn mutant pups, reduced fertility in adult females, impaired motor functions, and growth restriction in both sexes. In this study, we tested whether restoration of hepatic GALT activity alone could decrease galactose-1 phosphate (gal-1P) and plasma galactose in the mouse model. The administration of different doses of mouse GalT (mGalT) mRNA resulted in a dose-dependent increase in mGalT protein expression and enzyme activity in the liver of GalT-deficient mice. Single intravenous (i.v.) dose of human GALT (hGALT) mRNA decreased gal-1P in mutant mouse liver and red blood cells (RBCs) within 24 h with low levels maintained for over a week. Repeated i.v. injections increased hepatic GalT expression, nearly normalized gal-1P levels in liver, and decreased gal-1P levels in RBCs and peripheral tissues throughout all doses. Moreover, repeated dosing reduced plasma galactose by 60% or more throughout all four doses. Additionally, a single intraperitoneal dose of hGALT mRNA overcame the galactose sensitivity and promoted the growth in a GalT -/- newborn pup., (Copyright © 2019 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Routine diagnostic screening of inborn errors of metabolism (IEM) is currently performed by different targeted analyses of known biomarkers. This approach is time-consuming, targets a limited number of biomarkers and will not identify new biomarkers. Untargeted metabolomics generates a global metabolic phenotype and has the potential to overcome these issues. We describe a novel, single platform, untargeted metabolomics method for screening IEM, combining semi-automatic sample preparation with pentafluorophenylpropyl phase (PFPP)-based UHPLC- Orbitrap-MS. We evaluated analytical performance and diagnostic capability of the method by analysing plasma samples of 260 controls and 53 patients with 33 distinct IEM. Analytical reproducibility was excellent, with peak area variation coefficients below 20% for the majority of the metabolites. We illustrate that PFPP-based chromatography enhances identification of isomeric compounds. Ranked z-score plots of metabolites annotated in IEM samples were reviewed by two laboratory specialists experienced in biochemical genetics, resulting in the correct diagnosis in 90% of cases. Thus, our untargeted metabolomics platform is robust and differentiates metabolite patterns of different IEMs from those of controls. We envision that the current approach to diagnose IEM, using numerous tests, will eventually be replaced by untargeted metabolomics methods, which also have the potential to discover novel biomarkers and assist in interpretation of genetic data.

Introduction: Ineffective esophageal motility (IEM) is the most commonly diagnosed abnormality on high-resolution manometry (HRM). However, the clinical significance of IEM and associated reflux burden remains unclear., Aim: Our primary aim was to compare reflux patterns between IEM versus normal motility on HRM., Methods: HRM and reflux studies in patients with IEM and normal motility were retrospectively reviewed. Esophageal pressure topography parameters, reflux variables, and patient-reported outcome questionnaires were explored., Results: A total of 239 patients with IEM were explored. Of these, 146 underwent reflux monitoring. Additionally, 100 patients with normal HRM all of whom had undergone reflux monitoring were included. IEM patients were more likely to have an abnormal number of reflux events compared to normal (22.7% vs. 9.0%, p < 0.01). Including only off-proton pump inhibitor (PPI) testing, IEM patients had higher mean total acid exposure time (AET) and total reflux events compared to normal motility (p = 0.02). Within IEM patients, higher AET modestly correlated with increased percentage of impaired swallows. Increased reflux events modestly correlated with higher impaired swallows and decreased lower esophageal sphincter (LES) resting pressure. Reflux burden increased with higher esophagogastric junction (EGJ) subtype, driven mostly by subtype III, although there was no difference in the distribution of EGJ subtypes between the IEM and normal HRM cohorts., Conclusions: Patients with HRM diagnosis of IEM may be more prone to acid reflux while off-PPI and non-acid reflux while on-PPI. Reflux burden appears to be worse in IEM patients who have lower resting LES pressure, higher EGJ subtype, or higher percentage of impaired swallows.

