An evaluation of untargeted metabolomics methods to characterize inborn errors of metabolism.

Inborn errors of metabolism (IEMs) encompass a diverse group of disorders that can be difficult to classify due to heterogenous clinical, molecular, and biochemical manifestations. Untargeted metabolomics platforms have become a popular approach to analyze IEM patient samples because of their ability to detect many metabolites at once, accelerating discovery of novel biomarkers, and metabolic mechanisms of disease. However, there are concerns about the reproducibility of untargeted metabolomics research due to the absence of uniform reporting practices, data analyses, and experimental design guidelines. Therefore, we critically evaluated published untargeted metabolomic platforms used to characterize IEMs to summarize the strengths and areas for improvement of this technology as it progresses towards the clinical laboratory. A total of 96 distinct IEMs were collectively evaluated by the included studies. However, most of these IEMs were evaluated by a single untargeted metabolomic method, in a single study, with a limited cohort size (55/96, 57%). The goals of the included studies generally fell into two, often overlapping, categories: detecting known biomarkers from many biochemically distinct IEMs using a single platform, and detecting novel metabolites or metabolic pathways. There was notable diversity in the design of the untargeted metabolomic platforms. Importantly, the majority of studies reported adherence to quality metrics, including the use of quality control samples and internal standards in their experiments, as well as confirmation of at least some of their feature annotations with commercial reference standards. Future applications of untargeted metabolomics platforms to the study of IEMs should move beyond single-subject analyses, and evaluate reproducibility using a prospective, or validation cohort.

The Mendelian disorders of chromatin machinery: Harnessing metabolic pathways and therapies for treatment.

The Mendelian disorders of chromatin machinery (MDCMs) represent a distinct subgroup of disorders that present with neurodevelopmental disability. The chromatin machinery regulates gene expression by a range of mechanisms, including by post-translational modification of histones, responding to histone marks, and remodelling nucleosomes. Some of the MDCMs that impact on histone modification may have potential therapeutic interventions. Two potential treatment strategies are to enhance the intracellular pool of metabolites that can act as substrates for histone modifiers and the use of medications that may inhibit or promote the modification of histone residues to influence gene expression. In this article we discuss the influence and potential treatments of histone modifications involving histone acetylation and histone methylation. Genomic technologies are facilitating earlier diagnosis of many Mendelian disorders, providing potential opportunities for early treatment from infancy. This has parallels with how inborn errors of metabolism have been afforded early treatment with newborn screening. Before this promise can be fulfilled, we require greater understanding of the biochemical fingerprint of these conditions, which may provide opportunities to supplement metabolites that can act as substrates for chromatin modifying enzymes. Importantly, understanding the metabolomic profile of affected individuals may also provide disorder-specific biomarkers that will be critical for demonstrating efficacy of treatment, as treatment response may not be able to be accurately assessed by clinical measures.

Inborn errors of the malate aspartate shuttle - Update on patients and cellular models.

The malate aspartate shuttle (MAS) plays a pivotal role in transporting cytosolic reducing equivalents - electrons - into the mitochondria for energy conversion at the electron transport chain (ETC) and in the process of oxidative phosphorylation. The MAS consists of two pairs of cytosolic and mitochondrial isoenzymes (malate dehydrogenases 1 and 2; and glutamate oxaloacetate transaminases 1 and 2) and two transporters (malate-2-oxoglutarate carrier and aspartate glutamate carrier (AGC), the latter of which has two tissue-dependent isoforms AGC1 and AGC2). While the inner mitochondrial membrane is impermeable to NADH, the MAS forms one of the main routes for mitochondrial electron uptake by promoting uptake of malate. Inherited bi-allelic pathogenic variants in five of the seven components of the MAS have been described hitherto and cause a wide spectrum of symptoms including early-onset epileptic encephalopathy. This review provides an overview of reported patients suffering from MAS deficiencies. In addition, we give an overview of diagnostic procedures and research performed on patient-derived cellular models and tissues. Current cellular models are briefly discussed and novel ways to achieve a better understanding of MAS deficiencies are highlighted.

Genetic aetiologies of acute liver failure.

Acute liver failure (ALF) is a rare, rapidly evolving, clinical syndrome with devastating consequences where definitive treatment is by emergency liver transplantation. Establishing a diagnosis can be challenging and, historically, the cause of ALF was unidentified in up to half of children. However, recent technological and clinical advances in genomic medicine have led to an increasing proportion being diagnosed with monogenic aetiologies of ALF. The conditions encountered include a diverse group of inherited metabolic disorders each with prognostic and treatment implications. Often these disorders are clinically indistinguishable and may even mimic disorders of immune regulation or red cell disorders. Rapid genomic sequencing for children with ALF is, therefore, a key component in the diagnostic work up today. This review focuses on the monogenic aetiologies of ALF.

