Acute intoxication‐type inborn errors of metabolism (IT‐IEM) such as urea cycle disorders and non‐acute IT‐IEM such as phenylketonuria have a major impact on paediatric patients’ life. Patients have to adhere to a strict diet but may face neurocognitive impairment and ‐in acute diseases‐ metabolic decompensations nevertheless. Research on the subjective burden of IT‐IEM remains sparse. Studies with

Metabolic epilepsies arise in the context of rare inborn errors of metabolism (IEM), notably glucose transporter type 1 deficiency syndrome, succinic semialdehyde dehydrogenase deficiency, pyruvate dehydrogenase complex deficiency, nonketotic hyperglycinemia, and mitochondrial cytopathies. A common feature of these disorders is impaired bioenergetics, which through incompletely defined mechanisms result

Glycine abundance is modulated in a tissue‐specific manner by use in biosynthetic reactions, catabolism by the glycine cleavage system (GCS), and excretion via glycine conjugation. Dysregulation of glycine metabolism is associated with multiple disorders including epilepsy, developmental delay, and birth defects. Mutation of the GCS component glycine decarboxylase (GLDC) in non‐ketotic hyperglycinemia

Mitochondrial Neurogastrointestinal Encephalomyopathy (MNGIE) is a rare autosomal recessive disease caused by TYMP mutations and thymidine phosphorylase (TP) deficiency. Thymidine and deoxyuridine accumulate impairing the mitochondrial DNA maintenance and integrity. Clinically, patients show severe and progressive gastrointestinal and neurological manifestations. The onset typically occurs in the second

Mannose phosphate isomerase MPI‐CDG (formerly CDG‐1b) is a potentially fatal inherited metabolic disease which is readily treatable with oral D‐mannose. We retrospectively reviewed long‐term outcomes of patients with MPI‐CDG, all but one of whom were treated with D‐mannose. Clinical, biological, and histological data were reviewed at diagnosis and on D‐mannose treatment. Nine patients were diagnosed

Bikunin (Bkn) isoforms are serum chondroitin sulfate (CS) proteoglycans synthesized by the liver. They include two light forms, that is, the Bkn core protein and the Bkn linked to the CS chain (urinary trypsin inhibitor [UTI]), and two heavy forms, that is, pro‐α‐trypsin inhibitor and inter‐α‐trypsin inhibitor, corresponding to UTI esterified by one or two heavy chains glycoproteins, respectively.

Asparagine‐linked glycosylation 13 homolog (ALG13 ) encodes a nonredundant, highly conserved, X‐linked uridine diphosphate (UDP)‐N ‐acetylglucosaminyltransferase required for the synthesis of lipid linked oligosaccharide precursor and proper N‐linked glycosylation. De novo variants in ALG13 underlie a form of early infantile epileptic encephalopathy known as EIEE36, but given its essential role in

Long‐term outcome is postulated to be different in isolated methylmalonic aciduria caused by mutations in the MMAA gene (cblA type) compared with methylmalonyl‐CoA mutase deficiency (mut ), but case definition was previously difficult.

Anaplerotic odd‐chain fatty acid supplementation has been suggested as an approach to replenish citric acid cycle intermediate (CACi) pools and facilitate adenosine triphosphate (ATP) production in subjects with long‐chain fatty acid oxidation disorders, but the evidence that cellular CACi depletion exists and that repletion occurs following anaplerotic substrate supplementation is limited. We exercised

Multiple sulfatase deficiency (MSD) is an ultra‐rare neurodegenerative disorder caused by pathogenic variants in SUMF1 . This gene encodes formylglycine‐generating enzyme (FGE), a protein required for sulfatase activation. The clinical course of MSD results from additive effect of each sulfatase deficiency, including metachromatic leukodystrophy (MLD), several mucopolysaccharidoses (MPS II, IIIA, IIID

Galactosemia is a rare, treatable hereditary disorder of carbohydrate metabolism. We investigated the etiology of decreased GALT enzyme activity in a cohort of newborns referred by the Florida Newborn Screening Program with no detectable GALT variants in diagnostic molecular tests. Six affected individuals from four families with Guatemalan heritage were include. GALT enzyme activity ranged from 20%

We investigated seven children from six families to expand the phenotypic spectrum associated with an early infantile epileptic encephalopathy caused by biallelic pathogenic variants in the phosphatidylinositol glycan anchor biosynthesis class Q (PIGQ ) gene. The affected children were all identified by clinical or research exome sequencing. Clinical data, including EEGs and MRIs, was comprehensively