Background: For inborn errors of metabolism (IEM), metabolomics is performed for three main purposes: 1) development of next generation metabolic screening platforms, 2) identification of new biomarkers in predefined patient cohorts and 3) for identification of new IEM. To date, plasma, urine and dried blood spots are used. We anticipate that cerebrospinal fluid (CSF) holds additional - valuable - information, especially for IEM with neurological involvement. To expand metabolomics to CSF, we here tested whether direct-infusion high-resolution mass spectrometry (DI-HRMS) based non-quantitative metabolomics could correctly capture the biochemical profile of patients with an IEM in CSF., Methods: Eleven patient samples, harboring eight different IEM, and thirty control samples were analyzed using DI-HRMS. First we assessed whether the biochemical profile of the control samples represented the expected profile in CSF. Next, each patient sample was assigned a 'most probable diagnosis' by an investigator blinded for the known diagnoses of the patients., Results: the biochemical profile identified using DI-HRMS in CSF samples resembled the known profile, with - among others - the highest median intensities for mass peaks annotated with glucose, lactic acid, citric acid and glutamine. Subsequent analysis of patient CSF profiles resulted in correct 'most probable diagnoses' for all eleven patients, including non-ketotic hyperglycinaemia, propionic aciduria, purine nucleoside phosphorylase deficiency, argininosuccinic aciduria, tyrosinaemia type I, hyperphenylalaninemia and hypermethioninaemia., Conclusion: We here demonstrate that DI-HRMS based non-quantitative metabolomics accurately captures the biochemical profile of this set of patients in CSF, opening new ways for using metabolomics in CSF in the metabolic diagnostic laboratory., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

In metabolic diagnostics, there is an emerging need for a comprehensive test to acquire a complete view of metabolite status. Here, we describe a non-quantitative direct-infusion high-resolution mass spectrometry (DI-HRMS) based metabolomics method and evaluate the method for both dried blood spots (DBS) and plasma. 110 DBS of 42 patients harboring 23 different inborn errors of metabolism (IEM) and 86 plasma samples of 38 patients harboring 21 different IEM were analyzed using DI-HRMS. A peak calling pipeline developed in R programming language provided Z-scores for ~1875 mass peaks corresponding to ~3835 metabolite annotations (including isomers) per sample. Based on metabolite Z-scores, patients were assigned a 'most probable diagnosis' by an investigator blinded for the known diagnoses of the patients. Based on DBS sample analysis, 37/42 of the patients, corresponding to 22/23 IEM, could be correctly assigned a 'most probable diagnosis'. Plasma sample analysis, resulted in a correct 'most probable diagnosis' in 32/38 of the patients, corresponding to 19/21 IEM. The added clinical value of the method was illustrated by a case wherein DI-HRMS metabolomics aided interpretation of a variant of unknown significance (VUS) identified by whole-exome sequencing. In summary, non-quantitative DI-HRMS metabolomics in DBS and plasma is a very consistent, high-throughput and nonselective method for investigating the metabolome in genetic disease.

Global developmental delay (GDD) and intellectual disability (ID) are common concerns in the paediatric setting. Etiologies of both conditions are highly heterogeneous. The American Academy of Pediatrics, the American Academy of Neurology and the British Columbia-based Treatable Intellectual Disability Endeavor (TIDE) protocol have each proposed multitiered investigations of GDD/ID to guide physicians toward an understanding of etiology that optimizes therapeutic yield. This statement provides a framework for the clinical investigation of GDD/ID in children, along with an updated protocol for Canadian physicians to follow in the etiological investigation of GDD/ID. The revised protocol is based on current knowledge and existing guidelines. Key elements of investigation include formal vision and hearing testing, chromosomal microarray, Fragile-X DNA testing and first-tier testing for treatable inborn errors of metabolism. Brain imaging is recommended in the presence of specific neurological findings.

