Low C0 and normal C16 and C18:1 masking the diagnosis of carnitine palmitoyltransferase II deficiency including a novel CPT2 variant: A case report.

The cases were a pair of siblings with a carnitine palmitoyltransferase (CPT2) deficiency detected by tandem mass spectrometry. Their C16 and C18:1 levels were both within the normal range, while C0 was low, and the (C16+C18:1)/C2 ratio was high. Following genetic testing, a novel CPT2 gene mutation was identified in both patients. The male patient had a normal growth rate during 5 years of follow-up after treatment. By contrast, the female patient did not take l-carnitine supplements and died after an infectious disease-associated illness when she was 1 year old. These data emphasize the need to raise awareness about CPT2 deficiency so as to correctly diagnose and accurately manage the disease.

Inborn errors of bile acid metabolism in Japan.

Bile acids are a category of steroids biosynthesized from cholesterol in the liver. Inborn errors of their metabolism are inherited in an autosomal recessive manner, resulting in enzyme deficiencies affecting the bile acid biosynthetic pathway. These defects in the pathway cause accumulation of unusual bile acids or bile alcohols. Unusual bile acids are highly cytotoxic, causing injury to the liver. These unusual bile acids damage hepatocytes, resulting in cholestatic liver injury beginning in infancy. Except for cerebrotendinous xanthomatosis and some secondary defects, various inborn errors of bile acid metabolism (IEBAM) have been reported from Japan, affecting eight patients including three with 3ß-hydroxy-Δ5 -C27 -steroid dehydrogenase/isomerase deficiency, three with Δ4 -3-oxosteroid 5ß-reductase deficiency, one with oxysterol 7α-hydroxylase deficiency, and one with bile acid-CoA: amino acid N-acyltransferase deficiency. Distinctive laboratory findings in patients with 3ß-hydroxy-Δ5 -C27 -steroid dehydrogenase/isomerase deficiency, Δ4 -3-oxosteroid 5ß-reductase deficiency, and oxysterol 7α-hydroxylase deficiency include normal serum γ-glutamyltransferase and total bile acids concentrations despite presence of cholestasis (elevated serum direct bilirubin) from infancy. Pediatricians and pediatric surgeons who suspect a case of IEBAM should obtain urinary and serum bile acid analyses using gas or liquid chromatography-mass spectrometry as well as genetic analyses. Available treatments include oral cholic acid, chenodeoxycholic acid, glycocholic acid, and ursodeoxycholic acid; fat-soluble vitamin supplementation; and liver transplantation. Early diagnosis and treatment can offer a good outcome.

Crohn's Disease Presenting as Metabolic Myopathy: A Case Report.

Myopathies associated with systemic diseases results from several different disease processes. Myopathy as the initial presenting symptom in Crohn's disease is a rare presentation. We report a 20-yearr-old lady who presented with a painful proximal myopathy. On examination, she was malnourished with pallor, angular cheilitis, Bitots spots, and bilateral pitting pedal edema. Laboratory evaluation showed iron deficiency anemia, hypoalbuminemia, and very low vitamin D levels with elevated creatine phosphokinase levels. A possibility of osteomalacic metabolic myopathy due to vitamin D deficiency was considered. The malabsorption workup was negative. A colonoscopic biopsy showed noncaseating granulomatous inflammation suggestive of Crohn's disease. With supplementary therapy and specific treatment, she was asymptomatic at 6-months follow-up with no residual neurological deficits. A detailed history and an algorithmic approach will be very useful in making the differential diagnosis in any patient presenting with muscle weakness in myopathy associated with systemic illness.

Insights into National Laboratory Newborn Screening and Future Prospects.