Classic galactosemia (OMIM# 230400) is an autosomal recessive disorder due to galactose‐1‐phosphate uridyltransferase deficiency. Newborn screening and prompt treatment with a galactose‐free diet prevent the severe consequences of galactosemia, but clinical outcomes remain suboptimal. Five men and five women with classic galactosemia (mean age = 27.2 ± 5.47 years) received comprehensive neurological

Post‐translational protein modifications derived from metabolic intermediates, such as acyl‐CoAs, have been shown to regulate mitochondrial function. Patients with an inborn a genetic defect in the propionyl‐CoA carboxylase (PCC) gene clinically present symptoms related to mitochondrial disorders and are characterised by decreased mitochondrial respiration. Since propionyl‐CoA accumulates in PCC deficient

Citrin deficiency is a hereditary disorder caused by SLC25A13 mutations and manifests as neonatal intrahepatic cholestasis (NICCD), failure to thrive and dyslipidemia (FTTDCD), and adult‐onset type II citrullinemia (CTLN2). Citrin is a component of the malate‐aspartate nicotinamide adenine dinucleotide hydrogen (NADH) shuttle, an essential shuttle for hepatic glycolysis. Hepatic glycolysis and the

Despite a wide clinical spectrum, the adult form of Pompe disease is the most common one, and represents more than 90% of diagnosed patients in France. Since the marketing of enzyme replacement therapy (alglucosidase alfa, Myozyme), all reports to date in adults demonstrated an improvement of the walking distance, and a trend toward stabilization of respiratory function, but the majority of these studies

Glutaric aciduria type 1 (GA1) is an inborn error of lysine degradation characterized by acute encephalopathy that is caused by toxic accumulation of lysine degradation intermediates. We investigated the efficacy of substrate reduction through inhibition of 2‐aminoadipic semialdehyde synthase (AASS), an enzyme upstream of the defective glutaryl‐CoA dehydrogenase (GCDH), in a cell line and mouse model

Adult‐onset non‐cirrhotic hyperammonemia (NCH) is poorly understood and has a high morbidity and mortality. To elucidate the etiology and management of NCH we performed a retrospective analysis of 23 adults (median age 51) with NCH treated between 2014 and 2020 at two academic medical centers. Hyperammonemia was diagnosed in all cases during the evaluation of altered mental status, with 22% presenting

Multiple Sulfatase Deficiency (MSD, MIM#272200) is an ultra‐rare lysosomal storage disorder arising from mutations in the SUMF1 gene, which encodes the formylglycine‐generating enzyme (FGE). FGE is necessary for the activation of sulfatases, a family of enzymes that are involved in the degradation of sulfated substrates such as glycosaminoglycans and sulfolipids. SUMF1 mutations lead to functionally

Genetic therapies based on gene addition have witnessed a variety of clinical successes and the first therapeutic products have been approved for clinical use. Moreover, innovative gene editing techniques are starting to offer new opportunities in which the mutations that underlie genetic diseases can be directly corrected in afflicted somatic cells. The toolboxes underpinning these DNA modifying technologies

Phosphoglucomutase 1 (PGM1) deficiency is a rare genetic disorder that affects glycogen metabolism, glycolysis, and protein glycosylation. Previously known as GSD XIV, it was recently reclassified as a congenital disorder of glycosylation, PGM1‐CDG. PGM1‐CDG usually manifests as a multisystem disease. Most patients present as infants with cleft palate, liver function abnormalities and hypoglycemia

Methylcitric acid (MCA) analysis has been mainly utilized for the diagnosis of propionate disorders or as a second tier test in newborn screening, but its utility for patients monitoring still need to be established. We explored the potential contribution of MCA in the long‐term management of organic acidurias.

Congenital disorders of glycosylation (CDG) are a rapidly expanding group of rare genetic defects in glycosylation. In a novel CDG subgroup of vacuolar‐ATPase (V‐ATPase) assembly defects, various degrees of hepatic injury have been described, including end‐stage liver disease. However, the CDG diagnostic workflow can be complex as liver disease per se may be associated with abnormal glycosylation.

The neurological phenotype of 3‐hydroxyisobutyryl‐CoA hydrolase (HIBCH) and short‐chain enoyl‐CoA hydratase (SCEH) defects is expanding and natural history studies are necessary to improve clinical management.