We study systematically the charging and release mechanisms of a flexible macromolecule, modeled by poly(ethylene glycol) (PEG), in a droplet by using molecular dynamics simulations. We compare how PEG is solvated and charged by sodium Na + ions in a droplet of water (H 2 O), acetonitrile (MeCN), and their mixtures. Initially, we examine the location and the conformation of the macromolecule in a droplet bearing no net charge. It is revealed that the presence of charge carriers do not affect the location of PEG in aqueous and MeCN droplets compared with that in the neutral droplets, but the location of the macromolecule and the droplet size do affect the PEG conformation. PEG is charged on the surface of a sodiated aqueous droplet that is found close to the Rayleigh limit. Its charging is coupled to the extrusion mechanism, where PEG segments leave the droplet once they coordinate a Na + ion or in a correlated motion with Na + ions. In contrast, as PEG resides in the interior of a MeCN droplet, it is sodiated inside the droplet. The compact macro-ion transitions through partially unwound states to an extended conformation, a process occurring during the final stage of desolvation and in the presence of only a handful of MeCN molecules. For charged H 2 O/MeCN droplets, the sodiation of PEG is determined by the H 2 O component, reflecting its slower evaporation and preference over MeCN for solvating Na + ions. We use the simulation data to construct an analytical model that suggests that the droplet surface electric field may play a role in the macro-ion-droplet interactions that lead to the extrusion of the macro-ion. This study provides the first evidence of the effect of the surface electric field by using atomistic simulations. Graphical Abstract ᅟ.

As a common feature of eukaryotic proteins, tandem amino acid repeat has been studied extensively in both animal and plant proteins. Here, a comparative analysis focusing on the proteins having tandem repeats was conducted in eight microsporidia, including four mammal-infecting microsporidia (Encephalitozoon cuniculi, Encephalitozoon intestinalis, Encephalitozoon hellem and Encephalitozoon bieneusi) and four insect-infecting microsporidia (Nosema apis, Nosema ceranae, Vavraia culicis and Nosema bombycis). We found that the proteins with tandem repeats were abundant in these species. The quantity of these proteins in insect-infecting microsporidia was larger than that of mammal-infecting microsporidia. Additionally, the hydrophilic residues were overrepresented in the tandem repeats of these eight microsporidian proteins and the amino acids residues in these tandem repeat sequences tend to be encoded by GC-rich codons. The tandem repeat position within proteins of insect-infecting microsporidia was randomly distributed, whereas the tandem repeats within proteins of mammal-infecting microsporidia rarely tend to be present in the N terminal regions, when compared with those present in the C terminal and middle regions. Finally, a hypothetical protein EOB14572 possessing four tandem repeats was successfully characterized as a novel endospore wall protein, which colocalized with polar tube of N. bombycis. Our study provided useful insight for the study of the proteins with tandem repeats in N. bombycis, but also further enriched the spore wall components of this obligate unicellular eukaryotic parasite., (© 2017 The Author(s) Journal of Eukaryotic Microbiology © 2017 International Society of Protistologists.)

Inborn errors of metabolism (IEMs) are individually rare but collectively common. As more and more genes are cloned and specific disease-causing mutations are identified, the diagnosis of IEMs is becoming increasingly confirmed by mutation analysis. Diagnosis is important not only for treatment and prognosis but also for genetic counselling and prenatal diagnosis in subsequent pregnancies. A wide range of molecular methods is available for the identification of mutations and other DNA variants, most of which are based on the Polymerase Chain Reaction (PCR). In this chapter, we focus on PCR-based methods for the detection of point mutations or small deletions/insertions as these are the most frequent causes of IEMs.