Newborn screening (NBS) is a group of tests that check all newborns for certain rare conditions, covering several genetic or metabolic disorders. The laboratory NBS is performed through blood testing. However, the conditions that newborn babies are screened for vary from one country to another. Since NBS began in the 1960s, technological advances have enabled its expansion to include an increasing number of disorders, and there is a national trend to further expand the NBS program. The use of mass spectrometry (MS) for the diagnosis of inborn errors of metabolism (IEM) obviously helps in the expansion of the screening panels. This technology allows the detection of different metabolic disorders at one run, replacing the use of traditional techniques. Analysis of the targeted pathogenic gene variant is a routine application in the molecular techniques for the NBS program as a confirmatory testing to the positive laboratory screening results. Recently, a lot of molecular investigations, such as next generation sequencing (NGS), have been introduced in the routine NBS program. Nowadays, NGS techniques are widely used in the diagnosis of IMD where its results are rapid, confirmed and reliable, but, due to its uncertainties and the nature of IEM, it necessitates a holistic approach for diagnosis. However, various characteristics found in NGS make it a potentially powerful tool for NBS. A range of disorders can be analyzed with a single assay directly, and samples can reduce costs and can largely be automated. For the implementation of a robust technology such as NGS in a mass NBS program, the main focus should not be just technologically biased; it should also be tested for its long- and short-term impact on the family and the child. The crucial question here is whether large-scale genomic sequencing can provide useful medical information beyond what current NBS is already providing and at what economical and emotional cost? Currently, the topic of newborn genome sequencing as a public health initiative remains argumentative. Thus, this article seeks the answer to the question: NGS for newborn screening- are we there yet?

A novel metabolic disorder in the degradation pathway of endogenous methanol due to a mutation in the gene of alcohol dehydrogenase.

BACKGROUND: A small amount of methanol is produced endogenously in the human body but it is efficiently metabolized by alcohol dehydrogenase (ADH) and other enzymes, and the products eliminated without harm. In this study, we present a new entity of inborn error of methanol metabolism due to a mutation in the ADH1C gene coding for the γ subunit that is part of several ADH isoenzymes. RESULTS: This disorder was discovered in an 11.58-year-old boy. During one 9-month hospital admission, he had periods of 1-4 days during which he was comatose, and between these periods he was sometimes verbose and euphoric, and had ataxia, dysarthria. Following hemodialysis treatments, he became conscious and appeared healthy. Organ evaluations and his laboratory tests were normal. Toxicological evaluation of his blood showed a high methanol level [12.2 mg/dL (3.8 mmol/L), normal range up to 3.5 mg/dL (1.09 mmol/L) while the formaldehyde level was undetectable. The finding of liver function tests that were within normal limits, coupled with a normal eye examination and size of the liver, elevated blood methanol levels and an undetectable formaldehyde level, suggested ADH insufficiency. Adding zinc to the drug regimen 15 mg/daily dramatically reduced the patient's methanol level and alleviated the abnormal symptoms. When zinc supplementation was discontinued, the patient relapsed into a coma and hemodialysis was once again required. A homozygous mutation in ADH1C gene located at exon 3 was found, and both parents were heterozygous for this mutation. CONCLUSION: Accumulation of methanol due to mutation in ADH1C gene may result in drunkenness and ataxia, and leads to coma. This condition can be successfully treated with zinc supplementation as the cofactor of ADH.

A holistic approach to the patients/ Families with inborn errors of metabolism.

BACKGROUND: Diagnosis, treatment, and care of inborn errors of metabolism require well organized interdisciplinary teams. Holistic approaches comprise the system of all elements and relations between elements necessary for an optimal function of the system. METHODS: Following the rule "structure follows function" based on scientific, academic, and clinical experience the elements of the system providing diagnosis, treatment, and care for inborn errors of metabolism are defined and described. RESULTS: A holistic approach to inborn errors of metabolism comprising 10 elements is suggested, established, and controlled by an interdisciplinary metabolic team organized as a disease, and a case management program based on evidence-based guidelines is suggested. Quality assurance and quality control will not only improve the treatment of the individual but also the health system. CONCLUSION: The holistic approach is a joint project of the team of health care professionals and the person with a condition, allowing them to see the patient's individual medical, behavioral, social, legal, and economic context. For practical, technical, and economic reasons this will only be possible in centers caring for a critical number of individuals.

Diagnostic challenges in metabolic myopathies.

