Next-generation sequencing based newborn screening and comparative analysis with MS/MS

BACKGROUND

Newborn screening (NBS), such as tandem mass spectrometry (MS/MS), may yield false positive/negative results. Next-generation sequencing (NGS) has the potential to provide increased data output, efficiencies, and applications. This study aimed to analyze the types and distribution of pathogenic gene mutations in newborns in Huzhou, Zhejiang province, China and explore the applicability of NGS and MS/MS in NBS.

METHODS

Blood spot samples from 1263 newborns were collected. NGS was employed to screen for pathogenic variants in 542 disease-causing genes, and detected variants were validated using Sanger sequencing. Simultaneously, 26 inherited metabolic diseases (IMD) were screened using MS/MS. Positive or suspicious samples identified through MS/MS were cross-referenced with the results of NGS.

RESULTS

Among all newborns, 328 had no gene mutations detected. NGS revealed at least one gene mutation in 935 newborns, with a mutation rate of 74.0%. The top 5 genes were FLG, GJB2, UGT1A1, USH2A, and DUOX2. According to American College of Medical Genetics guidelines, gene mutations in 260 cases were classified as pathogenic or likely pathogenic mutation, with a positive rate of 20.6%. The top 5 genes were UGT1A1, FLG, GJB2, MEFV, and G6PD. MS/MS identified 18 positive or suspicious samples for IMD and 1245 negative samples. Verification of these cases by NGS results showed no pathogenic mutations, resulting in a false positive rate of 1.4% (18/1263).

CONCLUSION

NBS using NGS technology broadened the range of diseases screened, and enhanced the accuracy of diagnoses in comparison to MS/MS for screening IMD. Combining NGS and biochemical screening would improve the efficiency of current NBS.

Molecular testing in newborn screening: VUS burden among true positives and secondary reproductive limitations via expanded carrier screening panels

PURPOSE

Expanded carrier screening (ECS) gene panels have several limitations, including variable content, current knowledge of disease-causing variants, and differing reporting policies. This study evaluated if the disease-associated variants identified in affected neonates who screened positive by California newborn screening (NBS) for an inherited metabolic disorder (IMD) by tandem mass spectrometry (MS/MS) would likely be reported by ECS gene panels.

METHODS

Retrospective review of neonates referred by the California Department of Public Health for a positive NBS by multianalyte MS/MS from January 1, 2020 through June 30, 2021.

RESULTS

One hundred thirty-six neonates screened positive for ≥1 NBS MS/MS indication. Nineteen neonates (14%) were ultimately diagnosed with an IMD, all of whom had abnormal biochemical testing. Eighteen of the 19 underwent molecular testing; 10 (56%) neonates had ≥1 variants of uncertain significance, 9 of whom were of non-White ancestry. ECS panels would have been negative for 56% (20/36) of parents with an affected neonate, 85% (17/20) of whom were of non-White ancestry.

CONCLUSION

The number of variants of uncertain significance identified in this cohort highlights the need for more diversified variant databases. Due in part to the lack of diversity in currently sequenced populations, genomic sequencing cannot replace biochemical testing for the diagnosis of an IMD.

Result of a Pilot External Quality Assessment Scheme for Clinical Diagnosis of Inherited Metabolic Disorders in China

BACKGROUND

We aimed to evaluate the diagnostic capabilities of Chinese laboratories for inherited metabolic disorders (IMDs) using gas chromatography-mass spectrometry (GC-MS) on urine samples. Meanwhile, based on the result of the pilot external quality assessment (EQA) scheme, we hope to establish a standardized and reliable procedure for future EQA practice.

METHODS

We recruited laboratories that participated in the EQA of quantitative analysis of urinary organic acids with GC-MS before joining the surveys. In each survey, a set of five real urine samples was distributed to each participant. The participants should analyze the sample by GC-MS and report the "analytical result", "the most likely diagnosis", and "recommendation for further tests" to the NCCL before the deadline.

RESULTS

A total of 21 laboratories participated in the scheme. The pass rates were 94.4% in 2020 and 89.5% in 2021. For all eight IMDs tested, the analytical proficiency rates ranged from 84.7% - 100%, and the interpretational performance rate ranged from 88.2% - 97.0%. The performance on hyperphenylalaninemia (HPA), 3-methylcrotonyl-CoA carboxylase deficiency (MCCD), and ethylmalonic encephalopathy (EE) samples were not satisfactory.

CONCLUSIONS

In general, the participants of this pilot EQA scheme are equipped with the basic capability for qualitative organic acid analysis and interpretation of the results. Limited by the small size of laboratories and samples involved, this activity could not fully reflect the state of clinical practice of Chinese laboratories. NCCL will improve the EQA scheme and implement more EQA activities in the future.

From NAFLD to MASLD: When metabolic comorbidity matters

INTRODUCTION AND OBJECTIVES

In a recent development, a cohort of hepatologists has proposed altering the nomenclature of non-alcoholic fatty liver disease (NAFLD) to metabolic-associated steatotic liver disease (MASLD), accompanied by modified diagnostic criteria. Our objective was to investigate the effect of the revised definition on identifying significant hepatic fibrosis.

PATIENTS AND METHODS

From Jan 2009 to Dec 2022, a total of 428 patients with biopsy-proven hepatic steatosis were diagnosed with NAFLD. Patients were classified into subgroups according to MASLD and Cryptogenic-SLD diagnostic criteria. The clinical pathological features were compared between these two groups. Risk factors for significant fibrosis were analysed in the MASLD group. In total, 329 (76.9 %) patients were diagnosed with MASLD, and 99 (23.1 %) were diagnosed with Cryptogenic-SLD.

RESULTS

Those with MASLD exhibited a higher degree of disease severity regarding histology features than Cryptogenic-SLD. The prevalence of significant fibrosis increased from 13 % to 26.6 % for one and two criteria present to 42.5 % for meeting three or more cardiometabolic risk factor (CMRF) criteria (p = 0.001). ALB (aOR:0.94,95 %CI:0.90-1.00; p = 0.030), lower levels of PLT (aOR:0.99, 95 %CI:0.99-1.00; p < 0.001), and more metabolic comorbidities (aOR:1.42,95 %CI:1.14-1.78; p = 0.012) were independent risk factors of significant fibrosis in MASLD.

CONCLUSIONS

The new nomenclature of MASLD and SLD is more applicable to identifying significant fibrosis than NAFLD. Patients with three or more cardiometabolic risk factors are at higher risk of fibrosis.

Availability of psychological resources for parents receiving communication of positivity at newborn screening for metabolic diseases in Italy

Receiving information in the case of a positive or false-positive expanded newborn screening (ENBS) result for metabolic diseases is a stressful event. The availability of psychological support to families is crucial across the different communication steps and is recommended by different guidelines and position papers. However, more information is needed about the availability of psychological resources in the ENBS process. This national survey aimed to provide an overview of the availability of psychological resources for parents who received communication of positivity at the ENBS in the 23 Italian centers and how the support is provided to parents. An online survey was sent to the Heads of the ENBS centers asking about the availability of a clinical psychologist, their involvement in the ENBS process, and an estimation of parents receiving psychological support. More than 60% of the centers report having a clinical psychologist in the ENBS team; however, in more than 50% of cases, the psychologist does not participate in the consultation with parents (nor for the first consultation post-positivity or at confirmation of diagnosis). Furthermore, nearly 60% of the centers reported the experience of parental rejection of psychological sessions.  Conclusion: There is a need for harmonization among the Italian ENBS centers concerning the availability of psychological resources and how these resources are provided to families. Parents' needs remained only partially fulfilled. What is Known: • Receiving communication of positivity at the ENBS can be highly stressful for parents and requires adequate psychological support. • The guidelines recommend psychological support for parents during the ENBS process. What is New: • Only 14/23 (60.9%) of Italian ENBS centers have a clinical psychologist within the team. • In half of the consultations with parents receiving communication of positivity, the clinical psychologist is never involved.

