Inborn errors of metabolism

Urea cycle disorders are a group of inborn errors of metabolism caused by dysfunction of any of the six enzymes or two transport proteins involved in urea biosynthesis. In this paper, we report a patient who presented with neurological dysfunction and coma in the immediate postpartum period. She was misdiagnosed for many years as a case of multiple sclerosis. The importance of reporting this case is to illustrate that the wrong diagnosis of patients as being affected with multiple sclerosis for many years due to magnetic resonance imaging abnormalities rather than the classic relapsing-remitting nature of the disease may lead to catastrophic consequences...

OBJECTIVES: To examine relationships between dietary intake, growth and body composition patterns in patients with inborn errors of intermediary protein metabolism and to determine a safe protein:energy ratio (P:E ratio) associated with optimal growth outcomes. STUDY DESIGN: Retrospective longitudinal data of growth and dietary intake in patients (n = 75) with isovaleric acidemia (IVA; n = 7), methylmalonic acidemia/propionic acidemia (MMA/PA; n = 14), urea cycle defects (UCD; n = 44), classical maple syrup urine disease (MSUD; n = 10) were collected...

Diagnosis and treatment of inborn errors of metabolism (IEM) require the analysis of a variety of metabolites. These compounds are usually quantified by targeted platforms. High resolution mass spectrometry (HRMS) has the potential to detect hundreds to thousands of metabolites simultaneously. A chip-based nanoelectrospray source (chip-based nanoESI) enables the direct infusion of biological samples. Major advantages of this system include high sample throughput, no sample carryover, and low sample consumption...

BACKGROUND AND AIMS: Severe neonatal hypoglycemia (HG) leads to neurologic damage, mental retardation, epilepsy, personality disorders, impaired cardiac performance and muscle weakness. We aimed to assess the clinical characteristics of children with hypoglycemia in a random population of newborns. PATIENTS, METHODS AND RESULTS: We investigated 84 patients (M:F=35:48) born at the University Clinic for Gynecology and Obstetrics in Skopje (hospitalized in the NICU) who were found to have hypoglycemia...

Cerebrotendinous xanthomatosis (CTX) is a rare, autosomal recessive, inborn error of bile acid metabolism characterized by diarrhea in infancy, juvenile cataracts in childhood, tendon xanthomas developing in the second to third decades of life, and progressive neurologic dysfunction in adulthood. The condition is caused by mutations in the CYP27A1 gene that result in decreased production of chenodeoxycholic acid (CDCA) and elevated levels of cholestanol and bile alcohols. We present a 36-year-old male of Han ethnicity who developed xanthomas of his Achilles tendons and suffered neurocognitive declines and gait deterioration in his second decade...

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is a rare inborn error of ketone body synthesis and leucine degradation, caused by mutations in the HMGCL gene. In order to obtain a comprehensive view on this disease, we have collected clinical and biochemical data as well as information on HMGCL mutations of 37 patients (35 families) from metabolic centers in Belgium, Germany, The Netherlands, Switzerland, and Turkey. All patients were symptomatic at some stage with 94% presenting with an acute metabolic decompensation...

Cystathionine β-synthase (CBS) deficiency (Online Mendelian Inheritance in Man [OMIM] 236,200) is an autosomal recessive disorder that is caused by mutations in the CBS gene. It is the most common inborn error of sulfur metabolism and is the cause of classical homocystinuria, a condition characterized by very high levels of plasma total homocysteine and methionine. Although recognized as an inborn error of metabolism over 60years ago, these is still much we do not understand related to how this specific metabolic defect gives rise to its distinct phenotypes...

Metabolomics is a rapidly growing field with potential applications in various disciplines. In particular, metabolomics has received special attention in the discovery of biomarkers and diagnostics. This is largely due to the fact that metabolomics provides critical information related to the downstream products of many cellular and metabolic processes which could provide a snapshot of the health/disease status of a particular tissue or organ. Many of these cellular products eventually find their way to urine; hence, analysis of urine via metabolomics has the potential to yield useful diagnostic and prognostic information...

Two enantiomers of 2-hydroxyglutarate (2HG), L (L2HG) and D (D2HG), are metabolites of unknown function in mammalian cells that were initially associated with separate and rare inborn errors of metabolism resulting in increased urinary excretion of 2HG linked to neurological deficits in children (Chalmers et al., 1980; Duran et al., 1980; Kranendijk et al., 2012). More recently, investigators have shown that D2HG is produced by mutant isocitrate dehydrogenase enzymes associated with a variety of human malignancies, such as acute myeloid leukemia, glioblastoma multiforme, and cholangiocarcinoma (Cairns and Mak, 2013; Dang et al...