Living with trimethylaminuria and body and breath malodour: personal perspectives.

BACKGROUND: Many people suffer from body and breath malodour syndromes. One of these is trimethylaminuria, a condition characterized by excretion in breath and bodily fluids of trimethylamine, a volatile and odorous chemical that has the smell of rotting fish. Trimethylaminuria can be primary, due to mutations in the gene encoding flavin-containing monooxygenase 3, or secondary, due to various causes. To gain a better understanding of problems faced by United Kingdom residents affected by body and breath malodour conditions, we conducted a survey. METHODS: Two anonymous online surveys, one for adults and one for parents/guardians of affected children, were conducted using the Opinio platform. Participants were invited via a trimethylaminuria advisory website. Questions were a mix of dropdown, checkbox and open-ended responses. Forty-four adults and three parents/guardians participated. The dropdown and checkbox responses were analysed using the Opinio platform. RESULTS: All participants reported symptoms of body/breath odour. However, not all answered every question. Twenty-three respondents experienced difficulties in being offered a diagnostic test for trimethylaminuria. Problems encountered included lack of awareness of the disorder by medical professionals and reluctance to recognise symptoms. Of those tested, 52% were diagnosed with trimethylaminuria. The main problems associated with living with body/breath malodours were bullying, harassment and ostracism in either the workplace (90%) or in social settings (88%). All respondents thought their condition had disadvantaged them in their daily lives. Open-ended responses included loss of confidence, stress, exclusion, isolation, loneliness, depression and suicidal thoughts. Respondents thought their lives could be improved by greater awareness and understanding of malodour conditions by medical professionals, employers and the general public, and appreciation that the malodour was due to a medical condition and not their fault. CONCLUSIONS: Breath and body malodour conditions can cause immense hardship and distress, both mentally and socially, having devastating effects on quality of life. It would be advantageous to establish a standardised pathway from primary care to a specialist unit with access to a robust and reliable test and diagnostic criteria. There is a need to recognise malodour disorders as a disability, giving affected individuals the same rights as those with currently recognised disabilities.

Congenital chloride diarrhoea in a Chinese infant with a compound heterozygous SLC26A3 mutation.

INTRODUCTION: Congenital chloride diarrhoea (CCD) is an autosomal recessive condition that causes secretory diarrhoea and potentially deadly electrolyte imbalances in infants because of solute carrier family 26 member 3 (SLC26A3) gene mutations. CASE PRESENTATION: A 7-month-old Chinese infant with a history of maternal polyhydramnios presented with frequent watery diarrhoea, severe dehydration, hypokalaemia, hyponatraemia, failure to thrive, metabolic alkalosis, hyperreninaemia, and hyperaldosteronaemia. Genetic testing revealed a compound heterozygous SLC26A3 gene mutation in this patient (c.269_270dup and c.2006 C > A). Therapy was administered in the form of oral sodium and potassium chloride supplements, which decreased stool frequency. CONCLUSIONS: CCD should be considered when an infant presents with prolonged diarrhoea during infancy, particularly in the context of maternal polyhydramnios and dilated foetal bowel loops.

Exploration of clinical and ethical issues in an expanded newborn metabolic screening programme: a qualitative interview study of healthcare professionals in Hong Kong.

INTRODUCTION: The Newborn Screening Programme for Inborn Errors of Metabolism (NBSIEM) enables early intervention and prevents premature mortality. Residual dried bloodspots (rDBS) from the heel prick test are a valuable resource for research. However, there is minimal data regarding how stakeholders in Hong Kong view the retention and secondary use of rDBS. This study aimed to explore views of the NBSIEM and the factors associated with retention and secondary use of rDBS among healthcare professionals in Hong Kong. METHODS: Between August 2021 and January 2022, semi-structured interviews were conducted with 30 healthcare professionals in obstetrics, paediatrics, and chemical pathology. Key themes were identified through thematic analysis, including views towards the current NBSIEM and the retention and secondary use of rDBS. RESULTS: After implementation of the NBSIEM, participants observed fewer patients with acute decompensation due to undiagnosed inborn errors of metabolism. The most frequently cited clinical utilities were early detection and improved health outcomes. Barriers to rDBS storage and its secondary use included uncertain value and benefits, trust concerns, and consent issues. CONCLUSION: This study highlighted healthcare professionals' concerns about the NBSIEM and uncertainties regarding the handling or utilisation of rDBS. Policymakers should consider these concerns when establishing new guidelines.

Identifying Metabolic Diseases That Precipitate Neonatal Seizures.

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

Closing the gap: An urgent need for newborn screening of organic acid disorders in developing countries.

