| 51. |
- Schwantje, M., et al.
(författare)
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Thermo-sensitive mitochondrial trifunctional protein deficiency presenting with episodic myopathy
- 2022
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Ingår i: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 45:4, s. 819-831
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Tidskriftsartikel (refereegranskat)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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| 52. |
- Sofou, Kalliopi, et al.
(författare)
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Prenatal onset of mitochondrial disease is associated with sideroflexin 4 deficiency
- 2019
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Ingår i: Mitochondrion. - : Elsevier BV. - 1567-7249. ; 47, s. 76-81
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Tidskriftsartikel (refereegranskat)abstract
- Prenatal onset of mitochondrial disease has been described in two cases with recessive mutations in the sideroflexin 4 gene (SFXN4). We present a third case with complex I deficiency associated with novel mutations in SFXN4. Our patient presented with intrauterine growth retardation, neonatal lactic acidosis, and developed macrocytic anemia and optic nerve hypoplasia. Muscle mitochondrial investigations revealed ultrastructural abnormalities, severe deficiency of complex I enzyme activity, and loss of subunit proteins. Whole-exome sequencing revealed bi-allelic SFXN4 mutations: a 1-base deletion, c.969delG, leading to frameshift and a premature stop codon, p.(G1n323Hisfs*20), and a stop-loss mutation in the C-terminal region, c.1012 T > C; p. (*388Glnext2), resulting in elongation of the protein by two amino acids. Expression analysis of mRNA from muscle showed loss of SFXN4 transcripts.
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| 53. |
- Sofou, Kalliopi, et al.
(författare)
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The phenotypic variability and natural history of NARS2 associated disease
- 2021
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 31, s. 31-37
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The phenotypic variability of NARS2 associated disease is vast, yet not thoroughly explored. We present the phenotypic and genetic features of 2 siblings with early-onset mitochondrial encephalopathy due to pathogenic variant in NARS2, along with the results from a systematic literature review. Aims: To better delineate the phenotypic variability and natural history of NARS2 associated disease. Methods: The clinical and radiological phenotype, along with the results from the morphological and biochemical investigations from the muscle biopsy as well as the postmortem investigations, where applicable, are presented. Genetic analysis was performed with next-generation sequencing . Results: Together with these 2 patients, we have diagnosed and followed 3 Scandinavian patients with the same homozygous p. Pro214Leu variant in NARS2 who presented with phenotypic features of early onset mitochondrial encephalopathy and variable disease course. Another 14 patients with pathogenic variants in NARS2 were identified in the literature. We found that sensorineural hearing impairment is a cardinal feature of early-onset NARS2 associated disease, either isolated or in combination with central nervous system disease. Early-onset mitochondrial encephalopathy due to NARS2 variants shared phenotypic features of Alpers or Leigh syndrome and was characterized by more severe disease course and poorer survival compared to the other NARS2 associated phenotypes. Conclusion: NARS2 variants present with a spectrum of clinical severity from a severe, infantile-onset, progressive disease to a mild, non-progressive disease, without strong association between the genotype and the disease outcome. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of European Paediatric Neurology Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4. 0/).
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| 54. |
- Sundal, Christina, et al.
(författare)
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An AARS variant as the likely cause of Swedish type hereditary diffuse leukoencephalopathy with spheroids
- 2019
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Swedish type Hereditary Diffuse Leukoencephalopathy with Spheroids (HDLS-S) is a severe adult-onset leukoencephalopathy with the histopathological hallmark of neuraxonal degeneration with spheroids, described in a large family with a dominant inheritance pattern. The initial stage of the disease is dominated by frontal lobe symptoms that develop into a rapidly advancing encephalopathy with pyramidal, deep sensory, extrapyramidal and optic tract symptoms. Median survival is less than 10 years. Recently, pathogenic mutations in CSF1R were reported in a clinically and histologically similar leukoencephalopathy segregating in several families. Still, the cause of HDLS-S remained elusive since its initial description in 1984, with no CSF1R mutations identified in the family. Here we update the original findings associated with HDLS-S after asystematic and recent assessment of several family members. We also report the results from exome sequencing analysesindicating the p.Cys152Phe variant in the alanyl tRNA synthetase (AARS) gene as the probable cause of this disease. The variant affects an amino acid located in the aminoacylation domain of the protein and does not cause differences in splicing or expression in the brain. Brain pathology in one case after 10 years of disease duration showed the end stage of the disease to be characterized by widespread liquefaction of the white matter leaving only some macrophages and glial cells behind the centrifugally progressing front. These results point to AARS as a candidate gene for rapidly progressing adult onset CSF1R-negative leukoencephalopathies.
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| 55. |
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| 56. |
- Topa, Alexandra, et al.
(författare)
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Novel myopathy in a newborn with Shwachman-Diamond syndrome and review of neonatal presentation.
- 2016
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Ingår i: American journal of medical genetics. Part A. - : Wiley. - 1552-4833 .- 1552-4825. ; 170:5, s. 1155-1164
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Tidskriftsartikel (refereegranskat)abstract
- Shwachman-Diamond-Bodian syndrome (SDS) is a pleiotropic disorder in which the main features are bone marrow dysfunction and pancreatic insufficiency. Skeletal changes can occur, and in rare cases manifest as severe congenital thoracic dystrophy. We report a newborn boy with asphyxia, narrow thorax, and severe hypotonia initially suggesting a neuromuscular disease. The muscle biopsy showed myopathic changes with prominent variability in muscle fiber size and abnormal expression of developmental isoforms of myosin. The myofibrils showed focal loss and disorganization of myofilaments, and thickening of the Z-discs including some abortive nemaline rods. The boy became permanently dependent on assisted ventilation. Pancreatic insufficiency was subsequently diagnosed, explaining the malabsorption and failure to thrive. Except transitory thrombocytopenia and leukopenia, no major hematological abnormalities were noted. He had bilateral nephrocalcinosis with preserved renal function. Transitory liver dysfunction with elevated transaminase levels and parenchymal changes on ultrasound were registered. The clinical diagnosis was confirmed by detection of compound heterozygous mutations in SBDS using whole-exome sequencing: a recurrent intronic mutation causing aberrant splicing (c.258+2T>C) and a novel missense variant in a highly conserved codon (c.41A>G, p.Asn14Ser), considered to be damaging for the protein structure by in silico prediction programs. The carrier status of the parents has been confirmed. This case illustrates the challenges in differential diagnosis of pronounced neonatal hypotonia with asphyxia and highlights the muscular involvement in SDS. To our knowledge, this is the first report of myopathy evidenced in a patient with clinically and molecularly confirmed SDS. © 2016 Wiley Periodicals, Inc.
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| 57. |
- Visuttijai, Kittichate, et al.
(författare)
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Glycogenin is dispensable for glycogen synthesis in human muscle and glycogenin deficiency causes polyglucosan storage.
- 2020
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 105:2, s. 557-566
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the importance of glycogenin-1 and glycogenin-2 for glycogen synthesis in skeletal and cardiac muscle.Glycogenin-1 and glycogenin-2 expression was analyzed by western blot, mass spectrometry, and immunohistochemistry in liver, heart, and skeletal muscle from controls and in skeletal and cardiac muscle from patients with glycogenin-1 deficiency.Both glycogenin-1 and glycogenin-2 were found to be expressed in liver, but only glycogenin-1 was identified in heart and skeletal muscle from controls. In patients with truncating GYG1 mutations, neither glycogenin-1 nor glycogenin-2 was expressed in skeletal muscle. However, non-functional glycogenin-1 but not glycogenin-2 was identified in cardiac muscle from patients with cardiomyopathy due to GYG1 missense mutations. By immunohistochemistry, the mutated glycogenin-1 co-localized with the storage of glycogen and polyglucosan in cardiomyocytes.Glycogen can be synthesised in the absence of glycogenin, and glycogenin-1 deficiency is not compensated for by upregulation of functional glycogenin-2. Absence of glycogenin-1 leads to focal accumulation of glycogen and polyglucosan in skeletal muscle fibers. Expression of mutated glycogenin-1 in the heart is deleterious, and it leads to storage of abnormal glycogen and cardiomyopathy.
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| 58. |
- Visuttijai, Kittichate, et al.
(författare)
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Progressive external ophthalmoplegia associated with novelMT-TNmutations
- 2021
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 143:1, s. 103-108
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To describe two patients with progressive external ophthalmoplegia (PEO) and mitochondrial myopathy associated with mutations in mitochondrial DNA, encoding the tRNA(Asn)gene (MT-TN), which have not previously been published with clinical descriptions. Materials & Methods Two unrelated patients with PEO were clinically examined. Muscle biopsy was performed and investigated by exome sequencing, enzyme histochemistry, and immunohistochemistry. The level of heteroplasmy was investigated in single muscle fibers and in other tissues. Results Patient 1 was a 52-year-old man with ptosis, PEO, and exercise intolerance since childhood. Muscle biopsy demonstrated mitochondrial myopathy with frequent cytochromecoxidase (COX)-deficient fibers and a heteroplasmic mutation, m.5669G>A in theMT-TNgene, resulting in a substitution of a highly conserved C to T in the T stem of tRNA(Asn). Patient 2 was a 66-year-old woman with ptosis, PEO, and exercise intolerance since many years. Muscle biopsy demonstrated mitochondrial myopathy with frequent COX-deficient fibers. She had a novel m.5702delA mutation inMT-TN, resulting in loss of a highly conserved U in the anticodon stem of tRNA(Asn). Single fiber analysis in both cases showed highly significant differences in mutation load between COX-deficient and COX-normal fibers and a high threshold level for COX deficiency. The mutations were not found in blood, urine sediment or buccal cells. Conclusion We describe twoMT-TNmutations associated with PEO and mitochondrial myopathy, and their pathogenicity was demonstrated. Together with previous reports, the results indicate thatMT-TNis a hot spot for mutations causing sporadic PEO.
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| 59. |
- Willis, T., et al.
(författare)
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A novel MYH2 mutation in family members presenting with congenital myopathy, ophthalmoplegia and facial weakness
- 2016
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Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 263:7, s. 1427-1433
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Tidskriftsartikel (refereegranskat)abstract
- Myosin heavy chain (MyHC) is a major structural component of the striated muscle contractile apparatus. In adult human limb skeletal muscle, there are three major MyHC isoforms, slow/beta cardiac MyHC, MyHC IIa and MHC IIx, which are important for the functional characteristics of different muscle fiber types. Hereditary myosin myopathies have emerged as an important group of diseases with variable clinical and morphological expression dependent on the mutated isoform, and also the type and location of the mutation. Myosin myopathy with external ophthalmoplegia is associated with mutations in MYH2, encoding for MyHC IIa that is mainly expressed in type 2A muscle fibers and is inherited in dominant as well as recessive manner. We present a family with myopathy with early onset proximal muscle weakness, facial muscle involvement and ophthalmoplegia. Muscle biopsy demonstrated lack of type 2A muscle fibers and genetic work up demonstrated that the disease was caused by a novel recessive MYH2 mutation: c.1009-1G > A resulting in skipping of exon 12, which is predicted to result in a frame shift and introducing at premature stop codon at position 347 (p.Ser337Leufs*11).
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| 60. |
- Xia, Zhi Jie, et al.
(författare)
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The Swedish COG6-CDG experience and a comprehensive literature review
- 2023
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Ingår i: JIMD Reports. - : Wiley. - 2192-8304 .- 2192-8312. ; , s. 79-89
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Here, we present the first two Swedish cases of Conserved Oligomeric Golgi complex subunit 6-congenital disorders of glycosylation (COG6-CDG). Their clinical symptoms include intellectual disability, Attention Deficit/Hyperactivity Disorder (ADHD), delayed brain myelinization, progressive microcephaly, joint laxity, hyperkeratosis, frequent infections, and enamel hypoplasia. In one family, compound heterozygous variants in COG6 were identified, where one (c.785A>G; p.Tyr262Cys) has previously been described in patients of Moroccan descent, whereas the other (c.238G>A; p.Glu80Lys) is undescribed. On the other hand, a previously undescribed homozygous duplication (c.1793_1795dup) was deemed the cause of the disease. To confirm the pathogenicity of the variants, we treated patient and control fibroblasts with the ER-Golgi transport inhibitor Brefeldin-A and show that patient cells manifest a significantly slower anterograde and retrograde ER-Golgi transport.
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