Behavior Changes Associated with Metabolic Disease of Dogs and Cats

Like many physical disorders, the clinical signs associated with metabolic diseases affecting thyroid, adrenal, and pancreatic function are reflective of nonspecific changes in behavior. Additionally, patients who have underlying disorders associated with fear, anxiety, stress, conflict, and/or panic may be under treatment with medications that alter basal thyroid, glucose, and cortisol levels. Through reinforcement and punishment of behaviors associated with clinical signs caused by organic or iatrogenic endocrine disease, behaviors can be perpetuated and become persistent patterns. Screening all patients presenting with a primary behavior complaint or those with behavioral clinical signs of endocrine diseases is essential. Alleviating stress immediately while working up or treating metabolic disease reduces suffering and may stave off the adoption of behavior patterns more permanently.

OBMeta: a comprehensive web server to analyze and validate gut microbial features and biomarkers for obesity-associated metabolic diseases

MOTIVATION

Gut dysbiosis is closely associated with obesity and related metabolic diseases including type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). The gut microbial features and biomarkers have been increasingly investigated in many studies, which require further validation due to the limited sample size and various confounding factors that may affect microbial compositions in a single study. So far, it lacks a comprehensive bioinformatics pipeline providing automated statistical analysis and integrating multiple independent studies for cross-validation simultaneously.

RESULTS

OBMeta aims to streamline the standard metagenomics data analysis from diversity analysis, comparative analysis, and functional analysis to co-abundance network analysis. In addition, a curated database has been established with a total of 90 public research projects, covering three different phenotypes (Obesity, T2D, and NAFLD) and more than five different intervention strategies (exercise, diet, probiotics, medication, and surgery). With OBMeta, users can not only analyze their research projects but also search and match public datasets for cross-validation. Moreover, OBMeta provides cross-phenotype and cross-intervention-based advanced validation that maximally supports preliminary findings from an individual study. To summarize, OBMeta is a comprehensive web server to analyze and validate gut microbial features and biomarkers for obesity-associated metabolic diseases.

AVAILABILITY AND IMPLEMENTATION

OBMeta is freely available at: http://obmeta.met-bioinformatics.cn/.

IGAm: A novel index predicting long-term survival in patients with early-diagnosed inherited metabolic disorders

OBJECTIVES

The childhood mortality rate for IMDs is approximately 25 % in populations with no expanded newborn screening program. Although the factors that increase mortality risk are known, an index predicting long-term survival has yet to be established.

METHODS

Two hundred sixty patients who were hospitalized during the first month of their life were screened, and 94 patients diagnosed with IMDs were included in the study. Clinical and laboratory data were assessed to identify any independent prognostic factors for overall survival.

RESULTS

Among the 38 patients with IMDs in the exitus group, the presence of dysmorphism, extremity abnormalities, respiratory distress, cyanosis, elevated transaminases, elevated INR, hypoglycemia, hypoalbuminemia, metabolic acidosis, electrolyte imbalance and anemia were associated with poorer survival. Elevated INR (Hazard Ratio [HR]: 0.17, 95 % CI: 0.03-0.87, p=0.034), hypoglycemia (HR: 0.48, 95 % CI: 0.25-0.91, p=0.026) and hypoalbuminemia (HR: 0.09, 95 % CI: 0.03-0.26, p<0.001) were the independent prognostic factors for survival after adjusting for confounding factors. For the prediction of survival, INR, glucose, and albumin were used to structure a novel index (IGAm = INR-Glucose-Albumin metabolic index). The median survival was shorter in the IGAm-high group (2 or 3 points) than in the IGAm-low group (p<0.001). Harrell's c-index was 0.73 for the IGAm index.

CONCLUSIONS

The devised novel IGAm index can predict long-term survival in patients with IMDs, with a high IGAm index being associated with higher mortality in patients with IMDs.

[Evaluation and optimization of newborn screening by structured long-term follow-up-using the example of inherited metabolic diseases]

Newborn screening (NBS) is a highly successful secondary prevention program with the goal of preventing severe sequelae of congenital, mostly genetic, diseases by identifying them as early as possible, ideally in the pre-symptomatic period. Studies to date have shown the important achievements of NBS programs but also reveal a number of relevant weaknesses. These include the often incompletely understood natural history and phenotypic diversity of rare diseases as well as the inadequate ability to accurately predict individual disease severity at an early stage and thus the uncertainties in case definition, risk stratification, and treatment indication.In light of the rapid developments in high-throughput genetic technologies and the associated opportunities for substantial future expansion of NBS programs, it seems overdue to make structured long-term follow-up and the subsequent evaluation of the long-term health benefits mandatory for individuals with rare diseases identified through NBS. This article explains the importance of long-term follow-up for the evaluation and continuous optimization of the screening. Long-term clinical outcomes of people with inherited metabolic diseases identified by NBS are presented as examples.

Parents' experience of the communication process of positivity at newborn screening for metabolic diseases: A qualitative study

BACKGROUND

The process of receiving a communication of positivity for metabolic diseases at expanded newborn screening (ENBS) is extremely articulated, involves a variety of actors (parents, maternal and child departments, clinical centres and laboratories) and is open to a variety of outcomes from false positive to true positive cases. Receiving communication of positivity can be highly stressful for parents and requires an adequate communication process to give clear and reliable information without causing excessive worry. This qualitative study describes the parents' experience of receiving a communication of positivity to metabolic diseases at ENBS, and their assessment of the quality of the communication process and steps, with the main aim to identify the process' strengths and weaknesses and to advance tailored recommendations to improve the communication process.

METHOD

Fourteen in-depth, semi-structured phone interviews were conducted with parents whose children resulted positive to the ENBS. As part of the ENBS communication process, parents received a first phone call communication of positivity and a second in-person communication at metabolic clinical centres (MCC). The framework analysis method was used to organize the data and identify emerging themes.

RESULTS

Parents were largely dissatisfied with the quality and depth of the information received and with the way the healthcare staff delivered the first communication phone call, which failed to create a caring, empathic and safe setting. Many parents tried to reduce the uncertainty by searching online information or consulting with other providers. Nevertheless, the majority of parents described the in-person visit at MCC as clear, welcoming and reassuring.

CONCLUSION

More efforts are needed to improve the quality of the communication process of the ENBS. Guidelines, recommendations and standard scripts to communicate positivity are needed along with programmes and educational resources to train tailored communication skills.

Clinical and biochemical footprints of inherited metabolic diseases. XIV. Metabolic kidney diseases

Kidney disease is a global health burden with high morbidity and mortality. Causes of kidney disease are numerous, extending from common disease groups like diabetes and arterial hypertension to rare conditions including inherited metabolic diseases (IMDs). Given its unique anatomy and function, the kidney is a target organ in about 10% of known IMDs, emphasizing the relevant contribution of IMDs to kidney disease. The pattern of injury affects all segments of the nephron including glomerular disease, proximal and distal tubular damage, kidney cyst formation, built-up of nephrocalcinosis and stones as well as severe malformations. We revised and updated the list of known metabolic etiologies associated with kidney involvement and found 190 relevant IMDs. This represents the 14th of a series of educational articles providing a comprehensive and revised list of metabolic differential diagnoses according to system involvement.

Harmonization of distributed multi-center analysis based on dried blood spot reference materials supporting the screening of neonatal inherited metabolic disorders

BACKGROUND

The standardization of quantification data is critical for ensuring the reliability and measurement traceability in the screening of neonatal inherited metabolic disorders. However, the availability of national certified reference materials is limited in China.

