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2. |
- Bengtson, Per, et al.
(author)
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Serum transferrin carrying the xeno-tetrasaccharide NeuAc-Gal-GlcNAc2 is a biomarker of ALG1-CDG.
- 2016
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 39:1, s. 107-114
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Journal article (peer-reviewed)abstract
- ALG1-CDG (formerly CDG-Ik) is a subtype of congenital disorders of glycosylation (CDG) where the genetic defect disrupts the synthesis of the lipid-linked oligosaccharide precursor required for N-glycosylation. The initial step in the investigation for these disorders involves the demonstration of hypoglycosylated serum transferrin (TF). There are no specific biomarkers of this CDG subtype known to date. An LC/MS approach was used to analyze sera from patients with ALG1-CDG, PMM2-CDG, suspected CDG, and individuals with alcohol abuse. We show mass spectrometric data combined with data from enzymatic digestions that suggest the presence of a tetrasaccharide consisting of two N-acetylglucosamines, one galactose, and one sialic acid, appearing on serum TF, is a biomarker of this particular CDG subtype. This is the first time analysis of serum TF can suggest a specific CDG type I subtype and we suggest this tetrasaccharide be used in the clinic to guide the ALG1-CDG diagnostic process.
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3. |
- Burda, P, et al.
(author)
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Characterization and review of MTHFD1 deficiency: four new patients, cellular delineation and response to folic and folinic acid treatment.
- 2015
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 38:5, s. 863-872
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Journal article (peer-reviewed)abstract
- In the folate cycle MTHFD1, encoded by MTHFD1, is a trifunctional enzyme containing 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase activity. To date, only one patient with MTHFD1 deficiency, presenting with hyperhomocysteinemia, megaloblastic anaemia, hemolytic uremic syndrome (HUS) and severe combined immunodeficiency, has been identified (Watkins et al J Med Genet 48:590-2, 2011). We now describe four additional patients from two different families. The second patient presented with hyperhomocysteinemia, megaloblastic anaemia, HUS, microangiopathy and retinopathy; all except the retinopathy resolved after treatment with hydroxocobalamin, betaine and folinic acid. The third patient developed megaloblastic anaemia, infection, autoimmune disease and moderate liver fibrosis but not hyperhomocysteinemia, and was successfully treated with a regime that included and was eventually reduced to folic acid. The other two, elder siblings of the third patient, died at 9weeks of age with megaloblastic anaemia, infection and severe acidosis and had MTFHD1 deficiency diagnosed retrospectively. We identified a missense mutation (c.806C>T, p.Thr296Ile) and a splice site mutation (c.1674G>A) leading to exon skipping in the second patient, while the other three harboured a missense mutation (c.146C>T, p.Ser49Phe) and a premature stop mutation (c.673G>T, p.Glu225*), all of which were novel. Patient fibroblast studies revealed severely reduced methionine formation from [(14)C]-formate, which did not increase in cobalamin supplemented culture medium but was responsive to folic and folinic acid. These additional cases increase the clinical spectrum of this intriguing defect, provide in vitro evidence of disturbed methionine synthesis and substantiate the effectiveness of folic or folinic acid treatment.
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4. |
- Burke, Derek G., et al.
(author)
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Increased glucocerebrosidase (GBA) 2 activity in GBA1 deficient mice brains and in Gaucher leucocytes
- 2013
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 36:5, s. 869-872
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Journal article (peer-reviewed)abstract
- Lysosomal glucocerebrosidase (GBA1) deficiency is causative for Gaucher disease. Not all individuals with GBA1 mutations develop neurological involvement raising the possibility that other factors may provide compensatory protection. One factor may be the activity of the non-lysosomal beta-glucosidase (GBA2) which exhibits catalytic activity towards glucosylceramide and is reported to be highly expressed in brain tissue. Here, we assessed brain GBA2 enzymatic activity in wild type, heterozygote and GBA1 deficient mice. Additionally, we determined activity in leucocytes obtained from 13 patients with Gaucher disease, 10 patients with enzymology consistent with heterozygote status and 19 controls. For wild type animals, GBA2 accounted for over 85 % of total brain GBA activity and was significantly elevated in GBA1 deficient mice when compared to heterozygote and wild types (GBA1 deficient; 92.4 +/- 5.6, heterozygote; 71.5 +/- 2.4, wild type 76.8 +/- 5.1 nmol/h/mg protein). For the patient samples, five Gaucher patients had GBA2 leucocyte activities markedly greater than controls. No difference in GBA2 activity was apparent between the control and carrier groups. Undetectable GBA2 activity was identified in four leucocyte preparations; one in the control group, two in the carrier group and one from the Gaucher disease group. Work is now required to ascertain whether GBA2 activity is a disease modifying factor in Gaucher disease and to identify the mechanism(s) responsible for triggering increased GBA2 activity in GBA1 deficiency states.
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6. |
- D'angelo, Barbara, et al.