(+)‐Epicatechin (EPI) induces mitochondrial biogenesis and antioxidant metabolism in muscle fibers and neurons. We aimed to evaluate safety and efficacy of (+)‐EPI in pediatric subjects with Friedreich's Ataxia (FRDA).

At the time of writing, severe Covid‐19 disease has been responsible for 383 000 deaths worldwide (Johns Hopkins data). Most deaths occur in the <10% of infected individuals that develop respiratory failure.1 This is caused by bilateral interstitial pneumonia and acute respiratory distress syndrome and leads to dependence on mechanical ventilation.2 The pathogenesis of the pneumonia is poorly understood

The aim of this study was to compare the long‐term outcome of classic infantile Pompe patients treated with 20 mg/kg alglucosidase alfa every other week (eow) to those treated with 40 mg/kg/week, and to study the additional effect of immunomodulation. Six patients received 20 mg/kg eow and twelve 40 mg/kg/week. Five patients were cross‐reactive immunologic material (CRIM)‐negative, two in the 20 mg

5‐Amino‐4‐imidazolecarboxamide‐ribosiduria (AICA)‐ribosiduria is an exceedingly rare autosomal recessive condition resulting from the disruption of the bifunctional purine biosynthesis protein PURH (ATIC), which catalyzes the last two steps of de novo purine synthesis. It is characterized biochemically by the accumulation of AICA‐riboside in urine. AICA‐ribosiduria had been reported in only one individual

Hearing loss is frequently seen in mucopolysaccharidoses (MPS) patients. Although hematopoietic cell transplantation (HCT) increases overall survival, disease progression is observed in certain tissues. This study describes the course of hearing loss (HL) over time in transplanted MPS patients. Transplanted MPS patients between 2003 and 2018 were included and received yearly audiological evaluation

Our daughter Nina Contreras D'Agosto is a half‐Spanish, half‐Italian 30‐month‐old baby girl. She is also known as Nina, the Von Gierke's Warrior, and she is unique. Not only because she lives with Glycogen Storage Disease (GSD) type 1b—an inherited metabolic condition that affects one out of 1 million people—but also because during her short life, and despite all her health‐related challenges, she

Sjögren‐Larsson syndrome (SLS) is a rare neurometabolic syndrome caused by deficient fatty aldehyde dehydrogenase. Patients exhibit intellectual disability, spastic paraplegia, and ichthyosis. The accumulation of fatty alcohols and fatty aldehydes has been demonstrated in plasma and skin but never in brain. Brain magnetic resonance imaging and spectroscopy studies, however, have shown an abundant lipid

Primary mitochondrial diseases represent some of the most common and severe inherited metabolic disorders, affecting approximately 1 in 4300 live births. The clinical and molecular diversity typified by mitochondrial diseases has contributed to the lack of licensed disease‐modifying therapies available. Management for the majority of patients is primarily supportive. The failure of clinical trials

Glycogen storage disease type Ia (GSD‐Ia) is an inherited metabolic disease caused by a deficiency in glucose‐6‐phosphatase‐α (G6Pase‐α or G6PC) which plays a critical role in blood glucose homeostasis by catalyzing the hydrolysis of glucose‐6‐phosphate (G6P) to glucose and phosphate in the terminal step of glycogenolysis and gluconeogenesis. Patients with GSD‐Ia manifest life‐threatening fasting hypoglycemia

Inherited cutis laxa, or inelastic, sagging skin is a genetic condition of premature and generalised connective tissue ageing, affecting various elastic components of the extracellular matrix. Several cutis laxa syndromes are inborn errors of metabolism and lead to severe neurological symptoms. In a patient with cutis laxa, a choreoathetoid movement disorder, dysmorphic features and intellectual disability

Patients with Fabry disease (FD) have a high prevalence of depressive symptoms and can suffer from cognitive impairment, negatively affecting their life. The course of cognitive functioning and depressive symptoms in FD is unknown. The aim of this prospective cohort study was to describe changes in cognitive functioning and depressive symptoms and to identify related variables in patients with FD over

2‐Oxoglutarate dehydrogenase (OGDH) is a rate‐limiting enzyme in the mitochondrial TCA cycle, encoded by the OGDH gene. α‐Ketoglutarate dehydrogenase (OGDH) deficiency was previously reported in association with developmental delay, hypotonia, and movement disorders and metabolic decompensation, with no genetic data provided. Using whole exome sequencing, we identified two individuals carrying a homozygous