METHODS

In this study, we developed a series of dried blood spot (DBS) reference materials containing 9 amino acids (AA) and 10 acylcarnitines (AC) for neonatal screening. Four levels of the reference materials were measured with tandem mass spectrometry (MS/MS) by seven laboratories using different commercial In Vitro Diagnostic Device (IVD) kits. Then, 100 clinical samples were measured using both derivatization and non-derivatization methods by the same laboratory.

RESULTS

We found high homogeneity and stability at all levels of the reference materials, with the coefficient of variation (CV) of the analytes less than 15%. These reference materials can be used to assess the testing capabilities of different laboratories. Our test also revealed that the correction factors (CF) calculated by the reference materials, along with clinical samples, could increase the consistency for different kits.

CONCLUSION

The DBS reference materials proposed in this study provide reliability for the harmonization in multi-center analysis for the screening of neonatal inherited metabolic disorders. And applying our correction method for the screening could improve the data consistency of the DBS samples prepared by different methods.

Menstrual Cycle Irregularity in Adolescence Is Associated With Cardiometabolic Health in Early Adulthood

Background Menstrual cycle irregularities are associated with cardiovascular and cardiometabolic disease. We tested associations between age at menarche and cycle irregularity in adolescence and cardiometabolic health in early adulthood in a subsample from the Pittsburgh Girls Study. Methods and Results Data from annual interviews were used to assess age at menarche and cycle irregularity (ie, greater or less than every 27-29 days) at age 15 years. At ages 22 to 25 years, cardiometabolic health was measured in a subsample of the Pittsburgh Girls Study (n=352; 68.2% Black), including blood pressure, waist circumference, and fasting serum insulin, glucose, and lipids. T tests were used for continuous data and odds ratios for dichotomous data to compare differences in cardiometabolic health as a function of onset and regularity of menses. Early menarche (ie, before age 11 years; n=52) was associated with waist circumference (P=0.043). Participants reporting irregular cycles (n=50) in adolescence had significantly higher levels of insulin, glucose, and triglycerides, and higher systolic and diastolic blood pressure (P values range from 0.035 to 0.005) and were more likely to have clinical indicators of cardiometabolic predisease in early adulthood compared with women who reported regular cycles (odds ratios ranged from 1.89 to 2.56). Conclusions Increasing rates and earlier onset of cardiovascular and metabolic disease among women, especially among Black women, highlights the need for identifying early and reliable risk indices. Menstrual cycle irregularity may serve this purpose and help elucidate the role of women's reproductive health in protecting and conferring risk for later cardiovascular and cardiometabolic diseases.

[Analysis of screening results for genetic metabolic diseases among 352 449 newborns from Changsha]

OBJECTIVE

To retrospectively analyze the screening results for genetic metabolic diseases among newborns from Changsha in order to determine the prevalence of single diseases and their mutational spectrum.

METHODS

352 449 neonates born from January 2016 to December 2021 in Changsha were subjected to tandem mass spectrometry. Suspected cases were further analyzed by biochemical and genetic testing.

RESULTS

Among the 352 449 newborns, 6 170 were positive for the screening, which yielded a positive rate of 1.75%. 5 437 cases were recalled, and 92 were confirmed, with the overall prevalence being 1∶3 831 and positive predictive value of 1.69%. Eighteen genetic metabolic diseases were detected among the 92 children, including 33 amino acid metabolic disorders, among which 20 were phenylalanine hydroxylase deficiency (60.60%). 17 cases had organic acid metabolic disorders, among which 4 were 2-methyl-dehydrogenase deficiency (23.50%). 42 had fatty acid metabolic disorders, among which 27 (64.30%) were primary carnitine deficiency and 12 were short-chain acyl-CoA dehydrogenase deficiency (28.60%). In total 90 genetic variants were identified, with the most common ones including c.51C>G, c.1400C>G, c.760C>T, c.1031A>G and c.1165A>G.

CONCLUSION

The common neonatal genetic metabolic diseases in Changsha include primary carnitine deficiency, phenylalanine hydroxylase deficiency and short-chain acyl-CoA dehydrogenase deficiency. The preliminary delineation of mutational spectrum for genetic metabolic diseases in Changsha can facilitate early diagnosis and intervention, so as to improve the quality of newborn population.

Knowledge and awareness level of healthcare professional candidate students on inherited metabolic diseases: a cross-sectional study

BACKGROUND

Healthcare professionals play a key role in the diagnosis, treatment, and follow-up of inborn metabolic diseases. However, the level of inborn metabolic disease knowledge of prospective healthcare professional students in our country has not yet been determined. Therefore, this study aimed to evaluate the level of knowledge of healthcare professional candidate students about inborn metabolic diseases.

METHODS

The knowledge levels of 761 students enrolled in the Department of Nutrition and Dietetics, Child Development, Midwifery, Occupational Therapy, Audiology, Health Management and Social Work at Gülhane Faculty of Health Sciences, Health Sciences University, were evaluated through a questionnaire using a face-to-face interview technique. Correct answers to the questions measuring the level of knowledge were scored as "1", and incorrect answers were scored as "0".

RESULTS

The mean knowledge-level score of the individuals was 14.23 ± 4.56. A total of 56.0% of individuals had heard about inborn metabolic diseases before, 37.8% had heard of rare disease organizations/platforms before, and 16.8% had encountered an awareness campaign about inborn metabolic diseases. The level of exposure to awareness-raising campaigns, department of education, and grade level were shown to be factors affecting knowledge levels.

CONCLUSION

It is necessary to improve the awareness and knowledge levels of health professional candidates involved in the treatment of inborn metabolic diseases. Education curricula in health sciences faculties should be evaluated with this aspect.

China nationwide landscape of 16 types inherited metabolic disorders: a retrospective analysis on 372,255 clinical cases

BACKGROUND

Inherited metabolic disorders (IMDs) usually occurs at young age and hence it severely threatening the health and life of young people. While so far there lacks a comprehensive study which can reveals China's nationwide landscape of IMDs. This study aimed to evaluate IMDs incidence and regional distributions in China at a national and province level to guide clinicians and policy makers.

METHODS

The retrospective study conducted from January 2012 to March 2021, we analyzed and characterized 372255 cases' clinical test information and diagnostic data from KingMed Diagnostics Laboratory. The samples were from 32 provincial regions of China, the urine organic acids were detected by gas chromatography-mass spectrometry (GC-MS), amino acids and acylcarnitines in dried blood spots were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). We did a statistical analysis of the distribution of the 16 most common IMDs in amino acid disorders and organic acidemias, and then paid special attention to analyze the age and regional distributions of different IMDs. The statistical analyses and visualization analysis were performed with the programming language R (version 4.2.1).

RESULTS

There were 4911 positive cases diagnosed, which was 1.32% of the total sample during the ten-year study period. Most diseases tended to occur at ages younger than 18 year-old. The Ornithine Transcarbamylase Deficiency tended to progress on male infants who were less than 28 days old. While the peak of the positive case number of Citrin Deficiency disease (CD) was at 1-6 months. Different IMDs' had different distribution patterns in China's provinces. Methylmalonic Acidemias and Hyperphenylalaninemia had an imbalanced distribution pattern in China and its positive rate was significantly higher in North China than South China. Conversely, the positive rate of CD was significantly higher in South China than North China.

CONCLUSIONS

Results of this work, such as the differences in distribution pattern of different diseases in terms of age, region, etc. provide important insights and references for clinicians, researchers and healthcare policy makers. The policy makers could optimize the better health screening programs for covering children and infants in specific ages and regions based on our findings.