(author)
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Expression of the Nrf2-system at the blood-CSF barrier is modulated by neonatal inflammation and hypoxia-ischemia
- 2013
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 36:3, s. 479-490
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Journal article (peer-reviewed)abstract
- ORIGINAL ARTICLE Expression of the Nrf2-system at the blood-CSF barrier is modulated by neonatal inflammation and hypoxia-ischemia Barbara D ’ Angelo & C. Joakim Ek & Mats Sandberg & Carina Mallard Received: 29 May 2012 /Revised: 14 September 2012 /Accepted: 10 October 2012 /Published online: 30 October 2012 # SSIEM and Springer Science+Business Media Dordrecht 2012 Abstract Transcription factor NF-E2-related factor-2 (Nrf2) is a key regulator of endogenous anti-oxidant sys- tems shown to play a neuroprotective role in the adult by preserving blood – brain barrier function. The choroid plex- us, site for the blood-CSF barrier, has been suggested to be particularly important in maintaining brain barrier function in development. We investigated the expression of Nrf2- and detoxification-system genes in choroid plexus following systemic LPS injections, unilateral cerebral hypoxia- ischemia (HI) as well as the combination of LPS and HI (LPS/HI). Plexuses were collected at different time points after LPS, HI and LPS/HI in 9-day old mice. mRNA levels of Nrf2 and many of its target genes were analyzed by quantitative PCR. Cell death was analyzed by caspase-3 immunostaining and TUNEL. LPS caused down-regulation of the Nrf2-system genes while HI increased expression at earlier time points. LPS exposure prior to HI prevented many of the HI-induced gene increases. None of the insults resulted in any apparent cell death to choroidal epithelium. These data imply that the function of the inducible anti- oxidant system in the choroid plexus is down-regulated by inflammation, even if choroid cells are not structurally damaged. Further, LPS prevented the endogenous antioxi- dant response following HI, suggesting the possibility that the choroid plexus may be at risk if LPS is united with an insult that increases oxidative stress such as hypoxia- ischemia.
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7. |
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8. |
- Haglind, C Bieneck, et al.
(author)
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Increased and early lipolysis in children with long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency during fast
- 2015
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 38:2, s. 315-322
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Journal article (peer-reviewed)abstract
- Children with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) have a defect in the degradation of long-chain fatty acids and are at risk of hypoketotic hypoglycemia and insufficient energy production as well as accumulation of toxic fatty acid intermediates. Knowledge on substrate metabolism in children with LCHAD deficiency during fasting is limited. Treatment guidelines differ between centers, both as far as length of fasting periods and need for night feeds are concerned. To increase the understanding of fasting intolerance and improve treatment recommendations, children with LCHAD deficiency were investigated with stable isotope technique, microdialysis, and indirect calometry, in order to assess lipolysis and glucose production during 6 h of fasting. We found an early and increased lipolysis and accumulation of long chain acylcarnitines after 4 h of fasting, albeit no patients developed hypoglycemia. The rate of glycerol production, reflecting lipolysis, averaged 7.7 ± 1.6 µmol/kg/min, which is higher compared to that of peers. The rate of glucose production was normal for age; 19.6 ± 3.4 µmol/kg/min (3.5 ± 0.6 mg/kg/min). Resting energy expenditure was also normal, even though the respiratory quotient was increased indicating mainly glucose oxidation. The results show that lipolysis and accumulation of long chain acylcarnitines occurs before hypoglycemia in fasting children with LCHAD, which may indicate more limited fasting tolerance than previously suggested.
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9. |
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10. |
- Halldin Stenlid, Maria U., et al.
(author)
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Increased lipolysis in LCHAD deficiency
- 2007
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 30:1, s. 39-46
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Journal article (peer-reviewed)abstract
- An increasing number of fatty acid oxidation defects are being detected owing to diagnostic improvements and a greater awareness among clinicians. The metabolic block leads to energy disruption, fatty infiltration, and toxic effects on organ functions exerted by β-oxidation metabolites. This investigation was undertaken to assess the influence of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency on lipolysis and energy turnover. We addressed the question whether the lipolysis and glucose production rates would be altered in the fasting state in a child with this disease. Lipolysis, glucose production and resting energy expenditure (REE) were studied in a 17-month-old girl with LCHAD deficiency and her healthy twin sister. Lipolysis and glucose production were determined after a 4–6 h fast by constant-rate infusion of [1,1,2,3,3-2H5]glycerol and [6,6-2H2]glucose and analysis by gas chromatography–mass spectrometry. REE was estimated by indirect calorimetry. The affected girl showed 50% higher lipolysis than did her sister, whereas the glucose production rates were similar. Plasma levels of dicarboxylic acids of 6–12 carbon atoms chain length, 3-hydroxy fatty acids of 6–18 carbon atoms chain length, total free fatty acids, and acylcarnitines were increased in the patient, as was REE. Since glucose production rates and plasma glucose levels were similar in the two girls, the increased lipolysis observed in the patient probably represents a compensatory mechanism for energy generation. This is achieved at the price of an augmented risk for fatty acid infiltration and toxic effects of β-oxidation intermediates. This highlights the importance of avoiding fasting in these patients.
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11. |
- Hikmat, O., et al.