Organic acid disorders are rare inherited metabolic disorders of key metabolic pathways. For the identification of specific organic acids, investigation of urinary metabolites and genetic testing are required through newborn screening programmes. Delayed diagnosis leads to complications, such as cardiac attacks, respiratory problems, neuro-developmental disorders, intellectual disability, and even premature death. The burden of such inherited disorders is quite high in developing countries of South Asia due to high rate of consanguinity in the region. Unfortunately, such disorders are left untreated due to the lack of screening facilities in such countries. The current narrative review was planned to highlight the urgent need for closing this gap and implementing effective newborn screening programmes for organic acid disorders in developing countries. The implementation of effective programmes is crucial for reducing morbidity and mortality, and for improving the quality of life for the affected children and of their families, thus promoting global health equity.

Suspected Pseudocholinesterase Deficiency During Left Thyroid Lobectomy and Isthmusectomy: A Case Report.

BACKGROUND: Pseudocholinesterase (butyrylcholinesterase) deficiency is an acquired or inherited condition in which decreased plasma levels of the pseudocholinesterase enzyme lead to an inability to metabolize the neuromuscular blocking agents succinylcholine and mivacurium, prolonging their paralytic effects. This often results in delayed extubation and additional intensive care requirements in the postoperative period. CASE DESCRIPTION: We describe a case of suspected pseudocholinesterase deficiency in a previously healthy 59-year-old female who underwent a left thyroid lobectomy and isthmusectomy. The patient received 120 mg of succinylcholine chloride before intubation. The patient did not meet extubation criteria following the completion of the procedure approximately two hours after receiving succinylcholine chloride. The patient was transferred to the ICU for respiratory support and for the medication to clear from the patient's system. The patient regained muscle control approximately four hours after receiving succinylcholine chloride and was extubated without complication. The patient shared post-extubation that she had a blood relative with the diagnosis of pseudocholinesterase deficiency. CONCLUSION: Pseudocholinesterase deficiency is rare but can result in potentially serious complications following the administration of succinylcholine chloride, mivacurium, or ester local anesthetics due to reduced metabolism and subsequently increased pharmacodynamic effects. Given the widespread use of succinylcholine chloride as a neuromuscular blocking agent, such as in this case, providers must be aware of the presentation, pathophysiology, diagnosis, and management. Additionally, this case demonstrates the importance of thoroughly inquiring about any personal or family history of anesthetic complications during a preoperative assessment.

Clinical characteristics and genetic analysis of six children with carnitine palmitoyltransferase 2 deficiency. / å ­ä¾‹è‚‰ç¢±æ£•æ¦ˆé °åŸºè½¬ç§»é ¶2ç¼ºä¹ç—‡æ‚£å„¿ä¸´åºŠç‰¹å¾åŠåŸºå› å˜å¼‚åˆ†æž.

OBJECTIVES: To investigate the clinical characteristic and genetic variants of children with carnitine palmitoyltransferase 2 (CPT2) deficiency. METHODS: The clinical and genetic data of 6 children with CPT2 deficiency were retrospectively analyzed. The blood acylcarnitines and genetic variants were detected with tandem mass spectrometry and whole-exon gene sequencing, respectively. RESULTS: There were 4 males and 2 females with a mean age of 32 months (15 d-9 years) at diagnosis. One case was asymptomatic and with normal laboratory test results, 2 had delayed onset, and 3 were of infantile type. Three cases were diagnosed at neonatal screening, and 3 cases presented with clinical manifestations of fever, muscle weakness, and increased muscle enzymes. Five children presented with decreased free carnitine and elevated levels of palmitoyl and octadecenoyl carnitines. CPT2 gene variants were detected at 8 loci in 6 children (4 harboring biallelic mutations and 2 harboring single locus mutations), including 3 known variants (p.R631C, p.T589M, and p.D255G) and 5 newly reported variants (p.F352L, p.R498L, p.F434S, p.A515P, and c.153-2A>G). It was predicted by PolyPhen2 and SIFT software that c.153-2A>G and p.F352L were suspected pathogenic variants, while p.R498L, p.F434S and p.A515P were variants of unknown clinical significance. CONCLUSIONS: The clinical phenotypes of CPT2 deficiency are diverse. An early diagnosis can be facilitated by neonatal blood tandem mass spectrometry screening and genetic testing, and most patients have good prognosis after a timely diagnosis and treatment.

EVALUATION OF SOME LABORATORY PARAMETERS IN PATIENTS WITH MORBID OBESITY AFTER BARIATRIC SURGERY.