INTRODUCTION: Metabolic myopathies comprise a clinically etiological diverse group of disorders caused by defects in cellular energy metabolism including the breakdown of carbohydrates and fatty acids, which include glycogen storage diseases and fatty acid oxidation disorders. Their wide clinical spectrum ranges from infantile severe multisystemic disorders to adult-onset myopathies. To suspect in adults these disorders, clinical features such as exercise intolerance and recurrent myoglobinuria need investigation while another group presents fixed weakness and cardiomyopathy as a clinical pattern. AREAS COVERED: In metabolic myopathies, clinical manifestations are important to guide diagnostic tests used in order to lead to the correct diagnosis. The authors searched in literature the most recent techniques developed. The authors present an overview of the most common phenotypes of Pompe disease and what is currently known about the mechanism of ERT treatment. The most common disorders of lipid metabolism are overviewed, with their possible dietary or supplementary treatments. EXPERT COMMENTARY: The clinical suspicion is the clue to conduct in-depth investigations in suspected cases of metabolic myopathies that lead to the final diagnosis with biochemical molecular studies and often nowadays by the use of Next Generation Sequencing (NGS) to determine gene mutations.

Medical Foods for Inborn Errors of Metabolism: History, Current Status, and Critical Need.

Successful intervention for inborn errors of metabolism (IEMs) is a triumph of modern medicine. For many of these conditions, medical foods are the cornerstone of therapy and the only effective interventions preventing disability or death. Medical foods are designed for patients with limited or impaired capacity to ingest, digest, absorb, or metabolize ordinary foods or nutrients, whereby dietary management cannot be achieved by modification of the normal diet alone. In the United States today, access to medical foods is not ensured for many individuals who are affected despite their proven efficacy in the treatment of IEMs, their universal use as the mainstay of IEM management, the endorsement of their use by professional medical organizations, and the obvious desire of families for effective care. Medical foods are not sufficiently covered by many health insurance plans in the United States and, without insurance coverage, many families cannot afford their high cost. In this review, we outline the history of medical foods, define their medical necessity, discuss the barriers to access and reimbursement resulting from the regulatory status of medical foods, and summarize previous efforts to improve access. The Advisory Committee on Heritable Disorders in Newborns and Children asserts that it is time to provide stable and affordable access to the effective management required for optimal outcomes through the life span of patients affected with IEMs. Medical foods as defined by the US Food and Drug Administration should be covered as required medical benefits for persons of all ages diagnosed with an IEM.

Transcobalamin deficiency: vitamin B12 deficiency with normal serum B12 levels.

Transcobalamin (TC) deficiency is a rare autosomal recessive inborn error of cobalamin transport which clinically manifests in early infancy. We describe a child with TC deficiency who presented with classical clinical and lab stigmata of inborn error of vitamin B12 metabolism except normal serum B12 levels. He was started on empirical parenteral cobalamin supplements at 2 months of age; however, the definitive diagnosis could only be established at 6 years of age when a genetic evaluation revealed homozygous nonsense variation in exon 8 of the TCN2 gene (chr22:g.31019043C>T).

Phenotype of carnitine palmitoyltransferase II (CPT II) deficiency: A questionnaire-based survey.

Wide spectrums of symptoms besides muscle weakness, different triggering factors and varied muscles involvement are associated with CPT II deficiency. However, systematic clinical characterization of CPT II deficiency is not known. A Questionnaire-based retrospective study on 13 biochemically and genetically confirmed CPT II deficient patients was performed to analyze these aspects. Attacks of myalgia (13/13 patients), weakness (13/13) and rhabdomyolysis (10/13 patients) were most frequently reported. The number of attacks ranged from 1 to 85/year. Common triggers were exercise (13/13), fasting (13/13), cold (12/13) and infections (12/13). Exercise lasting from 15 to 60 min was sufficient for attacks in 9/13 patients, 1-4 h in 3/13 patients and more than 4 h in 1/13 patient. 2/13 patients required dialysis. Limb muscles were affected slightly more often than other muscles. Mean intensity of pain in visual analogue scale (VAS) during regular attack was 4.77 (±1.36). Frequency and severity of attacks did not increase during the course of disease in 10/13 patients. 7/13 patients quit sports after the symptoms emerged. 3/13 patients changed their profession permanently. Increased number of attacks were positively correlated with higher BMI (P = 0.05). Body rest, carbohydrate-rich nutrients and fluid-supplement mitigated the pain. After the first attack [Mean: 9.7 (±4.46) years], diagnosis took an average of 26.7 (± 13.06) years. In myopathic CPT II deficiency, frequencies of attacks are highly variable. Generally, the myopathic form is a mild form. However, severe patients requiring dialysis due to kidney failure could be present. Individuals with higher BMI are at risk of developing more frequent attacks.

Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System.

Fatty acid oxidation disorders (FAODs) and carnitine shuttling defects are inborn errors of energy metabolism with associated mortality and morbidity due to cardiomyopathy, exercise intolerance, rhabdomyolysis, and liver disease with physiologic stress. Hypoglycemia is characteristically hypoketotic. Lactic acidemia and hyperammonemia may occur during decompensation. Recurrent rhabdomyolysis is debilitating. Expanded newborn screening can detect most of these disorders, allowing early, presymptomatic treatment. Treatment includes avoiding fasting and sustained extraneous exercise and providing high-calorie hydration during illness to prevent lipolysis, and medium-chain triglyceride oil supplementation in long-chain FAODs. Carnitine supplementation may be helpful. However, conventional treatment does not prevent all symptoms.

Consensus recommendations for the diagnosis, treatment and follow-up of inherited methylation disorders.

Inherited methylation disorders are a group of rarely reported, probably largely underdiagnosed disorders affecting transmethylation processes in the metabolic pathway between methionine and homocysteine. These are methionine adenosyltransferase I/III, glycine N-methyltransferase, S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. This paper provides the first consensus recommendations for the diagnosis and management of methylation disorders. Following search of the literature and evaluation according to the SIGN-methodology of all reported patients with methylation defects, graded recommendations are provided in a structured way comprising diagnosis (clinical presentation, biochemical abnormalities, differential diagnosis, newborn screening, prenatal diagnosis), therapy and follow-up. Methylation disorders predominantly affect the liver, central nervous system and muscles, but clinical presentation can vary considerably between and within disorders. Although isolated hypermethioninemia is the biochemical hallmark of this group of disorders, it is not always present, especially in early infancy. Plasma S-adenosylmethionine and S-adenosylhomocysteine are key metabolites for the biochemical clarification of isolated hypermethioninemia. Mild hyperhomocysteinemia can be present in all methylation disorders. Methylation disorders do not qualify as primary targets of newborn screening. A low-methionine diet can be beneficial in patients with methionine adenosyltransferase I/III deficiency if plasma methionine concentrations exceed 800 µmol/L. There is some evidence that this diet may also be beneficial in patients with S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. S-adenosylmethionine supplementation may be useful in patients with methionine adenosyltransferase I/III deficiency. Recommendations given in this article are based on general principles and in practice should be adjusted individually according to patient's age, severity of the disease, clinical and laboratory findings.

Primary Carnitine Deficiency and Newborn Screening for Disorders of the Carnitine Cycle.

Carnitine is needed for transfer of long-chain fatty acids across the inner mitochondrial membrane for subsequent ß-oxidation. Carnitine can be synthesized by the body and is also obtained in the diet through consumption of meat and dairy products. Defects in carnitine transport such as those caused by defective activity of the OCTN2 transporter encoded by the SLC22A5 gene result in primary carnitine deficiency, and newborn screening programmes can identify patients at risk for this condition before irreversible damage. Initial biochemical diagnosis can be confirmed through molecular testing, although direct study of carnitine transport in fibroblasts is very useful to confirm or exclude primary carnitine deficiency in individuals with genetic variations of unknown clinical significance or who continue to have low levels of carnitine despite negative molecular analyses. Genetic defects in carnitine biosynthesis do not generally result in low plasma levels of carnitine. However, deletion of the trimethyllysine hydroxylase gene, a key gene in carnitine biosynthesis, has been associated with non-dysmorphic autism. Thus, new roles for carnitine are emerging that are unrelated to classic inborn errors of metabolism.

Omics-Based Strategies in Precision Medicine: Toward a Paradigm Shift in Inborn Errors of Metabolism Investigations.