(author)
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Simplifying the clinical classification of polymerase gamma (POLG) disease based on age of onset; studies using a cohort of 155 cases
- 2020
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 43:4, s. 726-736
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Journal article (peer-reviewed)abstract
- Background: Variants in POLG are one of the most common causes of inherited mitochondrial disease. Phenotypic classification of POLG disease has evolved haphazardly making it complicated and difficult to implement in everyday clinical practise. The aim of our study was to simplify the classification and facilitate better clinical recognition. Methods: A multinational, retrospective study using data from 155 patients with POLG variants recruited from seven European countries. Results: We describe the spectrum of clinical features associated with POLG variants in the largest known cohort of patients. While clinical features clearly form a continuum, stratifying patients simply according to age of onset—onset prior to age 12 years; onset between 12 and 40 years and onset after the age of 40 years, permitted us to identify clear phenotypic and prognostic differences. Prior to 12 years of age, liver involvement (87%), seizures (84%), and feeding difficulties (84%) were the major features. For those with onset between 12 and 40 years, ataxia (90%), peripheral neuropathy (84%), and seizures (71%) predominated, while for those with onset over 40 years, ptosis (95%), progressive external ophthalmoplegia (89%), and ataxia (58%) were the major clinical features. The earlier the onset the worse the prognosis. Patients with epilepsy and those with compound heterozygous variants carried significantly worse prognosis. Conclusion: Based on our data, we propose a simplified POLG disease classification, which can be used to guide diagnostic investigations and predict disease course. © 2020 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM
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12. |
- Jennions, Elizabeth, et al.
(author)
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TANGO2 deficiency as a cause of neurodevelopmental delay with indirect effects on mitochondrial energy metabolism
- 2019
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 42:5, s. 898-908
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Journal article (peer-reviewed)abstract
- Exome sequencing has recently identified mutations in the gene TANGO2 (transport and Golgi organization 2) as a cause of developmental delay associated with recurrent crises involving rhabdomyolysis, cardiac arrhythmias, and metabolic derangements. The disease is not well understood, in part as the cellular function and subcellular localization of the TANGO2 protein remain unknown. Furthermore, the clinical syndrome with its heterogeneity of symptoms, signs, and laboratory findings is still being defined. Here, we describe 11 new cases of TANGO2-related disease, confirming and further expanding the previously described clinical phenotype. Patients were homozygous or compound heterozygous for previously described exonic deletions or new frameshift, splice site, and missense mutations. All patients showed developmental delay with ataxia, dysarthria, intellectual disability, or signs of spastic diplegia. Of importance, we identify two subjects (aged 12 and 17 years) who have never experienced any overt episode of the catabolism-induced metabolic crises typical for the disease. Mitochondrial complex II activity was mildly reduced in patients investigated in association with crises but normal in other patients. In one deceased patient, post-mortem autopsy revealed heterotopic neurons in the cerebral white matter, indicating a possible role for TANGO2 in neuronal migration. Furthermore, we have addressed the subcellular localization of several alternative isoforms of TANGO2, none of which were mitochondrial but instead appeared to have a primarily cytoplasmic localization. Previously described aberrations in Golgi morphology were not observed in cultured skin fibroblasts.
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13. |
- Johnstone, Devon L., et al.
(author)
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Early infantile epileptic encephalopathy due to biallelic pathogenic variants in PIGQ : Report of seven new subjects and review of the literature
- 2020
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 43:6, s. 1321-1332
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Journal article (peer-reviewed)abstract
- 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 reviewed and flow cytometry and transfection experiments were performed to investigate PIGQ function. Pathogenic biallelic PIGQ variants were associated with increased mortality. Epileptic seizures, axial hypotonia, developmental delay and multiple congenital anomalies were consistently observed. Seizure onset occurred between 2.5 months and 7 months of age and varied from treatable seizures to recurrent episodes of status epilepticus. Gastrointestinal issues were common and severe, two affected individuals had midgut volvulus requiring surgical correction. Cardiac anomalies including arrythmias were observed. Flow cytometry using granulocytes and fibroblasts from affected individuals showed reduced expression of glycosylphosphatidylinositol (GPI)-anchored proteins. Transfection of wildtype PIGQ cDNA into patient fibroblasts rescued this phenotype. We expand the phenotypic spectrum of PIGQ-related disease and provide the first functional evidence in human cells of defective GPI-anchoring due to pathogenic variants in PIGQ.
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16. |
- Kilimann, M. W., et al.
(author)
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Glycogen pathways in disease: new developments in a classical field of medical genetics
- 2015
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 38:3, s. 483-487
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Journal article (peer-reviewed)abstract
- Glycogen is the storage form of glucose in animal cells. Its degradation can rapidly provide fuel for energy production (particularly important in muscle), or replenish blood glucose during fasting by the liver. Genetic defects of glycogen metabolism give rise to glycogen storage diseases (GSDs), manifesting histologically in abnormal quantity or quality of glycogen in the cells. GSDs can be caused by defects of proteins participating in the synthesis or degradation of glycogen itself, in the glycolytic degradation of glucose phosphates in muscle and erythrocytes, in the release of glucose from liver and kidney into the bloodstream, in the clearance of glycogen from lysosomes (all, "primary GSDs"), or in the control of these pathways ("secondary GSDs"). Most genes responsible for classical, primary GSDs have probably been identified, and future progress in understanding the biochemical and genetic defects underlying unsolved disorders presenting with glycogen storage abnormalities will perhaps be predominantly in the field of secondary GSDs.