Mucin-1 (MUC1) affects cancer progression in lung adenocarcinoma, and its aberrant expression pattern has been correlated with poor tumor differentiation and impaired prognosis. In this study, the immunohistochemical expression of MUC1 and Mucin-4 (MUC4) was analyzed in a series of 106 surgically operated stage I-IV pulmonary adenocarcinomas. MUC1 immunohistochemistry was evaluated according to the Nagai classification, and the immunohistochemical profile of the tumors was correlated with detailed clinical and histological data. The effect of cigarette smoke on MUC1 expression in lung cancer cell lines was examined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunoelectron microscopy (IEM). In contrast to the normal apical localization of MUC1, a basolateral and cytoplasmic (depolarized) MUC1 expression pattern was frequently encountered in the high-grade subtypes, i.e., solid predominant adenocarcinoma and the cribriform variant of acinar predominant adenocarcinoma (p < 0.001), and was rarely observed in tumors containing a non-predominant lepidic component (p < 0.001). Furthermore, the altered staining pattern of MUC1 correlated with stage (p = 0.002), reduced overall survival (p = 0.031), and was associated with smoking (p < 0.001). When H1650 adenocarcinoma cells were exposed to cigarette smoke and analyzed by RT-qPCR and IEM, the levels of the MUC1 transcript and protein were elevated (p = 0.042). In conclusion, MUC1 participates in the pathogenesis of lung adenocarcinoma and associates with smoking both in vitro and in vivo. In lung adenocarcinoma, depolarized MUC1 protein expression correlated with histological growth patterns, stage, and patient outcome.

Cerebrotendinous Xanthomatosis (CTX) is a treatable inborn error of metabolism caused by recessive variants in CYP27A1. Clinical presentation varies, but typically includes infant-onset chronic diarrhea, juvenile-onset bilateral cataracts, and later-onset tendinous xanthomas and progressive neurological dysfunction. CYP27A1 plays an essential role in side-chain oxidation of cholesterol necessary for the synthesis of the bile acid, chenodeoxycholic acid, and perturbations in this gene that reduce enzyme activity result in elevations of cholestanol. It is commonly held that CTX is exceedingly rare, but epidemiological studies are lacking. In order to provide an accurate incidence estimate of CTX, we studied the ExAC cohort of ~60,000 unrelated adults from global populations to determine the allele frequency of the 57 variants in CYP27A1 reported pathogenic for CTX. In addition, we conducted bioinformatics analyses on these CTX-causing variants and determined a bioinformatics profile to predict variants that may be pathogenic but have not yet been reported in the CTX patient literature. An additional 29 variants were identified that met bioinformatics criteria for being potentially pathogenic. Incidence was estimated based allele frequencies of pathogenic CTX variants plus those determined to be potentially pathogenic. One variant, p.P384L, previously reported in three unrelated CTX families had an allele frequency ≥ 1% in European, Latino and Asian populations. Three additional mutations had a frequency of ≥ 0.1% in Asian populations. CTX disease incidence was calculated excluding the high frequency p.P384L and separately using a genetic paradigm where this high frequency variant only causes classic CTX when paired in trans with a null variant. These calculations place CTX incidence ranging from 1:134,970 to 1:461,358 in Europeans, 1:263,222 to 1:468,624 in Africans, 1:71,677 to 1:148,914 in Americans, 1:64,267 to 1:64,712 in East Asians and 1:36,072 to 1:75,601 in South Asians. This work indicates CTX is under-diagnosed and improved patient screening is needed as early intervention prevents disease progression., (Copyright © 2015. Published by Elsevier Inc.)

