Skip to main content
Erschienen in: Current Neurology and Neuroscience Reports 11/2019

01.11.2019 | Genetics (V. Bonifati, Section Editor)

Update on KMT2B-Related Dystonia

verfasst von: Michael Zech, Daniel D. Lam, Juliane Winkelmann

Erschienen in: Current Neurology and Neuroscience Reports | Ausgabe 11/2019

Einloggen, um Zugang zu erhalten

Abstract

Purpose of Review

To summarize the molecular and clinical findings of KMT2B-related dystonia (DYT-KMT2B), a newly identified genetic dystonia syndrome.

Recent Findings

Since first described in 2016, 66 different KMT2B-affecting variants, encompassing a set of frameshift, nonsense, splice-site, missense, and deletion mutations, have been reported in 76 patients. Most mutations are de novo and expected to mediate epigenetic dysregulation by inducing KMT2B haploinsufficiency. DYT-KMT2B is characterized phenotypically by limb-onset childhood dystonia that tends to spread progressively, resulting in generalized dystonia with cranio-cervical involvement. Co-occuring signs such as intellectual disability are frequently observed. Sustained response to deep brain stimulation (DBS), including restoration of independent ambulation, is seen in 93% (27/29) of patients.

Summary

DYT-KMT2B is emerging as a prevalent monogenic dystonia. Childhood-onset dystonia presentations should prompt a search for KMT2B mutations, preferentially via next-generation-sequencing and genomic-array technologies, to enable specific counseling and treatment. Prospective multicenter studies are desirable to establish KMT2B mutational status as a DBS outcome predictor.
Literatur
4.
Zurück zum Zitat •• Zech M, Boesch S, Maier EM, Borggraefe I, Vill K, Laccone F, et al. Haploinsufficiency of KMT2B, encoding the lysine-specific histone methyltransferase 2B, results in early-onset generalized dystonia. Am J Hum Genet. 2016;99(6):1377–87. https://doi.org/10.1016/j.ajhg.2016.10.010. In four independent families, this study identifies for the first time protein-truncating variants in the epigenetic regulator gene KMT2B as a cause of childhood-onset generalized dystonia. Based on the observations that (1) KMT2B mRNA levels were significantly decreased in patient-derived cells and (2) literature-reported whole-gene deletions of KMT2B were also associated with dystonia, the authors suggest haploinsufficiency as the most likely molecular mechanism of disease. CrossRefPubMedPubMedCentral •• Zech M, Boesch S, Maier EM, Borggraefe I, Vill K, Laccone F, et al. Haploinsufficiency of KMT2B, encoding the lysine-specific histone methyltransferase 2B, results in early-onset generalized dystonia. Am J Hum Genet. 2016;99(6):1377–87. https://​doi.​org/​10.​1016/​j.​ajhg.​2016.​10.​010. In four independent families, this study identifies for the first time protein-truncating variants in the epigenetic regulator gene KMT2B as a cause of childhood-onset generalized dystonia. Based on the observations that (1) KMT2B mRNA levels were significantly decreased in patient-derived cells and (2) literature-reported whole-gene deletions of KMT2B were also associated with dystonia, the authors suggest haploinsufficiency as the most likely molecular mechanism of disease. CrossRefPubMedPubMedCentral
5.