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17. |
- Koens, Lisette H, et al.
(author)
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Eye movement disorders in inborn errors of metabolism : A quantitative analysis of 37 patients
- 2022
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 45:5, s. 981-995
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Journal article (peer-reviewed)abstract
- 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.
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19. |
- Kölker, Stefan, et al.
(author)
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Diagnosis and management of glutaric aciduria type I--revised recommendations.
- 2011
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In: Journal of inherited metabolic disease. - : Wiley. - 1573-2665 .- 0141-8955. ; 34:3, s. 677-94
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Journal article (peer-reviewed)abstract
- Glutaric aciduria type I (synonym, glutaric acidemia type I) is a rare organic aciduria. Untreated patients characteristically develop dystonia during infancy resulting in a high morbidity and mortality. The neuropathological correlate is striatal injury which results from encephalopathic crises precipitated by infectious diseases, immunizations and surgery during a finite period of brain development, or develops insidiously without clinically apparent crises. Glutaric aciduria type I is caused by inherited deficiency of glutaryl-CoA dehydrogenase which is involved in the catabolic pathways of L-lysine, L-hydroxylysine and L-tryptophan. This defect gives rise to elevated glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine which can be detected by gas chromatography/mass spectrometry (organic acids) or tandem mass spectrometry (acylcarnitines). Glutaric aciduria type I is included in the panel of diseases that are identified by expanded newborn screening in some countries. It has been shown that in the majority of neonatally diagnosed patients striatal injury can be prevented by combined metabolic treatment. Metabolic treatment that includes a low lysine diet, carnitine supplementation and intensified emergency treatment during acute episodes of intercurrent illness should be introduced and monitored by an experienced interdisciplinary team. However, initiation of treatment after the onset of symptoms is generally not effective in preventing permanent damage. Secondary dystonia is often difficult to treat, and the efficacy of available drugs cannot be predicted precisely in individual patients. The major aim of this revision is to re-evaluate the previous diagnostic and therapeutic recommendations for patients with this disease and incorporate new research findings into the guideline.
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20. |
- Lehtonen, J. M., et al.
(author)
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Diagnostic value of serum biomarkersFGF21andGDF15compared to muscle sample in mitochondrial disease
- 2021
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 44:2, s. 469-480
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Journal article (peer-reviewed)abstract
- The aim of this study was to compare the value of serum biomarkers, fibroblast growth factor 21 (FGF21) and growth differentiation factor 15 (GDF15), with histological analysis of muscle in the diagnosis of mitochondrial disease. We collected 194 serum samples from patients with a suspected or known mitochondrial disease. Biomarkers were analyzed blinded using enzyme-labeled immunosorbent assay. Clinical data were collected using a structured questionnaire. Only 39% of patients with genetically verified mitochondrial disease had mitochondrial pathology in their muscle histology. In contrast, biomarkers were elevated in 62% of patients with genetically verified mitochondrial disease. Those with both biomarkers elevated had a muscle manifesting disorder and a defect affecting mitochondrial DNA expression. If at least one of the biomarkers was induced and the patient had a myopathic disease, a mitochondrial DNA expression disease was the cause with 94% probability. Among patients with biomarker analysis and muscle biopsy taken <12 months apart, a mitochondrial disorder would have been identified in 70% with analysis of FGF21 and GDF15 compared to 50% of patients whom could have been identified with muscle biopsy alone. Muscle findings were nondiagnostic in 72% (children) and 45% (adults). Induction of FGF21 and GDF15 suggest a mitochondrial etiology as an underlying cause of a muscle manifesting disease. Normal biomarker values do not, however, rule out a mitochondrial disorder, especially if the disease does not manifest in muscle. We suggest that FGF21 and GDF15 together should be first-line diagnostic investigations in mitochondrial disease complementing muscle biopsy.
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23. |
- Machaczka, Maciej, et al.
(author)
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Gaucher disease with foamy transformed macrophages and erythrophagocytic activity
- 2011
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 34:1, s. 233-235
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Journal article (peer-reviewed)abstract
- Foamy transformation of macrophages is typically seen in lysosomal storage disorders in patients with Niemann-Pick disease, but foamy Gaucher cells (GC) were previously reported only once, in the autopsy report. Although the majority of stored glucocerebroside in GC is of erythrocyte origin, apparent erythrophagocytosis by GC in bone marrow is an unusual finding. Here, we describe the case of an adult non-Jewish Caucasian male with a heterozygous Gaucher disease type 1 (mutations c.1226A>G and c.1448T>C in the GBA1 gene) who presented with atypical morphology of GC on bone marrow examination. Approximately 15% of his GC showed a notable erythrophagocytic activity or unusual appearance of foamy transformed macrophages with a great number of vacuoles and erythrocyte rests in the cytoplasm. This report highlights the fact that morphological examination of cells and tissue specimens is very helpful in the diagnosis of a storage disorder but that confirmatory testing for specific diseases should always follow. Moreover, it is now clear that Gaucher disease should be a part of the differential diagnosis of foamy transformed macrophages.