Background: In 2012, the first Nigerian Hepatitis B Virus (HBV) immune escape mutant (IEM) case was detected in a pregnant woman in southwestern Nigeria. Consequently, this study was designed to investigate the presence and possible circulation of IEMs amongst asymptomatic community dwellers in southwestern Nigeria., Methods: Blood specimens collected from 438 asymptomatic community dwellers were screened for HBsAg using ELISA technique. Subsequently, the S-gene was amplified in HBsAg positive samples by a nested PCR protocol, and amplicons sequenced. Isolates were then subtyped by amino acid residues at positions 122, 127, 134 and 160, and genotyped by phylogenetic analysis., Results: Of the 31 (7.08%) samples positive for HBsAg, the ∼ 408 bp Sgene fragment was successfully amplified and sequenced in 27. Samples obtained from 4 patients could not be amplified due to low titres. Sequence data from only 15 of the isolates could be analysed further as eight of the remaining 12 had multiple peaks while the rest three showed no similarity to any HBV gene when subjected to BLAST analysis. Thirteen of the 15 isolates were identified as genotype E. Eleven of which were subtyped as ayw4 while the remaining two could not be subtyped due to sR122Q/P substitutions. The last two isolates that could not be genotyped and subtyped had other mutations in the "a" determinant associated with IEMs., Conclusions: This study confirmed presence and circulation of HBV IEM in Nigeria, the country's inclusion in the genotype E crescent, and the value of phylogenetic analysis in HBV identification., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Flaxseed protein hydrolysate has been fractionated by electrodialysis with two ultrafiltration membranes (20 and 50 kDa) stacked in the system for the recovery of two specific cationic peptide fractions (KCl-F1 and KCl-F2). After 360 min of treatment, peptide migration increased as a function of time in KCl compartments. Moreover, the use of two different ultrafiltration membrane allowed concentration of the 300-400 and 400-500 Da molecular weight range peptides in the KCl-F1 and KCl-F2 fractions, respectively, compared to the initial hydrolysate. After mass spectrometry analysis, higher amounts of low molecular weight peptides were recovered in the KCl-F2 compartment while relatively higher molecular weight peptides were more detected in the KCl-F1 compartment. Amino acid analysis showed that His, Lys and Arg were especially concentrated in the KCl compartments. Finally, glucose-transport assay demonstrated that the KCl-F2 fraction increased glucose uptake while oral administration of KCl-F1 and final FPH decreased systolic blood pressure., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Diagnosis of aminoacidopathies and organic acidemias constitutes a real challenge in a developing country with high consanguinity rate and no systematic newborn screening. We report a twelve-year experience with the identification of these disorders in Lebanon, based on their clinical and biochemical profiles., Methods: In this retrospective study, we reviewed clinical presentation and biochemical investigations of 294 patients. Traditional chromatographic methods were used for analyses. Findings were linked to the identified disorders., Results: Out of 2921 patients, presenting to our metabolic program with neurological, digestive, family history and/or other symptoms suggestive of aminoacidopathy or organic acidemia, 294 patients were included with confirmed amino or organic acid disorder. The overall analytical yield was 10%. Aminoacidopathies were three-fold higher than organic acidemias. Phenylketonuria and methylmalonic acidemia were the most frequent. The majority of patients (79%) were symptomatic (median age: 14months, range: 1day-44years), mainly with neurological manifestations (87%). Intellectual disability was mostly due to phenylketonuria (73%). Chronic liver failure was frequent in maple syrup urine disease (53%). Plasma amino and urine organic acid chromatography were diagnostic in 8.8% and 3.9% of analyzed cases, respectively. Change in chromatographic technique from reversed-phase to ion-exchange enhanced the detection of many aminoacidopathies., Conclusions: In the absence of newborn screening, the majority of aminoacidopathy and organic acidemia cases are still diagnosed clinically. This study emphasizes the importance of clinical awareness and accurate biochemical analyses as key tools for diagnosis in countries like ours, and the necessity for a comprehensive national newborn screening program., (© 2013.)