BACKGROUND: Primary hyperoxaluria type 2 is a rare monogenic disorder inherited in an autosomal recessive pattern. It results from the absence of the enzyme glyoxylate reductase/hydroxypyruvate reductase (GRHPR). As a consequence of deficient enzyme activity, excessive amounts of oxalate and L-glycerate are excreted in the urine, and are a source for the formation of calcium oxalate stones that result in recurrent nephrolithiasis and less frequently nephrocalcinosis. CASE PRESENTATION: We report a case of a 10-month-old patient diagnosed with urolithiasis...

Glutaric aciduria type I (GA I) is an autosomal recessive inborn error of metabolism caused by a deficiency of the enzyme glutaryl-CoA dehydrogenase. This disorder is characterized by progressive dystonia, choreoathetosis, and dyskinesia. It is often misdiagnosed as athetoid cerebral palsy. Laboratory evaluation usually demonstrates increased urinary excretion of gluataric acid and 3-hydroxyglutaric acid. We report a case of a 7-year-old boy presenting with choreoathetosis and dystonia, mimicking as choreoathetoid cerebral palsy...

Tyrosine levels are abnormally elevated in tissues and body fluids of patients with inborn errors of tyrosine metabolism. Tyrosinemia type II, which is caused by tyrosine aminotransferase deficiency, provokes eyes, skin, and central nervous system disturbances in affected patients. However, the mechanisms of brain damage are still poorly known. Considering that studies have demonstrated that oxidative stress may contribute, along with other mechanisms, to the neurological dysfunction characteristic of hypertyrosinemia, in the present study we investigated the effects of antioxidant treatment (NAC and DFX) on DNA damage and oxidative stress markers induced by chronic administration of L-tyrosine in cerebral cortex, hippocampus, and striatum of rats...

BACKGROUND: Gaucher disease (GD) is an inborn error of metabolism caused by mutations in the gene (GBA) coding for glucocerebrosidase (GCase), inherited in an autosomal recessive pattern. GD patients have up to 9% risk of developing PD. CASE PRESENTATION: We report two patients with GD that developed PD at different disease stages. CONCLUSION: We reviewed the literature on the coexistence of PD and GD and speculate that the severity of symptoms may be related to the type of GBA mutation inherited...

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

Phenylketonuria (PKU) is an inborn error of amino acid metabolism with an autosomal recessive inheritance caused in most cases by mutations in the phenylalanine hydroxylase (PAH) gene. PKU has wide allelic heterogeneity. Here we report a novel heterozygous substitution (c.1223G>T (p.Arg408Leu)) in the PAH gene in an Iranian PKU family. The patient was 19-yr-old female with diagnosis of moderate PKU referred to Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran for genetic counseling/analysis in April 2015...

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Isovaleric acidemia (IVA) is an autosomal recessive inborn error of leucine metabolism. It is caused by a deficiency in the mitochondrial isovaleryl-CoA dehydrogenase (IVD) enzyme. In this study, we investigated eight patients with IVA. The patients diagnoses were confirmed by urinary organic acid analysis and the blood C5-Carnitine value. A molecular genetic analysis of the IVD gene revealed nine different variants: five were missense variants (c.1193G>A; p. R398Q, c.1207T>A; p. Y403N, c.872C>T; p...

Hypophosphatasia is the inborn error of metabolism that is characterized by low serum alkaline-phosphatase activity, due to loss-of-function mutations within the gene for tissuenonspecific isoenzyme of alkaline phosphatase [TNSALP]. The manifestations of hypophosphatasia range from neonatal death with almost no skeletal mineralization to dental problems in adults without any bone symptoms. There are no case reports of infantile hypophosphatasia in Israel. The existence of enzymatic replacement treatment for this disease makes it important to diagnose this problem as soon as possible...

The urea cycle disorder carbamoyl phosphate synthetase I deficiency is an important differential diagnosis in the encephalopathic neonate. This intoxication type inborn error of metabolism often leads to neonatal death or severe and irreversible damage of the central nervous system, even despite appropriate treatment. Timely diagnosis is crucial, but can be difficult on routine metabolite level. Here, we report ten neonates from eight families (finally) diagnosed with CPS1 deficiency at three tertiary metabolic centres...

OBJECTIVE: Psychotic disorders in childhood and early adolescence often progress to chronic schizophrenia, but in many cases there are diagnosable medical and genetic causes or risk factors. We reviewed our clinical experience and the relevant literature to identify these factors and to define their clinical features, appropriate work-up and treatment. METHOD: We reviewed the results of comprehensive medical evaluations of 160 psychotic children and adolescents in our center...