Zurück zum Zitat •• Meyer E, Carss KJ, Rankin J, Nichols JM, Grozeva D, Joseph AP, et al. Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia. Nat Genet. 2017;49(2):223–37. https://doi.org/10.1038/ng.3740. Published in parallel with the paper by Zech et al., this work decribes a large cohort of dystonia patients harboring protein-truncating, missense, and deletion mutations in KMT2B. The authors provide detailed genotypic and phenotypic data on 28 individuals with DYT-KMT2B, show that KMT2B mutations result in impaired expression of the dystonia-linked genes TOR1A and THAP1, and highlight deep brain stimulation as a promising treatment option for DYT-KMT2B. In addition, they elaborate on the broad spectrum of non-dystonic KMT2B-related symptoms and demonstrate that hypointense basal ganglia lesions can be seen on brain MRI scans of patients with DYT-KMT2B. CrossRefPubMed •• Meyer E, Carss KJ, Rankin J, Nichols JM, Grozeva D, Joseph AP, et al. Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia. Nat Genet. 2017;49(2):223–37. https://​doi.​org/​10.​1038/​ng.​3740. Published in parallel with the paper by Zech et al., this work decribes a large cohort of dystonia patients harboring protein-truncating, missense, and deletion mutations in KMT2B. The authors provide detailed genotypic and phenotypic data on 28 individuals with DYT-KMT2B, show that KMT2B mutations result in impaired expression of the dystonia-linked genes TOR1A and THAP1, and highlight deep brain stimulation as a promising treatment option for DYT-KMT2B. In addition, they elaborate on the broad spectrum of non-dystonic KMT2B-related symptoms and demonstrate that hypointense basal ganglia lesions can be seen on brain MRI scans of patients with DYT-KMT2B. CrossRefPubMed
12.
Zurück zum Zitat • Zech M, Jech R, Havrankova P, Fecikova A, Berutti R, Urgosik D, et al. KMT2B rare missense variants in generalized dystonia. Mov Disord. 2017;32(7):1087–91. https://doi.org/10.1002/mds.27026. This paper highlights the importance of accurate clinical interpretation of KMT2B missense variants, illustrated by clinico-genetic descriptions of three unrelated individuals with novel missense changes in KMT2B. CrossRefPubMed • Zech M, Jech R, Havrankova P, Fecikova A, Berutti R, Urgosik D, et al. KMT2B rare missense variants in generalized dystonia. Mov Disord. 2017;32(7):1087–91. https://​doi.​org/​10.​1002/​mds.​27026. This paper highlights the importance of accurate clinical interpretation of KMT2B missense variants, illustrated by clinico-genetic descriptions of three unrelated individuals with novel missense changes in KMT2B. CrossRefPubMed
14.
Zurück zum Zitat • Lange LM, Tunc S, Tennstedt S, Munchau A, Klein C, Assmann B, et al. A novel, in-frame KMT2B deletion in a patient with apparently isolated, generalized dystonia. Mov Disord. 2017;32(10):1495–7. https://doi.org/10.1002/mds.27137. In this manuscript, the first de novo in-frame deletion variant is reported, and the authors point out that KMT2B mutation should also be considered in the differential diagnosis of seemingly isolated dystonia. CrossRefPubMed • Lange LM, Tunc S, Tennstedt S, Munchau A, Klein C, Assmann B, et al. A novel, in-frame KMT2B deletion in a patient with apparently isolated, generalized dystonia. Mov Disord. 2017;32(10):1495–7. https://​doi.​org/​10.​1002/​mds.​27137. In this manuscript, the first de novo in-frame deletion variant is reported, and the authors point out that KMT2B mutation should also be considered in the differential diagnosis of seemingly isolated dystonia. CrossRefPubMed
16.
Zurück zum Zitat • Carecchio M, Invernizzi F, Gonzalez-Latapi P, Panteghini C, Zorzi G, Romito L, et al. Frequency and phenotypic spectrum of KMT2B dystonia in childhood: a single-center cohort study. Mov Disord. 2019. https://doi.org/10.1002/mds.27771 By identifying 14 novel dystonia patients with. KMT2B variants, this very recent study expands the mutational spectrum of DYT-KMT2B and provides supportive evidence for positive DBS response in DYT-KMT2B. CrossRefPubMed • Carecchio M, Invernizzi F, Gonzalez-Latapi P, Panteghini C, Zorzi G, Romito L, et al. Frequency and phenotypic spectrum of KMT2B dystonia in childhood: a single-center cohort study. Mov Disord. 2019. https://​doi.​org/​10.​1002/​mds.​27771 By identifying 14 novel dystonia patients with. KMT2B variants, this very recent study expands the mutational spectrum of DYT-KMT2B and provides supportive evidence for positive DBS response in DYT-KMT2B. CrossRefPubMed