The rise of technologies that simultaneously measure thousands of data points represents the heart of systems biology. These technologies have had a huge impact on the discovery of next-generation diagnostics, biomarkers, and drugs in the precision medicine era. Systems biology aims to achieve systemic exploration of complex interactions in biological systems. Driven by high-throughput omics technologies and the computational surge, it enables multi-scale and insightful overviews of cells, organisms, and populations. Precision medicine capitalizes on these conceptual and technological advancements and stands on two main pillars: data generation and data modeling. High-throughput omics technologies allow the retrieval of comprehensive and holistic biological information, whereas computational capabilities enable high-dimensional data modeling and, therefore, accessible and user-friendly visualization. Furthermore, bioinformatics has enabled comprehensive multi-omics and clinical data integration for insightful interpretation. Despite their promise, the translation of these technologies into clinically actionable tools has been slow. In this review, we present state-of-the-art multi-omics data analysis strategies in a clinical context. The challenges of omics-based biomarker translation are discussed. Perspectives regarding the use of multi-omics approaches for inborn errors of metabolism (IEM) are presented by introducing a new paradigm shift in addressing IEM investigations in the post-genomic era.

Matrix-assisted laser desorption/ionization for simultaneous quantitation of (acyl-)carnitines and organic acids in dried blood spots.

RATIONALE: Screening for inborn errors of metabolism using mass spectrometry is part of nationwide newborn screening programs and involves the detection of disease relevant (acyl-)carnitines and organic acids from dried blood spots. Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a well-established tool for proteomics approaches. In recent years, this technique has become more and more integrated in analysis and identification of small metabolites and disease biomarkers in daily clinical laboratories. METHODS: We used a combination of both MALDI and high-resolution accurate mass (HR/AM) mass spectrometry using a linear ion trap-Orbitrap for the identification of small molecules from dried blood spots that serve as biomarkers for inborn errors of metabolism. The levels of detected metabolite species were compared between healthy newborns and affected patients with various inborn errors of metabolism using isotopically labeled internal standards and new bioinformatics software, respectively. RESULTS: (Acyl-)carnitine levels from normal and affected patients could be quantified and differentiated. Additionally, using the high resolving power of full scan Orbitrap mass spectrometry and novel software tools we demonstrated the identification and quantification of disease-specific organic acids. CONCLUSIONS: MALDI-HR/AM and full scan spectra to obtain information for the metabolic status of patients is a promising complementary approach to electrospray ionization mass spectrometry by simplified sample preparation, facilitating the screening of hundreds of metabolites from small sample volumes.

[Congenital chloride diarrhea mimicking meconium ileus in newborn]. / Wrodzona biegunka chlorowa u noworodka imitujaca niedroznosc smolkowa.

Congenital chloride diarrhoea is a rare autosomal recessive disease and the diagnosis is frequently delayed. The disease is most common in Saudi Arabia and Kuwait 1:3200-13 000 births, Finland - 1:30 000-40 000, and in Poland - 1:200 000. Congenital chloride diarrhoea begins in fetal life. The main clinical sign is watery diarrhea that in utero leads to dilated bowel loops, polyhydramnios and often premature birth. Newborns have distended abdomens, absence of meconium, dilated bowel loops in ultrasonography and watery diarrhea which can sometimes be mistaken for urine. The absence of meconium and the distended abdomen suggest meconium ileus or Hirschsprung disease and can lead to unnecessary surgical intervention. The article is a report on a 3-months old boy with the history of dilated bowel loops in prenatal ultrasonograhy, low birth weight and abdominal distention. Because of the suspicion of mechanical bowel obstruction he had laparotomy on the second day of his life. Mechanical obstruction was excluded and enterostomy was performed. Hyponatremia, hypokaliemia and metabolic alkalosis were found in laboratory tests. The electrolyte disturbances were corrected and enterostomy was closed after six weeks. The final diagnosis of congenital chloride diarrhea was established two months later, when the patient was admitted to hospital again with severe watery diarrhea, metabolic alkalosis, hypochloraemia and hypokalemia. The stool chloride concentration was >90 mmol/L. Water and electrolyte deficits had been corrected. The patient was discharged home with supplementation of sodium, potassium and chloride. His follow-up was uneventful. He remains under the care of the pediatric clinic.