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25. |
- Nakajima, Yoko, et al.
(author)
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Clinical, biochemical and molecular analysis of 13 Japanese patients with beta-ureidopropionase deficiency demonstrates high prevalence of the c.977G > A (p.R326Q) mutation
- 2014
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 37:5, s. 801-812
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Journal article (peer-reviewed)abstract
- beta-ureidopropionase (beta UP) deficiency is an autosomal recessive disease characterized by N-carbamyl-beta-amino aciduria. To date, only 16 genetically confirmed patients with beta UP deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 13 Japanese beta UP deficient patients. In this group of patients, three novel missense mutations (p.G31S, p.E271K, and p.I286T) and a recently described mutation (p.R326Q) were identified. The p.R326Q mutation was detected in all 13 patients with eight patients being homozygous for this mutation. Screening for the p.R326Q mutation in 110 Japanese individuals showed an allele frequency of 0.9 %. Transient expression of mutant beta UP enzymes in HEK293 cells showed that the p.E271K and p.R326Q mutations cause profound decreases in activity (a parts per thousand currency sign 1.3 %). Conversely, beta UP enzymes containing the p.G31S and p.I286T mutations possess residual activities of 50 and 70 %, respectively, suggesting we cannot exclude the presence of additional mutations in the non-coding region of the UPB1 gene. Analysis of a human beta UP homology model revealed that the effects of the mutations (p.G31S, p.E271K, and p.R326Q) on enzyme activity are most likely linked to improper oligomer assembly. Highly variable phenotypes ranging from neurological involvement (including convulsions and autism) to asymptomatic, were observed in diagnosed patients. High prevalence of p.R326Q in the normal Japanese population indicates that beta UP deficiency is not as rare as generally considered and screening for beta UP deficiency should be included in diagnosis of patients with unexplained neurological abnormalities.
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26. |
- Ng, Bobby G, et al.
(author)
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Predominant and novel de novo variants in 29 individuals with ALG13 deficiency: Clinical description, biomarker status, biochemical analysis, and treatment suggestions
- 2020
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 43:6, s. 1333-1348
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Journal article (peer-reviewed)abstract
- 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 glycosylation, it is also considered a congenital disorder of glycosylation (CDG), ALG13-CDG. Twenty-four previously reported ALG13-CDG cases had de novo variants, but surprisingly, unlike most forms of CDG, ALG13-CDG did not show the anticipated glycosylation defects, typically detected by altered transferrin glycosylation. Structural homology modeling of two recurrent de novo variants, p.A81T and p.N107S, suggests both are likely to impact the function of ALG13. Using a corresponding ALG13-deficient yeast strain, we show that expressing yeast ALG13 with either of the highly conserved hotspot variants rescues the observed growth defect, but not its glycosylation abnormality. We present molecular and clinical data on 29 previously unreported individuals with de novo variants in ALG13. This more than doubles the number of known cases. A key finding is that a vast majority of the individuals presents with West syndrome, a feature shared with other CDG types. Among these, the initial epileptic spasms best responded to adrenocorticotropic hormone or prednisolone, while clobazam and felbamate showed promise for continued epilepsy treatment. A ketogenic diet seems to play an important role in the treatment of these individuals. © 2020 SSIEM
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28. |
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30. |
- Oldfors Hedberg, Carola, 1969, et al.
(author)
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Cardiomyopathy as presenting sign of glycogenin-1 deficiency-report of three cases and review of the literature.
- 2017
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In: Journal of inherited metabolic disease. - : Wiley. - 1573-2665 .- 0141-8955. ; 40:1, s. 139-149
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Journal article (peer-reviewed)abstract
- We describe a new type of cardiomyopathy caused by a mutation in the glycogenin-1 gene (GYG1). Three unrelated male patients aged 34 to 52years with cardiomyopathy and abnormal glycogen storage on endomyocardial biopsy were homozygous for the missense mutation p.Asp102His in GYG1. The mutated glycogenin-1 protein was expressed in cardiac tissue but had lost its ability to autoglucosylate as demonstrated by an in vitro assay and western blot analysis. It was therefore unable to form the primer for normal glycogen synthesis. Two of the patients showed similar patterns of heart dilatation, reduced ejection fraction and extensive late gadolinium enhancement on cardiac magnetic resonance imaging. These two patients were severely affected, necessitating cardiac transplantation. The cardiomyocyte storage material was characterized by large inclusions of periodic acid and Schiff positive material that was partly resistant to alpha-amylase treatment consistent with polyglucosan. The storage material had, unlike normal glycogen, a partly fibrillar structure by electron microscopy. None of the patients showed signs or symptoms of muscle weakness but a skeletal muscle biopsy in one case revealed muscle fibres with abnormal glycogen storage. Glycogenin-1 deficiency is known as a rare cause of skeletal muscle glycogen storage disease, usually without cardiomyopathy. We demonstrate that it may also be the cause of severe cardiomyopathy and cardiac failure without skeletal muscle weakness. GYG1 should be included in cardiomyopathy gene panels.