Primary Hyperoxaluria Type I (PH1) is a severe rare disorder of metabolism due to inherited mutations on liver peroxisomal alanine:glyoxylate aminotransferase (AGT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme whose deficiency causes the deposition of calcium oxalate crystals in the kidneys and urinary tract. PH1 is an extremely heterogeneous disease and there are more than 150 disease-causing mutations currently known, most of which are missense mutations. Moreover, the molecular mechanisms by which missense mutations lead to AGT deficiency span from structural, functional to subcellular localization defects. Gly161 is a highly conserved residue whose mutation to Arg, Cys or Ser is associated with PH1. Here we investigated the molecular bases of the AGT deficit caused by Gly161 mutations with expression studies in a mammalian cellular system paired with biochemical analyses on the purified recombinant proteins. Our results show that the mutations of Gly161 (i) strongly reduce the expression levels and the intracellular half-life of AGT, and (ii) make the protein in the apo-form prone to an electrostatically-driven aggregation in the cell cytosol. The coenzyme PLP, by shifting the equilibrium from the apo- to the holo-form, is able to reduce the aggregation propensity of the variants, thus partly decreasing the effect of the mutations. Altogether, these results shed light on the mechanistic details underlying the pathogenicity of Gly161 variants, thus expanding our knowledge of the enzymatic phenotypes leading to AGT deficiency., (© 2013.)

The methylmalonic acidemia is an inborn error of metabolism (IEM) characterized by methylmalonic acid (MMA) accumulation in body fluids and tissues, causing neurological dysfunction, mitochondrial failure and oxidative stress. Although neurological evidence demonstrate that infection and/or inflammation mediators facilitate metabolic crises in patients, the involvement of neuroinflammatory processes in the neuropathology of this organic acidemia is not yet established. In this experimental study, we used newborn Wistar rats to induce a model of chronic acidemia via subcutaneous injections of methylmalonate (MMA, from 5th to 28th day of life, twice a day, ranged from 0.72 to 1.67 μmol/g as a function of animal age). In the following days (29th-31st) animal behavior was assessed in the object exploration test and elevated plus maze. It was performed differential cell and the number of neutrophils counting and interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels in the blood, as well as levels of IL-1β, TNF-α, inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine (3-NT) in the cerebral cortex were measured. Behavioral tests showed that animals injected chronically with MMA have a reduction in the recognition index (R.I.) when the objects were arranged in a new configuration space, but do not exhibit anxiety-like behaviors. The blood of MMA-treated animals showed a decrease in the number of polymorphonuclear and neutrophils, and an increase in mononuclear and other cell types, as well as an increase of IL-1β and TNF-α levels. Concomitantly, MMA increased levels of IL-1β, TNF-α, and expression of iNOS and 3-NT in the cerebral cortex of rats. The overall results indicate that chronic administration of MMA increased pro-inflammatory markers in the cerebral cortex, reduced immune system defenses in blood, and coincide with the behavioral changes found in young rats. This leads to speculate that, through mechanisms not yet elucidated, the neuroinflammatory processes during critical periods of development may contribute to the progression of cognitive impairment in patients with methylmalonic acidemia., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Objective: Prompt ascertainment is crucial for the management of hyperammonemic infants. Because these patients are rare and recognition of hyperammonemia is often delayed, we designed and implemented an electronic medical record (EMR)-based tool to assist physicians in the detection of hyperammonemia., Methods: We retrospectively evaluated the hospitalizations of prior hyperammonemic infants to identify codable elements that could trigger an EMR-based warning. An alert was designed and implemented and its utilization was prospectively analyzed., Results: Blood gas studies were obtained universally and early in the retrospectively evaluated infants (x¯=26h before ammonia level). Prompting physicians to evaluate ammonia after ordering blood gas studies would have accelerated the initial ammonia order in 89% of retrospective cases. The alert has activated 184 times over the first six months of operation leading to 63 laboratory evaluations and detection of one hyperammonemic infant., Conclusion: Implementation of an EMR-based warning system can improve surveillance for hyperammonemia in a susceptible population., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Unlabelled: Quantification of acylcarnitines is used for screening and diagnosis of inborn error of metabolism (IEM). While newborn screening is performed in dried blood spots (DBSs), general metabolic investigation is often performed in plasma. Information on the correlation between plasma and DBS acylcarnitine profiles is scarce. In this study, we directly compared acylcarnitine concentrations measured in DBS with those in the corresponding plasma sample. Additionally, we tested whether ratios of acylcarnitines in both matrices are helpful for diagnostic purpose when primary markers fail., Study Design: DBS and plasma were obtained from controls and patients with a known IEM. (Acyl)carnitines were converted to their corresponding butyl esters and analyzed using HPLC/MS/MS., Results: Free carnitine concentrations were 36% higher in plasma compared to DBS. In contrast, in patients with carnitine palmitoyltransferase 1 (CPT-1) deficiency free carnitine concentration in DBS was 4 times the concentration measured in plasma. In carnitine palmitoyltransferase 2 (CPT-2) deficiency, primary diagnostic markers were abnormal in plasma but could also be normal in DBS. The calculated ratios for CPT-1 (C0/(C16+C18)) and CPT-2 ((C16+C18:1)/C2) revealed abnormal values in plasma. However, normal ratios were found in DBS of two (out of five) samples obtained from patients diagnosed with CPT-2., Conclusions: Relying on primary acylcarnitine markers, CPT-1 deficiency can be missed when analysis is performed in plasma, whereas CPT-2 deficiency can be missed when analysis is performed in DBS. Ratios of the primary markers to other acylcarnitines restore diagnostic recognition completely for CPT-1 and CPT-2 in plasma, while CPT-2 can still be missed in DBS., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A trans-National Institutes of Health initiative, Nutrition and Dietary Supplement Interventions for Inborn Errors of Metabolism (NDSI-IEM), was launched in 2010 to identify gaps in knowledge regarding the safety and utility of nutritional interventions for the management of inborn errors of metabolism (IEM) that need to be filled with evidence-based research. IEM include inherited biochemical disorders in which specific enzyme defects interfere with the normal metabolism of exogenous (dietary) or endogenous protein, carbohydrate, or fat. For some of these IEM, effective management depends primarily on nutritional interventions. Further research is needed to demonstrate the impact of nutritional interventions on individual health outcomes and on the psychosocial issues identified by patients and their families. A series of meetings and discussions were convened to explore the current United States' funding and regulatory infrastructure and the challenges to the conduct of research for nutritional interventions for the management of IEM. Although the research and regulatory infrastructure are well-established, a collaborative pathway that includes the professional and advocacy rare disease community and federal regulatory and research agencies will be needed to overcome current barriers., (Copyright © 2013. Published by Elsevier Inc. All rights reserved.)