The cardio-renal-metabolic connection: a review of the evidence

Type 2 diabetes (T2D), cardiovascular disease (CVD) and chronic kidney disease (CKD), are recognized among the most disruptive public health issues of the current century. A large body of evidence from epidemiological and clinical research supports the existence of a strong interconnection between these conditions, such that the unifying term cardio-metabolic-renal (CMR) disease has been defined. This coexistence has remarkable epidemiological, pathophysiologic, and prognostic implications. The mechanisms of hyperglycemia-induced damage to the cardio-renal system are well validated, as are those that tie cardiac and renal disease together. Yet, it remains controversial how and to what extent CVD and CKD can promote metabolic dysregulation. The aim of this review is to recapitulate the epidemiology of the CMR connections; to discuss the well-established, as well as the putative and emerging mechanisms implicated in the interplay among these three entities; and to provide a pathophysiological background for an integrated therapeutic intervention aiming at interrupting this vicious crosstalks.

Clinical Presentation of Inherited Metabolic Diseases in Newborns Hospitalised in an Intensive Care Unit

BACKGROUND

The first clinical manifestations of inherited metabolic diseases occur in the neonatal period in up to half of cases, often with nonspecific symptoms, making their recognition challenging. This study aimed to characterise inherited metabolic disease cases with neonatal presentation requiring admission to the paediatric intensive care unit in a Portuguese reference centre for inherited metabolic diseases.

MATERIAL AND METHODS

An observational study with retrospective data collection was performed, including all newborns with an inherited metabolic disease admitted to the pediatric intensive care unit between June 2011 and June 2022. Three 'pathophysiological' groups were defined: cases due to small molecules, energy deficiency and complex molecules.

RESULTS

Twenty newborns, with a median age at admission of 7.5 days, were included. Thirteen (65%) were female, sixteen (80%) had a small molecule disorder, and four (20%) had diseases of energy defects. Neurological manifestations were the most common, with most newborns presenting symptomatically in the first week of life. There was no difference between the groups in neurological, cardiac, and hepatic involvement and shock at presentation. A symptom-free interval was more frequent in patients with small molecule disorders than the others (p=0.01). The main metabolic changes found were altered plasma amino acids (n=13) and organic aciduria (n=10), creatine kinase elevation (n=13), hyperlactatemia (n=12), metabolic acidosis with increased anion gap (n=8) and hyperammonaemia (n=7). Newborn screening of metabolites helped make a diagnosis in 60% of cases. Five newborns died due to multiorgan failure (n=3) or refractory cardiogenic shock (n=1), and in one, therapeutic efforts were limited due to an adverse neurological prognosis.

CONCLUSION

Although the symptoms and signs are often nonspecific, we should suspect inherited metabolic disease when a newborn presents with neurological symptoms after a symptom-free period, however short it might be. Newborns with suspected inherited metabolic disease should be evaluated with simple biochemical tests, and newborn screening should be urgently expanded to start specific treatment earlier, reducing mortality and morbidity.

Boron-Containing Compounds for Prevention, Diagnosis, and Treatment of Human Metabolic Disorders

The application of natural and synthetic boron-containing compounds (BCC) in biomedical field is expanding. BCC have effects in the metabolism of living organisms. Some boron-enriched supplements are marketed as they exert effects in the bone and skeletal muscle; but also, BCC are being reported as acting on the enzymes and transporters of membrane suggesting they could modify the carbohydrate metabolism linked to some pathologies of high global burden, as an example is diabetes mellitus. Also, some recent findings are showing effects of BCC on lipid metabolism. In this review, information regarding the effects and interaction of these compounds was compiled, as well as the potential application for treating human metabolic disorders is suggested.

Wearable and digital devices to monitor and treat metabolic diseases

Cardiometabolic diseases are a major public-health concern owing to their increasing prevalence worldwide. These diseases are characterized by a high degree of interindividual variability with regards to symptoms, severity, complications and treatment responsiveness. Recent technological advances, and the growing availability of wearable and digital devices, are now making it feasible to profile individuals in ever-increasing depth. Such technologies are able to profile multiple health-related outcomes, including molecular, clinical and lifestyle changes. Nowadays, wearable devices allowing for continuous and longitudinal health screening outside the clinic can be used to monitor health and metabolic status from healthy individuals to patients at different stages of disease. Here we present an overview of the wearable and digital devices that are most relevant for cardiometabolic-disease-related readouts, and how the information collected from such devices could help deepen our understanding of metabolic diseases, improve their diagnosis, identify early disease markers and contribute to individualization of treatment and prevention plans.

Biochemical, Genetic and Clinical Diagnostic Approaches to Autism-Associated Inherited Metabolic Disorders

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders characterized by impaired social interaction, limited communication skills, and restrictive and repetitive behaviours. The pathophysiology of ASD is multifactorial and includes genetic, epigenetic, and environmental factors, whereas a causal relationship has been described between ASD and inherited metabolic disorders (IMDs). This review describes biochemical, genetic, and clinical approaches to investigating IMDs associated with ASD. The biochemical work-up includes body fluid analysis to confirm general metabolic and/or lysosomal storage diseases, while the advances and applications of genomic testing technology would assist with identifying molecular defects. An IMD is considered likely underlying pathophysiology in ASD patients with suggestive clinical symptoms and multiorgan involvement, of which early recognition and treatment increase their likelihood of achieving optimal care and a better quality of life.

MAFLD: How is it different from NAFLD?

"Metabolic dysfunction-associated fatty liver disease (MAFLD)" is the term suggested in 2020 to refer to fatty liver disease related to systemic metabolic dysregulation. The name change from nonalcoholic fatty liver disease (NAFLD) to MAFLD comes with a simple set of criteria to enable easy diagnosis at the bedside for the general medical community, including primary care physicians. Since the introduction of the term, there have been key areas in which the superiority of MAFLD over the traditional NAFLD terminology has been demonstrated, including for the risk of liver and extrahepatic mortality, disease associations, and for identifying high-risk individuals. Additionally, MAFLD has been adopted by a number of leading pan-national and national societies due to its concise diagnostic criterion, removal of the requirement to exclude concomitant liver diseases, and reduction in the stigma associated with this condition. The current article explores the differences between MAFLD and NAFLD diagnosis, areas of benefit, some potential limitations, and how the MAFLD terminology has opened up new fields of research.

Phase Angle as a Potential Screening Tool in Adults with Metabolic Diseases in Clinical Practice: A Systematic Review

BACKGROUND

Phase angle (PhA) has been used as mortality prognostic, but there are no studies about its possible use as a screening tool. Therefore, an assessment of the possible utility of PhA in clinical practice is required. The aim of this systematic review was to explore all recent available evidence of PhA, and its possible utility as a screening tool in clinical practice in subjects with chronic metabolic diseases.

MATERIALS AND METHODS

This systematic review was performed and written as stated in the PRISMA 2020 guidelines. The search was conducted in PubMed, ScienceDirect and SciElo. In order to be considered eligible, within the entire search, only articles involving PhA and their utility in metabolic diseases were included.

RESULTS

PhA was associated with hyperuricemia and vitamin D deficiency in obese subjects, and decreased cardiovascular risk and malnutrition in hospitalized patients.

CONCLUSION

PhA may be a potential screening tool in clinical practice to evaluate different biomarkers, cardiovascular risk, and nutritional diagnosis in metabolic diseases in adults.