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31. |
- Oliveira, JP, et al.
(author)
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Effect of single-nucleotide polymorphisms of the 5' untranslated region of the human alpha-galactosidase gene on enzyme activity, and their frequencies in Portuguese caucasians.
- 2008
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In: Journal of inherited metabolic disease. - : Wiley. - 1573-2665 .- 0141-8955. ; 31:2, s. 247-253
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Journal article (peer-reviewed)abstract
- BACKGROUND: The alpha-galactosidase gene (GLA) has three single-nucleotide polymorphisms in the 5' untranslated region of exon 1, respectively g.1150G>A, g.1168G>A, g.1170C>T. The g.1150A allele is associated with increased plasma alpha-galactosidase (alpha-Gal) activity in hemizygotes, while the others are regarded as biologically neutral. The primary goal of this investigation was to test the hypothesis, raised by a clinical observation and results of a family study, that the g.1170T allele polymorphism is associated with lower alpha-Gal expression. SUBJECTS AND METHODS: Plasma and leukocyte alpha-Gal activities were assayed in unrelated healthy young adults of both sexes, who had been genotyped for GLA exon 1, and enzyme activity values in carriers of any of the polymorphisms were compared to those of individuals with the standard genotype; GLA exon 1 was genotyped in males who had alpha-Gal activity in dried blood spots lower than 2 SD below the cohort average. RESULTS AND CONCLUSIONS: Mean alpha-Gal leukocyte activity was approximately 25% higher in subjects with the g.1170C or CC genotype than in those with the alternative genotypes (p < 0.05). The frequency of the g.1170T allele in subjects with low alpha-Gal activity in dried blood spots was 4-fold higher (p < 0.05) than in the general population. As in hemizygotes, the g.1150A heterozygote identified in this study had plasma alpha-Gal activity more than 2-fold above the normal mean. The g.1168A allele did not affect enzyme activity. Surprisingly, females with the standard GLA exon 1 genotype had significantly higher plasma alpha-Gal activity than genetically comparable males.
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32. |
- Oliveira, JP, et al.
(author)
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The g.1170C>T polymorphism of the 5' untranslated region of the human alpha-galactosidase gene is associated with decreased enzyme expression-Evidence from a family study.
- 2008
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In: Journal of inherited metabolic disease. - : Wiley. - 1573-2665 .- 0141-8955. ; 31:Suppl. 2, s. 405-413
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Journal article (peer-reviewed)abstract
- Subnormal leukocyte alpha-galactosidase (alpha-Gal) activity was found during evaluation of an adolescent male with cryptogenic cerebrovascular small-vessel disease. The only molecular abnormality found was the g.1170C>T single-nucleotide polymorphism (SNP) in the 5' untranslated region of exon 1 in the alpha-Gal gene (GLA). Historically, this polymorphism has been considered to be biologically neutral. To test the hypothesis that the g.1170T allele might be associated with lower alpha-Gal expression, we genotyped GLA exon 1 and measured leukocyte and plasma alpha-Gal in the parents, brother and sister of the index case. The g.1170T allele co-segregated with a subnormal leukocyte alpha-Gal activity in the three siblings. Although plasma enzyme activities were within the normal range in all five relatives, the ranking of their values suggested a dosage effect of the g.1170T allele. Western blotting assays of leukocyte protein extracts showed that the relative expression of alpha-Gal in both the patient and his sister was significantly lower than in sex-matched hemizygous or homozygous controls for the g.1170C allele, either normalized to the beta-actin immunoblot expression or standardized to a known amount of recombinant human alpha-Gal. These family data, in combination with results from a recent GLA SNP screening study among healthy Portuguese individuals, suggest that the g.1170C>T SNP may be co-dominantly associated with a relatively decreased GLA expression at the transcription and/or translation level. Larger population studies are needed to confirm these findings and to test the hypothesis that the GLA g.1170C>T may contribute to the multifactorial risk of ischaemic small-vessel cerebrovascular disease.
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33. |
- Olsson, G. M., et al.
(author)
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Family conditions and dietary control in phenylketonuria
- 2007
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In: Journal of Inherited Metabolic Disease. - Berlin : Springer. - 0141-8955 .- 1573-2665. ; 30:5, s. 708-715
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Journal article (peer-reviewed)abstract
- Objective This investigation is an attempt to describe coping with phenylketonuria (PKU) in order to understand some aspects underlying good compliance. Methods The coping concept was applied to PKU in two questionnaires. Self- and parental ratings were combined with assessments of phenylalanine levels and the severity of the disease. All Swedish patients with PKU born in 1980–91, a total of 53 children and youths with their parents, were invited to participate in the study and 41 (77%) of them did so. Results The patients turned out to have good compliance with the diet. The main result was that patients with separated or divorced parents were more likely to have higher phenylalanine levels and this association was not diminished by adjustment for the potential confounding factors. Conclusion Patients’ need for support must be judged individually according to different family conditions.
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34. |
- Park, Julien H., et al.
(author)
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N-glycome analysis detects dysglycosylation missed by conventional methods in SLC39A8 deficiency
- 2020
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In: Journal of Inherited Metabolic Disease. - : John Wiley & Sons. - 0141-8955 .- 1573-2665. ; 43:6, s. 1370-1381
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Journal article (peer-reviewed)abstract
- Congenital disorders of glycosylation (CDG) are a growing group of inborn metabolic disorders with multiorgan presentation. SLC39A8‐CDG is a severe subtype caused by biallelic mutations in the manganese transporter SLC39A8, reducing levels of this essential cofactor for many enzymes including glycosyltransferases. The current diagnostic standard for disorders of N‐glycosylation is the analysis of serum transferrin. Exome and Sanger sequencing were performed in two patients with severe neurodevelopmental phenotypes suggestive of CDG. Transferrin glycosylation was analyzed by high‐performance liquid chromatography (HPLC) and isoelectric focusing in addition to comprehensive N‐glycome analysis using matrix‐assisted laser desorption ionization time of flight (MALDI‐TOF) mass spectrometry (MS). Atomic absorption spectroscopy was used to quantify whole blood manganese levels. Both patients presented with a severe, multisystem disorder, and a complex neurological phenotype. Magnetic resonance imaging (MRI) revealed a Leigh‐like syndrome with bilateral T2 hyperintensities of the basal ganglia. In patient 1, exome sequencing identified the previously undescribed homozygous variant c.608T>C [p.F203S] in SLC39A8. Patient 2 was found to be homozygous for c.112G>C [p.G38R]. Both individuals showed a reduction of whole blood manganese, though transferrin glycosylation was normal. N‐glycome using MALDI‐TOF MS identified an increase of the asialo‐agalactosylated precursor N‐glycan A2G1S1 and a decrease in bisected structures. In addition, analysis of heterozygous CDG‐allele carriers identified similar but less severe glycosylation changes. Despite its reliance as a clinical gold standard, analysis of transferrin glycosylation cannot be categorically used to rule out SLC39A8‐CDG. These results emphasize that SLC39A8‐CDG presents as a spectrum of dysregulated glycosylation, and MS is an important tool for identifying deficiencies not detected by conventional methods.
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35. |
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36. |
- Phadke, R., et al.
(author)
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RBCK1-related disease: A rare multisystem disorder with polyglucosan storage, auto-inflammation, recurrent infections, skeletal, and cardiac myopathy—Four additional patients and a review of the current literature
- 2020
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 43:5, s. 1002-1013
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Journal article (peer-reviewed)abstract
- 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 muscle MRI findings. © 2020 SSIEM
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37. |
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38. |
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39. |
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40. |
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41. |
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42. |
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43. |
- Savvidou, Antri, et al.
(author)
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Novel imaging findings in pyruvate dehydrogenase complex (PDHc) deficiency—Results from a nationwide population-based study
- 2022
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 45:2, s. 248-263
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Journal article (peer-reviewed)abstract
- The vast clinical and radiological spectrum of pyruvate dehydrogenase complex (PDHc) deficiency continues to pose challenges both in diagnostics and disease monitoring. Prompt diagnosis is important to enable early initiation of ketogenic diet. The patients were recruited from an ongoing population-based study in Sweden. All patients with a genetically confirmed diagnosis who had been investigated with an MRI of the brain were included. Repeated investigations were assessed to study the evolution of the MRI changes. Sixty-two MRI investigations had been performed in 34 patients (23 females). The genetic cause was mutations in PDHA1 in 29, PDHX and DLAT in 2 each, and PDHB in 1. The lesions were prenatal developmental in 16, prenatal clastic in 18, and postnatal clastic in 15 individuals. Leigh-like lesions with predominant involvement of globus pallidus were present in 12, while leukoencephalopathy was present in 6 and stroke-like lesions in 3 individuals. A combination of prenatal developmental and clastic lesions was present in 15 individuals. In addition, one male with PDHA1 also had postnatal clastic lesions. The most common lesions found in our study were agenesis or hypoplasia of corpus callosum, ventriculomegaly, or Leigh-like lesions. Furthermore, we describe a broad spectrum of other MRI changes that include leukoencephalopathy and stroke-like lesions. We argue that a novel important clue, suggesting the possibility of PDHc deficiency on MRI scans, is the simultaneous presence of multiple lesions on MRI that have occurred during different phases of brain development.
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44. |
- Schwantje, M., et al.
