Myotonic Dystrophy – Unity in Diversity

Česká verzia

Authors: S. Voháňka
Authors place of work: Neurologická klinika LF MU a FN Brno
Published in the journal: Cesk Slov Neurol N 2017; 80/113(3): 255-265
Category: Minimonography
doi: https://doi.org/10.14735/amcsnn2017255

Summary

Myotonic dystrophy is the most frequent muscular dystrophy of adult age characterised by muscle weakness, myotonia, cataracts, and autosomal dominant inheritance. The disease is caused by trinucleotide expansion in the DMPK gene in case of myotonic dystrophy type 1 (MD1) and tetranucleotide expansion in the CNBP/ZNF9 gene in myotonic dystrophy type 2 (MD2). The accumulation of RNA transcripts and its toxicity leads to dysregulation of many other genes, providing a clue for understanding of the broad clinical spectrum of the disease. MD1 manifests from birth (congenital) to adulthood. Severity and time of onset correlate with the number of repeats. On the contrary, MD2 is a disease with an onset during adult age only. Localisation of muscle weakness is also diff erent; the facial muscles, paraspinal, distal muscles of upper and lower limbs are aff ected in case of MD1 and the proximal muscles, esp. of lower limbs are involved in patients suff ering from MD2 – this localisation determined the former name: proximal myotonic myopathy. In contrast to MD1 that has worldwide prevalence, MD2 is predominantly restricted to middle and northern Europe. The heart conduction system (arrhythmias) is aff ected in patients with either type of the disease. In general, the impact of the disease is more severe in patients with MD1 than in MD2. Due to involvement of many systems, a multidisciplinary approach and team should be involved in the management of these patients.

Key words:
myotonic dystrophy type 1 – myotonic dystrophy type 2 – proximal myotonic myopathy

The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study.

The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers.

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