| 1. |
- Fresard, Laure, et al.
(author)
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Identification of rare-disease genes using blood transcriptome sequencing and large control cohorts
- 2019
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In: Nature Medicine. - : NATURE PUBLISHING GROUP. - 1078-8956 .- 1546-170X. ; 25:6, s. 911-919
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Journal article (peer-reviewed)abstract
- It is estimated that 350 million individuals worldwide suffer from rare diseases, which are predominantly caused by mutation in a single gene(1). The current molecular diagnostic rate is estimated at 50%, with whole-exome sequencing (WES) among the most successful approaches(2-5). For patients in whom WES is uninformative, RNA sequencing (RNA-seq) has shown diagnostic utility in specific tissues and diseases(6-8). This includes muscle biopsies from patients with undiagnosed rare muscle disorders(6,9), and cultured fibroblasts from patients with mitochondrial disorders(7). However, for many individuals, biopsies are not performed for clinical care, and tissues are difficult to access. We sought to assess the utility of RNA-seq from blood as a diagnostic tool for rare diseases of different pathophysiologies. We generated whole-blood RNA-seq from 94 individuals with undiagnosed rare diseases spanning 16 diverse disease categories. We developed a robust approach to compare data from these individuals with large sets of RNA-seq data for controls (n = 1,594 unrelated controls and n = 49 family members) and demonstrated the impacts of expression, splicing, gene and variant filtering strategies on disease gene identification. Across our cohort, we observed that RNA-seq yields a 7.5% diagnostic rate, and an additional 16.7% with improved candidate gene resolution.
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| 2. |
- Ng, Bobby G, et al.
(author)
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ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients.
- 2016
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In: Human Mutation. - : Hindawi Limited. - 1059-7794.
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Journal article (peer-reviewed)abstract
- Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over one hundred genes leading to impaired protein or lipid glycosylation. ALG1 encodes a β1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate (DLO) required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date thirteen mutations in eighteen patients from fourteen families have been described with varying degrees of clinical severity. We identified and characterized thirty-nine previously unreported cases of ALG1-CDG from thirty-two families and add twenty-six new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all twenty-seven patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder. This article is protected by copyright. All rights reserved.
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| 3. |
- Meyer, Esther, et al.
(author)
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Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia.
- 2017
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In: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 49
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Journal article (peer-reviewed)abstract
- Histone lysine methylation, mediated by mixed-lineage leukemia (MLL) proteins, is now known to be critical in the regulation of gene expression, genomic stability, cell cycle and nuclear architecture. Despite MLL proteins being postulated as essential for normal development, little is known about the specific functions of the different MLL lysine methyltransferases. Here we report heterozygous variants in the gene KMT2B (also known as MLL4) in 27 unrelated individuals with a complex progressive childhood-onset dystonia, often associated with a typical facial appearance and characteristic brain magnetic resonance imaging findings. Over time, the majority of affected individuals developed prominent cervical, cranial and laryngeal dystonia. Marked clinical benefit, including the restoration of independent ambulation in some cases, was observed following deep brain stimulation (DBS). These findings highlight a clinically recognizable and potentially treatable form of genetic dystonia, demonstrating the crucial role of KMT2B in the physiological control of voluntary movement.
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| 4. |
- Rubinstein, Yaffa R., et al.
(author)
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The case for open science : rare diseases
- 2020
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In: JAMIA Open. - : Oxford University Press (OUP). - 2574-2531. ; 3:3, s. 472-486
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Research review (peer-reviewed)abstract
- The premise of Open Science is that research and medical management will progress faster if data and knowledge are openly shared. The value of Open Science is nowhere more important and appreciated than in the rare disease (RD) community. Research into RDs has been limited by insufficient patient data and resources, a paucity of trained disease experts, and lack of therapeutics, leading to long delays in diagnosis and treatment. These issues can be ameliorated by following the principles and practices of sharing that are intrinsic to Open Science. Here, we describe how the RD community has adopted the core pillars of Open Science, adding new initiatives to promote care and research for RD patients and, ultimately, for all of medicine. We also present recommendations that can advance Open Science more globally.
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| 5. |
- Nmezi, Bruce, et al.
(author)
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Genomic deletions upstream of lamin B1 lead to atypical autosomal dominant leukodystrophy
- 2019
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In: NEUROLOGY-GENETICS. - 2376-7839. ; 5:1
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Journal article (peer-reviewed)abstract
- Objective Clinical, radiologic, and molecular analysis of patients with genomic deletions upstream of the LMNB1 gene.Methods Detailed neurologic, MRI examinations, custom array comparative genomic hybridization (aCGH) analysis, and expression analysis were performed in patients at different clinical centers. All procedures were approved by institutional review boards of the respective institutions.Results Five patients from 3 independent families presented at ages ranging from 32 to 52 years with neurologic symptoms that included progressive hypophonia, upper and lower limb weakness and spasticity, and cerebellar dysfunction and MRIs characterized by widespread white matter alterations. Patients had unique nonrecurrent deletions upstream of the LMNB1, varying in size from 250 kb to 670 kb. Deletion junctions were embedded in repetitive elements. Expression analysis revealed increased LMNB1 expression in patient cells.Conclusions Our findings confirmed the association between LMNB1 upstream deletions and leukodystrophy previously reported in a single family, expanding the phenotypic and molecular description of this condition. Although clinical and radiologic features overlapped with those of autosomal dominant leukodystrophy because of LMNB1 duplications, patients with deletions upstream of LMNB1 had an earlier age at symptom onset, lacked early dysautonomia, and appeared to have lesser involvement of the cerebellum and sparing of the spinal cord diameter on MRI. aCGH analysis defined a smaller minimal critical region required for disease causation and revealed that deletions occur at repetitive DNA genomic elements. Search for LMNB1 structural variants (duplications and upstream deletions) should be an integral part of the investigation of patients with autosomal dominant adult-onset leukodystrophy.
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