Obesity is a global challenge of the 21st century, both in terms of morbidity and mortality worldwide. In this article, we studied the effect of surgical treatment on glycemic indicators within morbid obesity patients, therefore assessing the glucose and glycosylated hemoglobin in blood serum. Also, we evaluated the hormonal background associated with Obesity - by measuring the insulin level in patients. This study included 40 patients who underwent bariatric surgery in the period 2017-2021; the above laboratory parameters were assessed before and after surgery. The control group consisted of 40 patients with morbid Obesity planning bariatric surgery in the future. Thus, we investigated three groups: I - control group - 40 patients with morbid Obesity who planning bariatric surgery in the future, Group II - 40 patients with morbid Obesity immediately before bariatric surgery and group III - the same 40 patients as in the second group, but after bariatric surgery performed between 2017 and 2021. It should be noted that the glucose level is ⁓1.4 times higher in patients immediately before bariatric surgery (group II) compared to the control group (group I) and ⁓1.19 times lower in the postoperative period (group III) according to compared with the control group. The insulin level is ⁓1.4 times higher in patients immediately before bariatric surgery (group II) compared to the control group (p=0.0066) and ⁓2.5 times lower in the postoperative period (group III) compared to the control group (p=0.0001). According to the results, the insulin level after surgery decreases by ⁓3.7 times compared to the preoperative group (p=0.0001). The glycated hemoglobin level in bariatric patients is lower (slightly) than in the control group (⁓1.01 times), which is explained by the preoperative preparation of the patient at least several months before surgery. In postoperative patients, it decreased by ⁓1.06 times compared to preoperative patients. Thus, today, bariatric surgery is undoubtedly a very effective method of radical treatment of morbid Obesity, which we can consider to be one of the most essential parts of the holistic model of obesity treatment.

Inborn errors of metabolism: Historical perspectives to contemporary management.

There are many different genetic diseases called inborn errors of metabolism (IEM) which result from defective enzymes in the metabolic pathway. As a result, these defects either cause a harmful accumulation of substances or lead to a lack of certain types of molecule. The present review traces the origin and development of IEMs from Sir Archibald Garrod's theory in the early 20th century to current diagnostic and therapeutic approaches. It also involves a systematic literature review complying with PRISMA which included studies sourced from PubMed, Scopus, Web of Science and Google Scholar. It points out that high rates of consanguinity are associated with high prevalence rates for IEMs especially in the Eastern Mediterranean area. IEMS are classified as energy deficiency disorders, intoxication disorders, and storage disorders. Each category has a variety of clinical manifestations. This study incorporates different diagnostic methods ranging from simple biochemical tests to tandem mass spectrometry and next generation sequencing; while management approaches such as dietary modifications, enzyme replacement therapy and gene therapy were assessed for their efficacy. Specific attention is paid to Pakistan where there exists considerable consanguinity among people coupled with inadequate health care services which have seriously affected delivery of health care services thereby leading to numerous challenges for the country healthcare system during service provision.

Towards personalized genome-scale modeling of inborn errors of metabolism for systems medicine applications.

Inborn errors of metabolism (IEMs) are a group of more than 1000 inherited diseases that are individually rare but have a cumulative global prevalence of 50 per 100,000 births. Recently, it has been recognized that like common diseases, patients with rare diseases can greatly vary in the manifestation and severity of symptoms. Here, we review omics-driven approaches that enable an integrated, holistic view of metabolic phenotypes in IEM patients. We focus on applications of Constraint-based Reconstruction and Analysis (COBRA), a widely used mechanistic systems biology approach, to model the effects of inherited diseases. Moreover, we review evidence that the gut microbiome is also altered in rare diseases. Finally, we outline an approach using personalized metabolic models of IEM patients for the prediction of biomarkers and tailored therapeutic or dietary interventions. Such applications could pave the way towards personalized medicine not just for common, but also for rare diseases.

Functional overlap of inborn errors of immunity and metabolism genes defines T cell metabolic vulnerabilities.

Inborn errors of metabolism (IEMs) and immunity (IEIs) are Mendelian diseases in which complex phenotypes and patient rarity have limited clinical understanding. Whereas few genes have been annotated as contributing to both IEMs and IEIs, immunometabolic demands suggested greater functional overlap. Here, CRISPR screens tested IEM genes for immunologic roles and IEI genes for metabolic effects and found considerable previously unappreciated crossover. Analysis of IEMs showed that N-linked glycosylation and the hexosamine pathway enzyme Gfpt1 are critical for T cell expansion and function. Further, T helper (TH1) cells synthesized uridine diphosphate N-acetylglucosamine more rapidly and were more impaired by Gfpt1 deficiency than TH17 cells. Screening IEI genes found that Bcl11b promotes the CD4 T cell mitochondrial activity and Mcl1 expression necessary to prevent metabolic stress. Thus, a high degree of functional overlap exists between IEM and IEI genes, and immunometabolic mechanisms may underlie a previously underappreciated intersection of these disorders.