Lipidomics-Paving the Road towards Better Insight and Precision Medicine in Rare Metabolic Diseases

Even though the application of Next-Generation Sequencing (NGS) has significantly facilitated the identification of disease-associated mutations, the diagnostic rate of rare diseases is still below 50%. This causes a diagnostic odyssey and prevents specific treatment, as well as genetic counseling for further family planning. Increasing the diagnostic rate and reducing the time to diagnosis in children with unclear disease are crucial for a better patient outcome and improvement of quality of life. In many cases, NGS reveals variants of unknown significance (VUS) that need further investigations. The delineation of novel (lipid) biomarkers is not only crucial to prove the pathogenicity of VUS, but provides surrogate parameters for the monitoring of disease progression and therapeutic interventions. Lipids are essential organic compounds in living organisms, serving as building blocks for cellular membranes, energy storage and signaling molecules. Among other disorders, an imbalance in lipid homeostasis can lead to chronic inflammation, vascular dysfunction and neurodegenerative diseases. Therefore, analyzing lipids in biological samples provides great insight into the underlying functional role of lipids in healthy and disease statuses. The method of choice for lipid analysis and/or huge assemblies of lipids (=lipidome) is mass spectrometry due to its high sensitivity and specificity. Due to the inherent chemical complexity of the lipidome and the consequent challenges associated with analyzing it, progress in the field of lipidomics has lagged behind other omics disciplines. However, compared to the previous decade, the output of publications on lipidomics has increased more than 17-fold within the last decade and has, therefore, become one of the fastest-growing research fields. Combining multiple omics approaches will provide a unique and efficient tool for determining pathogenicity of VUS at the functional level, and thereby identifying rare, as well as novel, genetic disorders by molecular techniques and biochemical analyses.

Long-term anthropometric development of individuals with inherited metabolic diseases identified by newborn screening

Newborn screening (NBS) for inherited metabolic diseases (IMDs) substantially shortens a patient's journey. It enables the early start of metabolic treatment which might prevent potentially lethal neonatal disease manifestations, while promoting favorable development and long-term clinical outcomes. This study aims to assess growth in screened individuals with IMDs under different dietary regimes. Anthropometric data (3585 prospective measures) of 350 screened individuals with IMDs born between 1999 and 2018 and participating in a German prospective multicenter observational study were evaluated. Overall, birth measures were within the reference ranges, suggesting unaffected prenatal growth, except for phenylketonuria (weight) and glutaric aciduria Type 1 (head circumference). After birth, longitudinal analysis of anthropometric measures revealed a loss of height standard deviation score (SDS; -0.5 SDS; p < 0.0001), head circumference SDS (-0.2 SDS; p = 0.0028), but not for weight SDS (0.1 SDS; p = 0.5097) until the age of 18 years, while BMI SDS increased (0.4 SDS; p < 0.0001). The significant interaction with age and diet groups was pronounced for the linear growth in individuals receiving diets being low in protein, long-chain triglycerides, and galactose (p < 0.001). Identification by NBS and subsequent early (dietary) treatment cannot completely protect against alterations in growths. Disease-specific (e.g., metabolic impairments, neurotoxins) and dietary-specific (e.g., diets reduced in protein) factors may have an amplified impact on longitudinal growth. Therefore, alongside other important follow-ups, the continuous observation of the anthropometric development of screened individuals with IMDs needs special attention to early identify and support individuals at risk.

Whole-Body Mouse Fluxomic Analysis to Detect Metabolic Disruptions Associated with Microcephaly: Using 13C Isotopes

Diverse metabolic disorders can disrupt brain growth, and analyzing metabolism in animal models of microcephaly may reveal new mechanisms of pathogenesis. The metabolism of functioning cells in a living organism is constantly changing in response to a changing environment, circadian rhythms, consumed food, drugs, progressing sicknesses, aging, and many other factors. Metabolic profiling can give important insights into the working machinery of the cell. However, a frozen snapshot of the interconnected, complex network of reactions gives very limited information about this system. Flux analysis using stable isotope labels enables more robust metabolic studies that consider interrogate metabolite processing and changes in molecular concentrations over time.

Diagnosis of Extracellular Vesicles in Cardiovascular and Metabolic Diseases

Early detection and identification of those with or at increased risk for cardiovascular disease (CVD) and metabolic dysfunction is crucial for improving disease management and prognosis. Given the complex, multifactorial nature of the pathogenesis of the CVD and metabolic dysfunction, it is essential to have biomarkers that encompass the multiple facets of disease development. The uniquely ubiquitous nature and functionality of extracellular vesicles (EVs) in various disease pathologies can provide novel insight into both diagnosis and prognosis while further improving assessments used in clinical and research practice. Herein we summarize the use of EV count and content (including miRNA and protein) in diagnosis of CVD, obesity, metabolic syndrome, and type 2 diabetes (T2D), as well as highlight the potential utility for enhancing determination of prognosis and long-term complications in these clinical populations. Although the results are promising, future work is needed in both methodology and in relation to other factors such as sex and medications, in order to apply these findings in clinical practice.

Clinical and biochemical footprints of inherited metabolic disease. V. Cerebral palsy phenotypes

Cerebral palsy is the most common physical disability of childhood describing a heterogeneous group of neurodevelopmental disorders that cause activity limitation, but often are accompanied by disturbances of sensation, perception, cognition, communication and behavior, or by epilepsy. Inborn errors of metabolism have been reported in the literature as presenting with features of cerebral palsy. We reviewed and updated the list of metabolic disorders known to be associated with symptoms suggestive of cerebral palsy and found more than 150 relevant IEMs. This represents the fifth of a series of articles attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnosis according to system involvement.

Proteomics in Inherited Metabolic Disorders

Inherited metabolic disorders (IMD) are rare medical conditions caused by genetic defects that interfere with the body's metabolism. The clinical phenotype is highly variable and can present at any age, although it more often manifests in childhood. The number of treatable IMDs has increased in recent years, making early diagnosis and a better understanding of the natural history of the disease more important than ever. In this review, we discuss the main challenges faced in applying proteomics to the study of IMDs, and the key advances achieved in this field using tandem mass spectrometry (MS/MS). This technology enables the analysis of large numbers of proteins in different body fluids (serum, plasma, urine, saliva, tears) with a single analysis of each sample, and can even be applied to dried samples. MS/MS has thus emerged as the tool of choice for proteome characterization and has provided new insights into many diseases and biological systems. In the last 10 years, sequential window acquisition of all theoretical fragmentation spectra mass spectrometry (SWATH-MS) has emerged as an accurate, high-resolution technique for the identification and quantification of proteins differentially expressed between healthy controls and IMD patients. Proteomics is a particularly promising approach to help obtain more information on rare genetic diseases, including identification of biomarkers to aid early diagnosis and better understanding of the underlying pathophysiology to guide the development of new therapies. Here, we summarize new and emerging proteomic technologies and discuss current uses and limitations of this approach to identify and quantify proteins. Moreover, we describe the use of proteomics to identify the mechanisms regulating complex IMD phenotypes; an area of research essential to better understand these rare disorders and many other human diseases.

Impacts of metabolic disorders on short- and long-term mortality after coronary artery surgery in the elderly

BACKGROUND

Elderly patients undergoing cardiac operation often suffer various metabolic comorbidities, such as diabetes mellitus (DM) and obesity. The metabolic disorders in these individuals are widely considered to be possible predisposing factors for unfavourable prognosis. This retrospective study was aimed to determine the association of metabolic diseases with the mortality of elderly patients after coronary artery bypass grafting (CABG) and to identify the protective or risk factors related to their short- and long-term survival.

METHODS

Totally 684 patients aged 75 years or above undergoing isolated CABG were evaluated retrospectively. There were two groups depending on the body mass index (BMI): an overweight and obesity group (n = 354) and a normal weight and lean group (n = 330). Propensity score matching (PSM) was performed to adjust baseline clinical characteristics, which reduced confounding bias. The short-term postoperative mortality was tested via logistic regression. Kaplan-Meier and Cox regression analyses were done to compute the overall survival in each group and to identify relevant variables associated with all-cause mortality, respectively.