22.
25.
Zurück zum Zitat • Kawarai T, Miyamoto R, Nakagawa E, Koichihara R, Sakamoto T, Mure H, et al. Phenotype variability and allelic heterogeneity in KMT2B-associated disease. Parkinsonism Relat Disord. 2018;52:55–61. https://doi.org/10.1016/j.parkreldis.2018.03.022. This study confirms high efficacy of DBS treatment in DYT-KMT2B and provides experimental evidence for a role of nonsense-mediated decay in the degregation of truncating variant-bearing KMT2B transcripts. CrossRefPubMed • Kawarai T, Miyamoto R, Nakagawa E, Koichihara R, Sakamoto T, Mure H, et al. Phenotype variability and allelic heterogeneity in KMT2B-associated disease. Parkinsonism Relat Disord. 2018;52:55–61. https://​doi.​org/​10.​1016/​j.​parkreldis.​2018.​03.​022. This study confirms high efficacy of DBS treatment in DYT-KMT2B and provides experimental evidence for a role of nonsense-mediated decay in the degregation of truncating variant-bearing KMT2B transcripts. CrossRefPubMed
37.
40.
Zurück zum Zitat • Barbagiovanni G, Germain PL, Zech M, Atashpaz S, Lo Riso P, D’Antonio-Chronowska A, et al. KMT2B is selectively required for neuronal transdifferentiation, and its loss exposes dystonia candidate genes. Cell Rep. 2018;25(4):988–1001. https://doi.org/10.1016/j.celrep.2018.09.067. This study elucidates the KMT2B-sensitive transcriptome required for transdifferentiation of murine embryonic fibroblasts into induced neuronal cells and tests the hypothesis that KMT2B target genes could represent novel disease candidates for dystonia. By interrogating 216 targets in whole-exome sequencing data from 225 dystonia patients, the authors prioritize variants in three candidates, namely NOL4, SLC35F1, and SLC40A1. CrossRefPubMedPubMedCentral • Barbagiovanni G, Germain PL, Zech M, Atashpaz S, Lo Riso P, D’Antonio-Chronowska A, et al. KMT2B is selectively required for neuronal transdifferentiation, and its loss exposes dystonia candidate genes. Cell Rep. 2018;25(4):988–1001. https://​doi.​org/​10.​1016/​j.​celrep.​2018.​09.​067. This study elucidates the KMT2B-sensitive transcriptome required for transdifferentiation of murine embryonic fibroblasts into induced neuronal cells and tests the hypothesis that KMT2B target genes could represent novel disease candidates for dystonia. By interrogating 216 targets in whole-exome sequencing data from 225 dystonia patients, the authors prioritize variants in three candidates, namely NOL4, SLC35F1, and SLC40A1. CrossRefPubMedPubMedCentral
Metadaten
Titel
Update on KMT2B-Related Dystonia
verfasst von
Michael Zech
Daniel D. Lam
Juliane Winkelmann
Publikationsdatum
01.11.2019
Verlag
Springer US
Erschienen in
Current Neurology and Neuroscience Reports / Ausgabe 11/2019
Print ISSN: 1528-4042
Elektronische ISSN: 1534-6293
DOI
https://doi.org/10.1007/s11910-019-1007-y

Weitere Artikel der Ausgabe 11/2019

Current Neurology and Neuroscience Reports 11/2019 Zur Ausgabe

Neurorehabilitation and Recovery (J Krakauer and T Kitago, Section Editors)

Music Therapy and Music-Based Interventions for Movement Disorders

Stroke (H.C. Diener, Section Editor)

Updates in the Treatment of Post-Stroke Pain

Stroke (H.C. Diener, Section Editor)

Stroke in the Young: a Global Update

Leitlinien kompakt für die Neurologie

Mit medbee Pocketcards sicher entscheiden.

Seit 2022 gehört die medbee GmbH zum Springer Medizin Verlag

Update Neurologie

Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert.