| 1. |
- Björkman, Kristoffer, et al.
(författare)
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Clinical course of patients with single large-scale mtDNA deletions and childhood onset anemia
- 2022
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Ingår i: 14th European Paediatric Neurology Society Congress, Glasgow, UK (ISBN 978-3-00-072065-9).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To add to our knowledge of the clinical spectrum of patients with single large-scale mitochondrial DNA (mtDNA) deletion and childhood onset anemia. Methods: Retrospective collection of clinical data from medical records for patients, both living and deceased, with a single large-scale mtDNA deletion from seven mitochondrial disease centers in five countries. Statistical analysis with descriptive methods and Kaplan-Meier survival analysis. Results: Seventeen patients matching the genetic criterium and with anemia onset before six years of age. Exocrine pancreatic insufficiency was only seen in five patients in this group. Multiple organs were involved in all patients, with the most common non-hematologic ones being skeletal muscle, central nervous system, endocrine, eyes, gastrointestinal system, kidneys, hearing, liver and heart. Psychomotor retardation was seen in ten patients, hearing impairment in nine patients, failure to thrive in eight patients. Eight later developed Kearns-Sayre syndrome. Eleven patients were deceased, with a median age at death of 7.5 years. Conclusions: The classically described phenotype of patients with large-scale mtDNA deletions and early onset anemia is Pearson marrow-pancreas syndrome, characterized by sideroblastic anemia and exocrine pancreas dysfunction. Only a minority of our patients fulfill the original criteria of Pearson syndrome though. Involvement of other organs than the pancreas is more common. The clinical course vary, but multi-system impact is the rule and life-expectancy is low. Early onset anemia in patients with large-scale mtDNA deletions is most frequently not associated with exocrine pancreas dysfunction. Better knowledge of the phenotype is helpful for diagnosis and more accurate prognosis.
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| 2. |
- Björkman, Kristoffer, et al.
(författare)
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Phenotypic spectrum and clinical course of single large-scale mitochondrial DNA deletion disease in the paediatric population: a multicentre study.
- 2021
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 60:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- Background Large-scale mitochondrial DNA deletions (LMD) are a common genetic cause of mitochondrial disease and give rise to a wide range of clinical features. Lack of longitudinal data means the natural history remains unclear. This study was undertaken to describe the clinical spectrum in a large cohort of patients with paediatric disease onset. Methods A retrospective multicentre study was performed in patients with clinical onset <16 years of age, diagnosed and followed in seven European mitochondrial disease centres. Results A total of 80 patients were included. The average age at disease onset and at last examination was 10 and 31 years, respectively. The median time from disease onset to death was 11.5 years. Pearson syndrome was present in 21%, Kearns-Sayre syndrome spectrum disorder in 50% and progressive external ophthalmoplegia in 29% of patients. Haematological abnormalities were the hallmark of the disease in preschool children, while the most common presentations in older patients were ptosis and external ophthalmoplegia. Skeletal muscle involvement was found in 65% and exercise intolerance in 25% of the patients. Central nervous system involvement was frequent, with variable presence of ataxia (40%), cognitive involvement (36%) and stroke-like episodes (9%). Other common features were pigmentary retinopathy (46%), short stature (42%), hearing impairment (39%), cardiac disease (39%), diabetes mellitus (25%) and renal disease (19%). Conclusion Our study provides new insights into the phenotypic spectrum of childhood-onset, LMD-associated syndromes. We found a wider spectrum of more prevalent multisystem involvement compared with previous studies, most likely related to a longer time of follow-up.
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| 3. |
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| 4. |
- Fahnehjelm, Kristina Teär, et al.
(författare)
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Visual function, ocular motility and ocular characteristics in patients with mitochondrial complex I deficiency
- 2012
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Ingår i: Acta ophthalmologica. - : Wiley. - 1755-3768 .- 1755-375X. ; 90:1, s. 32-43
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Tidskriftsartikel (refereegranskat)abstract
- Abstract. Purpose: The aims of the present study were to investigate visual function, ocular motility and ocular characteristics in children and young adults with complex I deficiency. Material and Methods: In a prospective study with longitudinal follow-up, the visual and ocular outcome in 13 patients with deficiency in complex I [nicotine-amide adenine dinucleotide (NADH) dehydrogenase] in the mitochondrial respiratory chain is presented. The patients were diagnosed during 1995-2007 and assessed during 1997-2009 at a median age of 12.8 years (range 3.1-23.4). Results: Twelve of 13 patients had visual impairment and/or ocular pathology. Four of 10 patients who co-operated in visual assessment had a best corrected decimal visual acuity of A mutation in mitochondrial DNA. Only one patient had normal visual acuity and ocular outcome including refraction and visual fields. Follow-up time was median 3.0 years (range 0-11). Conclusion: Visual impairment, ocular motility problems and OA are common in children and young adults with complex I deficiency and should prompt the paediatric ophthalmologist to consider mitochondrial disorders.
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| 5. |
- Hikmat, Omar, et al.
(författare)
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Elevated cerebrospinal fluid protein in POLG-related epilepsy: Diagnostic and prognostic implications.
- 2018
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Ingår i: Epilepsia. - : Wiley. - 1528-1167 .- 0013-9580. ; 59:8, s. 1595-1602
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Tidskriftsartikel (refereegranskat)abstract
- Epilepsy is common in individuals with mutations in POLG, the gene encoding the catalytic subunit of the mitochondrial DNA polymerase gamma. Early recognition and aggressive seizure management are crucial for patient survival. Disruption of the blood-brain barrier (BBB) is implicated in various neurological disorders including epilepsy. The aim of this study was to assess whether POLG-related disease is associated with BBB dysfunction and what clinical implications this has for patients.Our retrospective study used data from 83 patients with pathogenic POLG mutations from 4 countries--Norway, Sweden, Finland, and the United Kingdom. Data were collected using a structured questionnaire. We used the presence of raised cerebrospinal fluid (CSF) protein and a raised CSF/serum ratio of albumin (Q-alb) to evaluate the integrity of the blood-CSF barrier.Raised CSF protein was found in 70% of patients (n = 58/83) and appeared to be associated with the most severe phenotypes. In those in whom it was measured, the Q-alb ratio was markedly elevated (n = 18). The majority of those with epilepsy (n = 50/66, 76%) had raised CSF protein, and this preceded seizure debut in 75% (n = 15/20). The median survival time from symptom onset for those with raised CSF protein was decreased (13 months) compared to those with normal CSF protein (32 months).Our results indicate that there is disruption of the BBB in POLG-related disease, as evidenced by a raised CSF protein and Q-alb ratio. We also find that raised CSF protein is a common finding in patients with POLG disease. Our data suggest that the presence of BBB dysfunction predicts a poorer outcome, and elevated CSF protein may therefore be an additional biomarker both for early diagnosis and to identify those at high risk of developing epilepsy.
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| 6. |
- Naess, Karin
(författare)
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Mitochondrial disease in children : from clinical presentation to genetic background
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mitochondrial disorders are amongst the most common groups of inborn errors of metabolism. They are caused by deficiencies in the final pathway of the cellular energy production, the mitochondrial respiratory chain. The disorders are clinically and genetically heterogeneous and the aetiology can be found in the mitochondrial, or in the nuclear genome. This thesis describes children with mitochondrial disorders, with focus on clinical symptoms, disease courses, biochemical abnormalities and genetic causes of disease. The research aimed to increase the understanding of the clinical phenotypes and pathophysiological mechanisms. We also aimed to identify novel disease-causing variants in mitochondrial (mtDNA), as well as nuclear, DNA in order to generate better tools for genetic counselling. In a study of patients with deficiencies of complex I of the mitochondrial respiratory chain, we observed a variety of clinical presentations. Early-onset of disease and muscle weakness were features in common. Developmental retardation and failure to thrive were seen in a majority of the patients. Causative variants in mtDNA were identified in six of the 11 patients. Leigh syndrome (LS) is a severe, neurodegenerative disease of early childhood. The genetic aetiology is heterogeneous. In a study of 25 children with LS, we observed early onset of disease, in 80% before six months of age. A subset of patients had a rapidly progressive disease and early death, 60% survived beyond the age of five years. Eight of the patients had a disease causing variant in mtDNA. The age ofonset, clinical symptoms or prognosis did not differ significantly between patients with mitochondrial and nuclear mutations in this cohort. A defect in the POLG gene was detected in a patient with Alpers syndrome. He had a heterozygous variant on one allele, the other allele being entirely deleted. The patient had rapid disease progression and died in a valproate induced liver failure. Massively parallel sequencing of the entire human genome and its implementation in clinical use is a diagnostic leap in the field of mitochondrial disorders. In a cohort of patients with combined deficiencies of the mitochondrial respiratory chain, 31 patients were subjected to whole genome/exome sequencing. A genetic diagnosis was established in 16 of these (52%), so far. Two novel gene defects were identified; SLC25A26 and COQ7. The latter gene encodes an enzyme of the Coenzyme Q (CoQ) biosynthesis. These disorders are responsive to CoQ10 treatment. We demonstrated a new mechanism of treatment using 2,4- dihydroxybenzoic acid in order to bypass the deficient step. In conclusion, paediatric mitochondrial disorders are severe, progressive and usually multisystemic. The most common symptoms are often non-specific and the diagnostic procedure is a challenge. The genetic aetiology is heterogeneous, a substantial proportion of the causative variants are found in mtDNA. The phenotype-genotype correlation is poor, making whole genome sequencing an excellent diagnostic tool.
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| 7. |
- Savvidou, Antri, et al.
(författare)
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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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Ingår i: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 45:2, s. 248-263
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Shahim, Pashtun, et al.
(författare)
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Cerebrospinal Fluid Brain Injury Biomarkers in Children: A Multicenter Study
- 2013
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Ingår i: Pediatric Neurology. - : Elsevier BV. - 0887-8994 .- 1873-5150. ; 80
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cerebrospinal fluid (CSF) biomarkers reflecting neuronal and astroglial injury, such as total tau (T-tau), glial flbrillary acidic protein (GFAP), and neurofilament light (NFL), have been extensively investigated in neurologic diseases in adults, but no large study has investigated these biomarkers in children. METHODS: This study presents a detailed evaluation of CFS T-tau, GFAP, NFL, and CSF:albumin ratio in a large cohort of pediatric patients. This is a retrospective multicenter study on pediatric patients aged <16 years (n = 607), where neuronal injury biomarkers T-tau, GFAP, NFL, and CSF albumin ratio were analyzed during 2000-2010 at the Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Sweden. The patients were grouped into eight categories: epilepsy, infectious and inflammatory central nervous system disorders, progressive encephalopathy, static encephalopathy, tumors, movement disorders, miscellaneous disorders, and a control group. RESULTS: T-tau, GFAP, and NFL were increased in progressive encephalopathy (P < 0.001), epilepsy (P < 0.001), and infectious and inflammatory central nervous system disorders (P < 0.001) compared with controls. T-tau was the biomarker with the highest diagnostic accuracy with the area under the curve of 0.83 (95% confidence interval (CI), 0.77-0.90; P < 0.0001) for progressive encephalopathy followed by epilepsy 0.80 (95% CI, 0.75-0.87; P < 0.0001). The combination of all four biomarkers further improved the area under the curve for the progressive encephalopathy 0.87 (95% CI, 0.77-0.89; P < 0.0001), followed by epilepsy 0.81 (95% CI, 0.74-0.80; P = 0.030). The combination of the biomarkers also separated progressive from static encephalopathy 0.88 (95% CI, 0.83-0.93; P < 0.0001). CONCLUSIONS: CSF T-tau, GFAP, and NFL are differently altered across different neurologic diseases in children. Importantly, the biomarker pattern distinguishes between progressive and static neurologic disorders. (c) 2013 Elsevier Inc. All rights reserved.
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| 9. |
- Sofou, Kalliopi, et al.
(författare)
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A multicenter study on Leigh syndrome: disease course and predictors of survival.
- 2014
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Ingår i: Orphanet journal of rare diseases. - : Springer Science and Business Media LLC. - 1750-1172. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Leigh syndrome is a progressive neurodegenerative disorder, associated with primary or secondary dysfunction of the mitochondrial oxidative phosphorylation. Despite the fact that Leigh syndrome is the most common phenotype of mitochondrial disorders in children, longitudinal natural history data is missing. This study was undertaken to assess the phenotypic and genotypic spectrum of patients with Leigh syndrome, characterise the clinical course and identify predictors of survival in a large cohort of patients.
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| 10. |
- Sofou, Kalliopi, et al.
(författare)
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Phenotype-genotype correlations in Leigh syndrome: new insights from a multicentre study of 96 patients.
- 2018
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Ingår i: Journal of medical genetics. - : BMJ. - 1468-6244 .- 0022-2593. ; 55:1, s. 21-27
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Tidskriftsartikel (refereegranskat)abstract
- Leigh syndrome is a phenotypically and genetically heterogeneous mitochondrial disorder. While some genetic defects are associated with well-described phenotypes, phenotype-genotype correlations in Leigh syndrome are not fully explored.We aimed to identify phenotype-genotype correlations in Leigh syndrome in a large cohort of systematically evaluated patients.We studied 96 patients with genetically confirmed Leigh syndrome diagnosed and followed in eight European centres specialising in mitochondrial diseases.We found that ataxia, ophthalmoplegia and cardiomyopathy were more prevalent among patients with mitochondrial DNA defects. Patients with mutations in MT-ND and NDUF genes with complex I deficiency shared common phenotypic features, such as early development of central nervous system disease, followed by high occurrence of cardiac and ocular manifestations. The cerebral cortex was affected in patients with NDUF mutations significantly more often than the rest of the cohort. Patients with the m.8993T>Gmutation in MT-ATP6 gene had more severe clinical and radiological manifestations and poorer disease outcome compared with patients with the m.8993T>Cmutation.Our study provides new insights into phenotype-genotype correlations in Leigh syndrome and particularly in patients with complex I deficiency and with defects in the mitochondrial ATP synthase.
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