RESULTS

The prevalence rates of metabolic comorbidities in the total cohort were: diabetes mellitus (32.5%), overweight or obesity (51.8%) and hypertension (72.8%). The 30-day postoperative mortality was 5.1% and the long-term mortality was 15.25% at a median 46.2-month follow-up (1.0-178.6 months). The 30-day postoperative mortality was relevant to DM, diseased coronary arteries, New York Heart Association class, intra-aortic balloon pump and emergency surgery. The long-term mortality was negatively associated with overweight and obesity. Univariate and multivariate logistic regression recognized DM as an adverse factor related with 30-day postoperative mortality whether before or after PSM. The long-term mortality was not significantly relevant with DM (HR = 0.753, 95% CI 0.402-1.411). Overweight or obesity was not the risk factor of 30-day postoperative mortality (OR = 1.284, 95% CI 0.426-3.868), but was the protective factor of long-term survival (HR = 0.512, 95% CI 0.279-0.939).

CONCLUSIONS

The "obesity paradox" exists regarding the prognosis of individuals aged ≥ 75, which was presented as lower long-term mortality no matter from all cause or cardio-cerebrovascular cause in patients with BMI ≥ 24. Trial registration ChiCTR2200061869 (05/07/2022).

Eye movement disorders in inborn errors of metabolism: A quantitative analysis of 37 patients

Inborn errors of metabolism are genetic disorders that need to be recognized as early as possible because treatment may be available. In late-onset forms, core symptoms are movement disorders, psychiatric symptoms, and cognitive impairment. Eye movement disorders are considered to be frequent too, although specific knowledge is lacking. We describe and analyze eye movements in patients with an inborn error of metabolism, and see whether they can serve as an additional clue in the diagnosis of particularly late-onset inborn errors of metabolism. Demographics, disease characteristics, and treatment data were collected. All patients underwent a standardized videotaped neurological examination and a video-oculography. Videos are included. We included 37 patients with 15 different inborn errors of metabolism, including 18 patients with a late-onset form. With the exception of vertical supranuclear gaze palsy in Niemann-Pick type C and external ophthalmolplegia in Kearns-Sayre syndrome, no relation was found between the type of eye movement disorder and the underlying metabolic disorder. Movement disorders were present in 29 patients (78%), psychiatric symptoms in 14 (38%), and cognitive deficits in 26 patients (70%). In 87% of the patients with late-onset disease, eye movement disorders were combined with one or more of these core symptoms. To conclude, eye movement disorders are present in different types of inborn errors of metabolism, but are often not specific to the underlying disorder. However, the combination of eye movement disorders with movement disorders, psychiatric symptoms, or cognitive deficits can serve as a diagnostic clue for an underlying late-onset inborn error of metabolism.

The role of ERNDIM diagnostic proficiency schemes in improving the quality of diagnostic testing for inherited metabolic diseases

External quality assurance (EQA) is crucial to monitor and improve the quality of biochemical genetic testing. ERNDIM (www.erndim.org), established in 1994, aims at reliable and standardized procedures for diagnosis, treatment and monitoring of inherited metabolic disease (IMD) by providing EQA schemes and educational activities. Currently, ERNDIM provides 16 different EQA schemes including quantitative schemes for various metabolite groups, and interpretive schemes such as diagnostic proficiency testing (DPT). DPT schemes focus on the ability of laboratories to correctly identify and interpret abnormalities in authentic urine samples across a wide range of IMDs. In the DPT schemes, six samples each year are distributed together with clinical information. Laboratories choose and perform the tests needed to reach a diagnosis. Data were collected on 345 samples, distributed to up to 105 laboratories worldwide. Diagnostic proficiency (the % of total points possible for all participating laboratories within a scheme for analysis and interpretation) ranged widely: amino acid disorders (n = 20), range 33%-100%, mean 84%; organic acid disorders (n = 35), range 14%-100%, mean 84%; lysosomal storage disorders (n = 13), range 20%-97%, mean 73%; purine/pyrimidine disorders (n = 9), range 37%-100%, mean 70%; miscellaneous disorders (n = 8), range 17%-100%, mean 65%; no IMD, range 65%-95%, mean 85%. When a sample with the same disorder was distributed in a subsequent survey, performance improved in 75 cases with no improvement seen in 32, suggesting overall improvement of performance. ERNDIM diagnostic proficiency testing is a valuable activity which can help to assess laboratory performance, identify methodological/technical challenges, be informative during quality audits and contribute to a better clinical appreciation of diagnostic uncertainty.

[Practical approach to the diagnosis of inherited metabolic diseases]

Inborn errors of metabolism constitute a growing group of rare diseases with usual neurological impact. Heterogeneous in clinical and biochemical aspects, its diagnosis and treatment are difficult. Advances in its knowledge, in diagnostic methods and in its treatments, highlight the importance of a timely diagnosis, the gateway to access to early medical intervention. The neuropediatrician's suspicion in different clinical situations is very relevant. This article aims to be a practical contribution to facilitate their recognition.

New Horizons: the value of UK Biobank to research on endocrine and metabolic disorders

UK Biobank is an intensively characterized prospective study of 500 000 men and women, aged 40 to 69 years when recruited, between 2006 and 2010, from the general population of the United Kingdom. Established as an open-access resource for researchers worldwide to perform health research that is in the public interest, UK Biobank has collected (and continues to collect) a vast amount of data on genetic, physiological, lifestyle, and environmental factors, with prolonged follow-up of heath conditions through linkage to administrative electronic health records. The study has already demonstrated its unique value in enabling research into the determinants of common endocrine and metabolic diseases. The importance of UK Biobank, heralded as a flagship project for UK health research, will only increase over time as the number of incident disease events accrue, and the study is enhanced with additional data from blood assays (such as whole-genome sequencing, metabolomics, and proteomics), wearable technologies (including physical activity and cardiac monitors), and body imaging (magnetic resonance imaging and dual-energy X-ray absorptiometry). This unique research resource is likely to transform our understanding of the causes, diagnosis, and treatment of many endocrine and metabolic disorders.

[The correlations of abdominal adipose tissue with anthropometric and metabolic parameters in obese children by magnetic resonance imaging]

Objective: To explore abdominal fat mass distribution and contents among obese children via magnetic resonance imaging (MRI), and analyze the correlations of abdominal adipose tissue with anthropometric and metabolic parameters. Methods: Cross-sectional study. There were 60 obese children admitted to the Children's Health Care Department and Endocrinology Department at Children's Hospital of Nanjing Medical University from July 2016 to December 2018. Children's gender, age, height, weight, body composition, waist circumference and blood pressure were recorded. The levels of fasting blood glucose, lipids, insulin were measured, and liver ultrasound was performed, and the body mass index Z score (BMI-Z), waist-to-height ratio (WHtR) and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated. In addition, contents of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and total abdominal adipose tissue (TAAT) were calculated according to feedback of abdominal MRI scan images. The associations between the contents of abdominal adipose tissue, physical examination status and metabolic disorders among obese children were analyzed through correlation analysis and regression analysis. Receiver operating characteristic (ROC) curve was used to compare the accuracy of fat mass in different parts of the abdomen in predicting their metabolic disorders. Results: A total of 60 children were enrolled in the study, included 44 boys and 16 girls, with age of (9.2±1.4) years. The contents of SAT, VAT and TAAT among the 60 children were positively associated with BMI-Z (r=0.60, 0.46, 0.59), body fat percentage (r=0.64, 0.67, 0.68) and waist-to-height ratio (r=0.60, 0.57, 0.61) (all P<0.01). Meanwhile, contents of SAT and TAAT were also positively correlated with systolic blood pressure (r=0.47, 0.49), triglyceride (r=0.33, 0.35) and HOMA-IR (r=0.33, 0.28)(all P<0.05). In order to adjust the confounding effects among various variables, regression analysis was applied and the result showed that the body fat percentage (β=0.59, 0.66, 0.65) and waist-to-height ratio (β=0.53, 0.63, 0.59) were most related to abdominal fat contents (all P<0.01), including SAT, VAT and TAAT among obese children. According to ROC, SAT had outstanding evaluation performances for the diagnosis of insulin resistance and metabolic syndrome, while VAT had excellent evaluation performances for non-alcoholic fatty liver disease (area under curve=0.68, 0.69, 0.69, 95%CI 0.54-0.82, 0.55-0.84, 0.53-0.85, P=0.017, 0.014, 0.019). Conclusions: As one of the best indexes, body fat percentage and WHtR can be used to predict the contents of SAT, VAT and TAAT among obese children. With the increase of abdominal SAT or VAT, the risks for insulin resistance, metabolic syndrome and non-alcoholic fatty liver disease would increase. Assessment of abdominal fat and metabolic risks in obese children should combine BMI-Z with waist circumference and body composition analysis.