GM1‐gangliosidosis is a rare autosomal recessive lysosomal storage disease caused by deficiency of β‐galactosidase (GLB1). Newborn screening (NBS) may be warranted in the near future given the initiation of a number of gene therapy clinical trials. Here we report a tandem mass spectrometry (MS/MS) enzymatic assay of GLB1 using dried blood spots (DBS), and the demonstration that GLB1 activities in newborn

Cardiomyopathy can be a severe complication in patients with long‐chain fatty acid β‐oxidation disorders (LCFAOD), particularly during episodes of metabolic derangement. It is unknown whether latent cardiac abnormalities exist in adult patients. To investigate cardiac involvement in LCFAOD, we used proton magnetic resonance imaging (MRI) and spectroscopy (1H‐MRS) to quantify heart function, myocardial

Nucleotide sugars (NS) are fundamental molecules in life and play a key role in glycosylation reactions and signal conduction. Several pathways are involved in the synthesis of NS. The Leloir pathway, the main pathway for galactose metabolism, is crucial for production of uridine diphosphate (UDP)‐glucose and UDP‐galactose. The most common metabolic disease affecting this pathway is galactose‐1‐phosphate

Plasmalogens (Pls) are a class of membrane phospholipids which serve a number of essential biological functions. Deficiency of Pls is associated with common disorders such as Alzheimer's disease or ischemic heart disease. A complete lack of Pls due to genetically determined defective biosynthesis gives rise to rhizomelic chondrodysplasia punctata (RCDP), characterized by a number of severe disabling

Organic acidurias (OADs) comprise a biochemically defined group of inherited metabolic diseases. Increasing awareness, reliable diagnostic work-up, newborn screening programs for some OADs, optimized neonatal and intensive care, and the development of evidence-based recommendations have improved neonatal survival and short-term outcome of affected individuals. However, chronic progression of organ

Aromatic l-amino acid decarboxylase deficiency (AADCD) is a rare, autosomal recessive neurodevelopmental disorder characterized by impaired synthesis of dopamine, noradrenaline, adrenaline and serotonin, leading to a complex syndrome of motor, behavioral, and autonomic symptoms. This retrospective study assessed the symptoms and developmental outcome of a large international cohort of patients with

Timely diagnosis is essential for patients with neurometabolic disorders to enable targeted treatment. Next-Generation Metabolic Screening (NGMS) allows for simultaneous screening of multiple diseases and yields a holistic view of disturbed metabolic pathways. We applied this technique to define a cerebrospinal fluid (CSF) reference metabolome and validated our approach with patients with known neurometabolic

The transmembrane domain recognition complex (TRC) targets cytoplasmic C‐terminal tail‐anchored (TA) proteins to their respective membranes in the endoplasmic reticulum (ER), Golgi, and mitochondria. It is composed of three proteins, GET4, BAG6, and GET5. We identified an individual with compound heterozygous missense variants (p.Arg122His, p.Ile279Met) in GET4 that reduced all three TRC proteins by

The identification of pathogenic GLA variants plays a central role in the establishment of a definite Fabry disease (FD) diagnosis. We aimed to review and interpret the published data on the p.Asp313Tyr (p.D313Y) variant pathogenicity and clinical relevance. We performed a systematic review of peer-reviewed publications and case-reports on individuals and populations harbouring the p.Asp313Tyr variant

Many similarities between tryptophan (Trp) and phenylalanine (Phe) metabolisms exist. It is possible that a modification of Trp metabolism might be seen in phenylketonuria (PKU). As some of these metabolites have neuroactive properties, they should be consider in neurological impairment seen in this pathology and not totally explained by blood Phe concentrations. One hundred and fifty‐one adult PKU

Antisense oligonucleotide (AON) therapies involve short strands of modified nucleotides that target RNA in a sequence‐specific manner, inducing targeted protein knockdown or restoration. Currently, 10 AON therapies have been approved in the United States and Europe. Nucleotides are chemically modified to protect AONs from degradation, enhance bioavailability and increase RNA affinity. Whereas single

Miglustat has been indicated for the treatment of Niemann-Pick disease type C (NP-C) since 2009. The aim of this observational study was to assess the effect of miglustat on long-term survival of patients with NP-C. Data for 789 patients from five large national cohorts and from the NPC Registry were collected and combined. Miglustat-treated and untreated patients overall and within sub-groups according