(author)
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Thermo-sensitive mitochondrial trifunctional protein deficiency presenting with episodic myopathy
- 2022
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 45:4, s. 819-831
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Journal article (peer-reviewed)abstract
- Mitochondrial trifunctional protein (MTP) is involved in long-chain fatty acid beta-oxidation (lcFAO). Deficiency of one or more of the enzyme activities as catalyzed by MTP causes generalized MTP deficiency (MTPD), long-chain hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), or long-chain ketoacyl-CoA thiolase deficiency (LCKATD). When genetic variants result in thermo-sensitive enzymes, increased body temperature (e.g. fever) can reduce enzyme activity and be a risk factor for clinical decompensation. This is the first description of five patients with a thermo-sensitive MTP deficiency. Clinical and genetic information was obtained from clinical files. Measurement of LCHAD and LCKAT activities, lcFAO-flux studies and palmitate loading tests were performed in skin fibroblasts cultured at 37 degrees C and 40 degrees C. In all patients (four MTPD, one LCKATD), disease manifested during childhood (manifestation age: 2-10 years) with myopathic symptoms triggered by fever or exercise. In four patients, signs of retinopathy or neuropathy were present. Plasma long-chain acylcarnitines were normal or slightly increased. HADHB variants were identified (at age: 6-18 years) by whole exome sequencing or gene panel analyses. At 37 degrees C, LCHAD and LCKAT activities were mildly impaired and lcFAO-fluxes were normal. Remarkably, enzyme activities and lcFAO-fluxes were markedly diminished at 40 degrees C. Preventive (dietary) measures improved symptoms for most. In conclusion, all patients with thermo-sensitive MTP deficiency had a long diagnostic trajectory and both genetic and enzymatic testing were required for diagnosis. The frequent absence of characteristic acylcarnitine abnormalities poses a risk for a diagnostic delay. Given the positive treatment effects, upfront genetic screening may be beneficial to enhance early recognition.
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45. |
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46. |
- Smet, Joel, et al.
(author)
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Complex III staining in blue native polyacrylamide gels
- 2011
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 34:3, s. 741-747
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Journal article (peer-reviewed)abstract
- For more than a decade now blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used for the study of the oxidative phosphorylation (OXPHOS) complexes. Catalytic activities of complexes I, II, IV and V can be assessed, after separation by gel electroforesis, by incubation of the BN-PAGE gel in specific staining solutions. However, until now, a reliable staining method for testing ubiquinol cytochrome c oxidoreductase (complex III) activity by BN-PAGE gel techniques was not available. In addition, spectrophotometric methods currently in use for detection of complex III deficiency in patients are not very sensitive. Here, we describe a newly developed diagnostic method for visualization of complex III activity by direct in-gel evaluation of ubiquinol cytochrome oxidoreductase activity. We validated the method by reporting the results in six patients with previously characterised complex III defects.
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47. |
- Sofou, Kalliopi, et al.
(author)
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Ketogenic diet in pyruvate dehydrogenase complex deficiency: short- and long-term outcomes.
- 2017
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In: Journal of inherited metabolic disease. - : Wiley. - 1573-2665 .- 0141-8955. ; 40:2, s. 237-245
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Journal article (peer-reviewed)abstract
- Our aime was to study the short- and long-term effects of ketogenic diet on the disease course and disease-related outcomes in patients with pyruvate dehydrogenase complex deficiency, the metabolic factors implicated in treatment outcomes, and potential safety and compliance issues.Pediatric patients diagnosed with pyruvate dehydrogenase complex deficiency in Sweden and treated with ketogenic diet were evaluated. Study assessments at specific time points included developmental and neurocognitive testing, patient log books, and investigator and parental questionnaires. A systematic literature review was also performed.Nineteen patients were assessed, the majority having prenatal disease onset. Patients were treated with ketogenic diet for a median of 2.9years. All patients alive at the time of data registration at a median age of 6years. The treatment had a positive effect mainly in the areas of epilepsy, ataxia, sleep disturbance, speech/language development, social functioning, and frequency of hospitalizations. It was also safe-except in one patient who discontinued because of acute pancreatitis. The median plasma concentration of ketone bodies (3-hydroxybutyric acid) was 3.3mmol/l. Poor dietary compliance was associated with relapsing ataxia and stagnation of motor and neurocognitive development. Results of neurocognitive testing are reported for 12 of 19 patients.Ketogenic diet was an effective and safe treatment for the majority of patients. Treatment effect was mainly determined by disease phenotype and attainment and maintenance of ketosis.
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48. |
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50. |
- Van Haute, L., et al.
(author)
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Mitochondrial transcript maturation and its disorders
- 2015
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In: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 38:4, s. 655-680
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Journal article (peer-reviewed)abstract
- Mitochondrial respiratory chain deficiencies exhibit a wide spectrum of clinical presentations owing to defective mitochondrial energy production through oxidative phosphorylation. These defects can be caused by either mutations in the mitochondrial DNA (mtDNA) or mutations in nuclear genes coding for mitochondrially-targeted proteins. The underlying pathomechanisms can affect numerous pathways involved in mitochondrial biology including expression of mtDNA-encoded genes. Expression of the mitochondrial genes is extensively regulated at the post-transcriptional stage and entails nucleolytic cleavage of precursor RNAs, RNA nucleotide modifications, RNA polyadenylation, RNA quality and stability control. These processes ensure proper mitochondrial RNA (mtRNA) function, and are regulated by dedicated, nuclear-encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of RNAs, are a cause of human mitochondrial disease. Additionally, mutations in mtDNA-encoded genes may also affect RNA maturation and are frequently associated with human disease. We review the current knowledge on a subset of nuclear-encoded genes coding for proteins involved in mitochondrial RNA maturation, for which genetic variants impacting upon mitochondrial pathophysiology have been reported. Also, primary pathological mtDNA mutations with recognised effects upon RNA processing are described.
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