Towards Multiplexed and Multimodal Biosensor Platforms in Real-Time Monitoring of Metabolic Disorders

Metabolic syndrome (MS) is a cluster of conditions that increases the probability of heart disease, stroke, and diabetes, and is very common worldwide. While the exact cause of MS has yet to be understood, there is evidence indicating the relationship between MS and the dysregulation of the immune system. The resultant biomarkers that are expressed in the process are gaining relevance in the early detection of related MS. However, sensing only a single analyte has its limitations because one analyte can be involved with various conditions. Thus, for MS, which generally results from the co-existence of multiple complications, a multi-analyte sensing platform is necessary for precise diagnosis. In this review, we summarize various types of biomarkers related to MS and the non-invasively accessible biofluids that are available for sensing. Then two types of widely used sensing platform, the electrochemical and optical, are discussed in terms of multimodal biosensing, figure-of-merit (FOM), sensitivity, and specificity for early diagnosis of MS. This provides a thorough insight into the current status of the available platforms and how the electrochemical and optical modalities can complement each other for a more reliable sensing platform for MS.

Application of metabolite set enrichment analysis on untargeted metabolomics data prioritises relevant pathways and detects novel biomarkers for inherited metabolic disorders

Untargeted metabolomics (UM) allows for the simultaneous measurement of hundreds of metabolites in a single analytical run. The sheer amount of data generated in UM hampers its use in patient diagnostics because manual interpretation of all features is not feasible. Here, we describe the application of a pathway-based metabolite set enrichment analysis method to prioritise relevant biological pathways in UM data. We validate our method on a set of 55 patients with a diagnosed inherited metabolic disorder (IMD) and show that it complements feature-based prioritisation of biomarkers by placing the features in a biological context. In addition, we find that by taking enriched pathways shared across different IMDs, we can identify common drugs and compounds that could otherwise obscure genuine disease biomarkers in an enrichment method. Finally, we demonstrate the potential of this method to identify novel candidate biomarkers for known IMDs. Our results show the added value of pathway-based interpretation of UM data in IMD diagnostics context.

Genetic Diagnosis in a Cohort of Adult Patients with Inherited Metabolic Diseases: A Single-Center Experience

Inherited metabolic diseases (IMDs) are genetic conditions that result in metabolism alterations. Although research-based Next Generation Sequencing (NGS) testing for IMD has been recently implemented, its application in a clinical diagnostic setting remains challenging. Thus, we aimed at investigating the genetic diagnostic approach in a cohort of adult patients with IMDs referred to our adult metabolic unit. A retrospective analysis was performed collecting demographic, clinical, and genetic data of patients referred to the Adult Metabolic Unit in Padua from November 2017 to March 2022. In total, 108 adult patients (mean age: 33 years ± 17, 55% women) were enrolled in the study, and 83 (77%) of the patients transitioned from the pediatric metabolic clinics. The most prevalent groups of IMDs were disorders of complex molecule degradation (32 patients) and disorders of amino acid metabolism (31) followed by disorders of carbohydrates (26). Molecular genetic diagnosis was reported by 69 (64%) patients, with the higher rate reported by patients referred from specialty other than pediatric (88% vs. 55%). Almost all the subjects (92%) with disorders of complex molecule degradation had a genetic diagnosis. Patients with disorders of amino acid metabolism and disorders of carbohydrates had almost the same rate of genetic test (39% and 38%, respectively). Among the patients without a genetic diagnosis that we tested, two novel mutations in disease-associated genes were detected. In our single-center cohort, a consistent proportion (36%) of subjects with IMDs reaches the adulthood without a genetic demonstration of the disease. This lack, even if in some cases could be related to disease-specific diagnostic approach or to different disease onset, could be detrimental to patient management and impact to some of the specific needs of adult subjects.

[Disease spectrum analysis of children with inherited metabolic diseases detected by gas chromatography-mass spectrometry of urinary organic acids]

Objective: To investigate the spectrum of amino acid, organic acid, and fatty acid oxidative metabolic diseases in children diagnosed by detecting urinary organic acid levels using gas chromatography-mass spectrometry. Methods: From January 2005 to December 2021, clinical data of 2 461 children diagnosed with inherited metabolic diseases (IMD) by gas chromatography-mass spectrometry, in combination with tandem mass spectrometry and genetic testing in Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were retrospectively analyzed. Results: Among 2 461 children, 1 446 were male and 1 051 were female. A total of 32 types of IMD were detected among 2 461 patients, which included 10 amino acid disorders in 662 cases (26.9%), 6 common diseases were hyperphenylalaninemia, citrin deficiency, ornithine carbamoyltransferase deficiency, maple syrup urine disease, alkaptonuria, and tyrosinemia-I, 17 types of organic acidemias in 1 683 cases (68.4%), 6 common diseases were methylmalonic acidemia, propionic acidemia, valeric acidemia-type Ⅰ, isovaleric acidemia, 3-methylcrotonyl-CoA carboxylase deficiency and multiple carboxylase deficiency and 5 fatty acid β oxidative defects in 116 cases (4.7%), 2 common diseases were multiple acyl-CoA dehydrogenase deficiency and short-chain acyl-CoA dehydrogenase deficiency). Conclusion: Among the diseases diagnosed by analyzing urinary organic acid profiling with gas chromatography-mass spectrometry, the most common are organic acidemias, followed by amino acid disorders and fatty acid oxidation defects.

Exosomes as novel biomarkers in metabolic disease and obesity-related cancers

Exosomes include plasma-transported vesicles that are secreted by human tissues and reflect metabolic status. The profile of exosomes (particularly microRNA content) is altered in metabolic disease. In type 2 diabetes mellitus, exosomes circulating in plasma induce transcriptional changes related to tumour progression and pro-metastatic phenotypes in target cancer cells, potentially linking obesity to cancer progression and metastasis.