Correction to: Plasma FGF‐21 and GDF‐15 are elevated in different inherited metabolic diseases and are not diagnostic for mitochondrial disorders. In this paper,1 several authors have incorrect additional affiliations. Here is the correct list of authors with their affiliations: Tsygankova PG1, Itkis YS1, Krylova TD1, Kurkina MV1, Bychkov IO1, Ilyushkina AA1, Zabnenkova VV2, Mikhaylova SV3, Pechatnikova

Sphingosine-1-phosphate (S1P) lyase is a vitamin B6-dependent enzyme that degrades sphingosine-1-phosphate in the final step of sphingolipid metabolism. In 2017, a new inherited disorder was described caused by mutations in SGPL1, which encodes sphingosine phosphate lyase (SPL). This condition is referred to as SPL insufficiency syndrome (SPLIS) or alternatively as nephrotic syndrome type 14 (NPHS14)

Infantile neuronal ceroid lipofuscinosis (INCL) is a devastating neurodegenerative lysosomal storage disease (LSD) caused by inactivating mutations in the CLN1 gene. CLN1 encodes palmitoyl-protein thioesterase-1 (PPT1), a lysosomal enzyme that catalyzes the deacylation of S-palmitoylated proteins to facilitate their degradation and clearance by lysosomal hydrolases. Despite the discovery more than

d-3-Hydroxy-n-butyrate dehydrogenase (BDH1; EC 1.1.1.30), encoded by BDH1, catalyzes the reversible reduction of acetoacetate (AcAc) to 3-hydroxybutyrate (3HB). BDH1 is the last enzyme of hepatic ketogenesis and the first enzyme of ketolysis. The hereditary deficiency of BDH1 has not yet been described in humans. To define the features of BDH1 deficiency in a mammalian model, we generated Bdh1-deficient

Newborn screening (NBS) programmes utilise information on a variety of clinical variables such as gestational age, sex, and birth weight to reduce false-positive screens for inborn metabolic disorders. Here we study the influence of ethnicity on metabolic marker levels in a diverse newborn population. NBS data from screen-negative singleton babies (n = 100 000) were analysed, which included blood metabolic

In this article, we report four new patients, from three kindreds, with pathogenic variants in RBCK1 and a multisystem disorder characterised by widespread polyglucosan storage. We describe the clinical presentation of progressive skeletal and cardiac myopathy, combined immunodeficiencies and auto‐inflammation, illustrate in detail the histopathological findings in multiple tissue types, and report

Hydrogen sulfide, a signaling molecule formed mainly from cysteine, is catabolized by sulfide:quinone oxidoreductase (gene SQOR). Toxic hydrogen sulfide exposure inhibits complex IV. We describe children of two families with pathogenic variants in SQOR. Exome sequencing identified variants; SQOR enzyme activity was measured spectrophotometrically, protein levels evaluated by western blotting, and mitochondrial

BACKGROUND Classical organic acidemias (OAs) result from defective mitochondrial catabolism of branched-chain amino acids (BCAAs). Abnormal mitochondrial function relates to oxidative stress, ectopic lipids and insulin resistance (IR). We investigated whether genetically impaired function of mitochondrial BCAA catabolism associates with cardiometabolic risk factors, altered liver and muscle energy

Neuronopathic Gaucher disease (nGD) has a very wide clinical and genotypic spectrum. However, there is no consensus definition of nGD, including no description of how best to diagnostically separate the acute form—Gaucher type 2—from the subacute or chronic form—Gaucher type 3. In this article, we define the various forms of Gaucher disease with particular emphasis on the presence of gaze palsy in

Patients with lysine‐related inborn errors of metabolism (pyridoxine‐dependent epilepsy [PDE] and glutaric aciduria type 1 [GA1]), follow a lysine‐restricted diet with arginine‐fortified lysine‐free amino acid formula and additional oral arginine supplementation as a newer therapy for PDE. The rationale of arginine supplementation is based on arginine's ability to compete with lysine transport across

BACKGROUND For over two decades, Nitisinone (NTBC) has been successfully used to manipulate the tyrosine degradation pathway and save the lives of many children with hereditary tyrosinaemia type1 (HT1). More recently, NTBC has been used to halt homogentisic acid accumulation in alkaptonuria (AKU) with evidence suggesting its efficacy as a disease modifying agent. NTBC induced hypertyrosinemia has been