Background: The treatment of inborn errors of metabolism (IEM) has seen significant advances over the last decade. Many medicines have been developed and the survival rates of some patients with IEM have improved. Dosages of drugs used for the treatment of various IEM can be obtained from a range of sources but tend to vary among these sources. Moreover, the published dosages are not usually supported by the level of existing evidence, and they are commonly based on personal experience., Methods: A literature search was conducted to identify key material published in English in relation to the dosages of medicines used for specific IEM. Textbooks, peer reviewed articles, papers and other journal items were identified. The PubMed and Embase databases were searched for material published since 1947 and 1974, respectively. The medications found and their respective dosages were graded according to their level of evidence, using the grading system of the Oxford Centre for Evidence-Based Medicine., Results: 83 medicines used in various IEM were identified. The dosages of 17 medications (21%) had grade 1 level of evidence, 61 (74%) had grade 4, two medications were in level 2 and 3 respectively, and three had grade 5., Conclusions: To the best of our knowledge, this is the first review to address this matter and the authors hope that it will serve as a quickly accessible reference for medications used in this important clinical field.

The objective of this paper is to analyze the behaviour of a backscattered signalaccording to soil moisture depth over bare soils. Analysis based on experimental verticalmoisture profiles and ASAR/ENVISAT measurements has been carried out. A modifiedIEM model with three permittivity layers (0-1cm, 1-2cm, 2-5cm) has been developed andused in this study. Results show a small effect of moisture profile on the backscatteredsignal (less than 0.5dB). However, measurements and simulations have provided a moredetailed insight into the behaviour of the radar signal and have shown that it was importantto consistently use the same protocol when performing ground truth measurements of soilmoisture.