Clinical diagnosis of metabolic disorders using untargeted metabolomic profiling and disease-specific networks learned from profiling data

Untargeted metabolomics is a global molecular profiling technology that can be used to screen for inborn errors of metabolism (IEMs). Metabolite perturbations are evaluated based on current knowledge of specific metabolic pathway deficiencies, a manual diagnostic process that is qualitative, has limited scalability, and is not equipped to learn from accumulating clinical data. Our purpose was to improve upon manual diagnosis of IEMs in the clinic by developing novel computational methods for analyzing untargeted metabolomics data. We employed CTD, an automated computational diagnostic method that "connects the dots" between metabolite perturbations observed in individual metabolomics profiling data and modules identified in disease-specific metabolite co-perturbation networks learned from prior profiling data. We also extended CTD to calculate distances between any two individuals (CTDncd) and between an individual and a disease state (CTDdm), to provide additional network-quantified predictors for use in diagnosis. We show that across 539 plasma samples, CTD-based network-quantified measures can reproduce accurate diagnosis of 16 different IEMs, including adenylosuccinase deficiency, argininemia, argininosuccinic aciduria, aromatic L-amino acid decarboxylase deficiency, cerebral creatine deficiency syndrome type 2, citrullinemia, cobalamin biosynthesis defect, GABA-transaminase deficiency, glutaric acidemia type 1, maple syrup urine disease, methylmalonic aciduria, ornithine transcarbamylase deficiency, phenylketonuria, propionic acidemia, rhizomelic chondrodysplasia punctata, and the Zellweger spectrum disorders. Our approach can be used to supplement information from biochemical pathways and has the potential to significantly enhance the interpretation of variants of uncertain significance uncovered by exome sequencing. CTD, CTDdm, and CTDncd can serve as an essential toolset for biological interpretation of untargeted metabolomics data that overcomes limitations associated with manual diagnosis to assist diagnosticians in clinical decision-making. By automating and quantifying the interpretation of perturbation patterns, CTD can improve the speed and confidence by which clinical laboratory directors make diagnostic and treatment decisions, while automatically improving performance with new case data.

Clinical and biochemical footprints of inherited metabolic disorders. VII. Ocular phenotypes

Ocular manifestations are observed in approximately one third of all inherited metabolic disorders (IMDs). Although ocular involvement is not life-threatening, it can result in severe vision loss, thereby leading to an additional burden for the patient. Retinal degeneration with or without optic atrophy is the most frequent phenotype, followed by oculomotor problems, involvement of the cornea and lens, and refractive errors. These phenotypes can provide valuable clues that contribute to its diagnosis. In this issue we found 577 relevant IMDs leading to ophthalmologic manifestations. This article is the seventh of a series attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnoses according to system involvement.

Recent research on inherited metabolic diseases in children

With the improvement in the research level and the diagnosis and treatment technology of inherited metabolic diseases (IMD), the research on pediatric IMD in China has made great progress, but there is still some distance from the international level. Due to the vast territory of China and the uneven distribution of medical resources, the regional characteristics of IMD remain unclear in China, and there are many problems and difficulties in early diagnosis and treatment. Therefore, it is necessary to improve the understanding of pediatric IMD among pediatricians, so as to improve the diagnosis and treatment level, achieve an early identification, diagnosis, and treatment of pediatric IMD, and effectively reduce the fatality and disability rates of children with IMD. This article reviews the research progress of IMD in children in China, and analyzes the features of representative IMDs. Citation:Chinese Journal of Contemporary Pediatrics, 2022, 24(3): 326-331.

[Pre-conception carrier screening for 21 inherited metabolic diseases in a Chinese population]

OBJECTIVE

To determine the carrier rate for 21 inherited metabolic diseases among a Chinese population of childbearing age.

METHODS

A total of 897 unrelated healthy individuals (including 143 couples) were recruited, and DNA was extracted from their peripheral blood samples. Whole exome sequencing (WES) was carried out to screen potential variants among 54 genes associated with 21 inherited metabolic diseases. Pathogenic and likely pathogenic variants and unreported loss-of-function variants were analyzed.

RESULTS

One hundred fourty types of pathogenic/likely pathogenic variants (with an overall number of 183) and unreported loss-of-function variants were detected, which yield a frequency of 0.20 per capita. A husband and wife were both found to carry pathogenic variants of the SLC25A13 gene and have given birth to a healthy baby with the aid of preimplantation genetic diagnosis. The detected variants have involved 40 genes, with the most common ones including ATP7B, SLC25A13, PAH, CBS and MMACHC. Based on the Hardy-Weinberg equilibrium, the incidence of the 21 inherited metabolic diseases in the population was approximately 1/1100, with the five diseases with higher incidence including citrullinemia, methylmalonic acidemia, Wilson disease, glycogen storage disease, and phenylketonuria.

CONCLUSION

This study has preliminarily determined the carrier rate and incidence of 21 inherited metabolic diseases among a Chinese population of childbearing age, which has provided valuable information for the design of neonatal screening program for inherited metabolic diseases. Pre-conception carrier screening can provide an important measure for the prevention of transmission of Mendelian disorders in the population.

Using Informatics to Build a Digital Health Footprint of Patients Living With Inherited Metabolic Disorders Identified by Newborn Screening

Newborn screening is a process identifying people with inherited metabolic disorders (IMDs) at birth, but these patients are often lost to follow-up, and limited data on their long-term needs are available to advocate for policies that will help this vulnerable community. Using informatics best practices, the Medical Nutrition Therapy for Prevention (MNT4P) program and the Public Health Informatics Institute successfully deployed a minimally viable product-that is, the most basic working version that is scalable-allowing for lifelong patient follow-up and outcome and needs tracking, and that can address national data gaps. The new system offers a HIPAA-compliant, efficient record-keeping system that allows data standardization and harmonization. MNT4P staff have transitioned completely away from former manual processes and are relying on this system to log and track patient information. Other programs serving patient populations burdened with rare, marginalized diseases also may benefit from this work.

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.

Tsukushi and TSKU genotype in obesity and related metabolic disorders

PURPOSE

Whether Tsukushi (TSK) can protect against high-fat diet (HFD)-induced obesity and improve glucose metabolism remains controversial. Serum levels of TSK in the population have not been reported until now. We assessed the association among TSK level, TSKU genotype, and metabolic traits in humans.

METHODS

Associations between serum TSK levels and metabolic traits were assessed in 144 Han Chinese individuals. Loci in the TSKU gene region were further genotyped in 11,022 individuals. The association between the loci and serum TSK level was evaluated using the additive genetic model. The association between the loci and their metabolic traits in humans were also verified.

RESULTS

Lower TSK levels were observed in obese subjects than in control subjects (median and interquartile range 17.78:12.07-23.28 vs. 23.81:12.54-34.56, P < 0.05). However, in obese subjects, TSK was positively associated with BMI (β ± SE: 0.63 ± 0.31, P = 0.049), visceral fat area (β ± SE: 12.15 ± 5.94, P = 0.011), and deterioration of glucose metabolism. We found that rs11236956 was associated with TSK level in obese subjects (β 95% CI 0.17, 0.07-0.26; P = 0.0007). There was also a significant association between rs11236956 and metabolic traits in our population.

CONCLUSIONS

Our findings showed that serum TSK levels were associated with metabolic disorders in obese subjects. We also identified rs11236956 to be associated with serum TSK levels in obese subjects and with metabolic disorders in the total population.

Integrative analysis of the plasma proteome and polygenic risk of cardiometabolic diseases

Cardiometabolic diseases are frequently polygenic in architecture, comprising a large number of risk alleles with small effects spread across the genome1-3. Polygenic scores (PGS) aggregate these into a metric representing an individual's genetic predisposition to disease. PGS have shown promise for early risk prediction4-7 and there is an open question as to whether PGS can also be used to understand disease biology8. Here, we demonstrate that cardiometabolic disease PGS can be used to elucidate the proteins underlying disease pathogenesis. In 3,087 healthy individuals, we found that PGS for coronary artery disease, type 2 diabetes, chronic kidney disease and ischaemic stroke are associated with the levels of 49 plasma proteins. Associations were polygenic in architecture, largely independent of cis and trans protein quantitative trait loci and present for proteins without quantitative trait loci. Over a follow-up of 7.7 years, 28 of these proteins associated with future myocardial infarction or type 2 diabetes events, 16 of which were mediators between polygenic risk and incident disease. Twelve of these were druggable targets with therapeutic potential. Our results demonstrate the potential for PGS to uncover causal disease biology and targets with therapeutic potential, including those that may be missed by approaches utilizing information at a single locus.