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            : Trapezius myotonia percussion sign in myotonic dystrophy type 2

Johnson, Nicholas E.; Heatwole, Chad

doi:10.1212/wnl.0b013e318296e905

Cited by 4 publications

(5 citation statements)

References 2 publications

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“…2 ). On follow-up examination, the affected parent had mild features of DM2, including the classical finding of percussion myotonia [ 10 ]. This DM2 RE was not detected in any of their cousins in the broader family, regardless of ASD status, and notably did not segregate with their father who had ASD.…”

Section: Resultsmentioning

confidence: 99%

Unexpected diagnosis of myotonic dystrophy type 2 repeat expansion by genome sequencing

et al. 2022

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Several neurological disorders, such as myotonic dystrophy are caused by expansions of short tandem repeats (STRs) which can be difficult to detect by molecular tools. Methodological advances have made repeat expansion (RE) detection with whole genome sequencing (WGS) feasible. We recruited a multi-generational family (family A) ascertained for genetic studies of autism spectrum disorder. WGS was performed on seven children from four nuclear families from family A and analyzed for REs of STRs known to cause neurological disorders. We detected an expansion of a heterozygous intronic CCTG STR in CNBP in two siblings. This STR causes myotonic dystrophy type 2 (DM2). The expansion did not segregate with the ASD phenotype. Repeat-primed PCR showed that the DM2 CCTG motif was expanded above the pathogenic threshold in both children and their mother. On subsequent examination, the mother had mild features of DM2. We show that screening of STRs in WGS datasets has diagnostic utility, both in the clinical and research domain, with potential management and genetic counseling implications.

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Section: Resultsmentioning

confidence: 99%

Unexpected diagnosis of myotonic dystrophy type 2 repeat expansion by genome sequencing

et al. 2022

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“…Im Vergleich mit der DM1 ist der Verlauf der DM2 milder ausgeprägt [46]. Die muskuläre Beteiligung beginnt in der proximalen Muskulatur mit Paresen und Myalgien [47]. Die Myotonie ist meist nur sehr gering ausgeprägt, proximal betont und klinisch und elektromyografisch schwieriger nachzuweisen als bei der DM1 [47].…”

Section: Haut-und Hautanhangsgebildeunclassified

“…Die muskuläre Beteiligung beginnt in der proximalen Muskulatur mit Paresen und Myalgien [47]. Die Myotonie ist meist nur sehr gering ausgeprägt, proximal betont und klinisch und elektromyografisch schwieriger nachzuweisen als bei der DM1 [47]. Ein klinischer Hinweis auf eine proximale Myotonie ist das "Trapezius myotonia percussion sign" (Beklopfen des Trapeziusoberrands löst eine klinisch myotone Reaktion aus) [47].…”

Section: Haut-und Hautanhangsgebildeunclassified

“…Die Myotonie ist meist nur sehr gering ausgeprägt, proximal betont und klinisch und elektromyografisch schwieriger nachzuweisen als bei der DM1 [47]. Ein klinischer Hinweis auf eine proximale Myotonie ist das "Trapezius myotonia percussion sign" (Beklopfen des Trapeziusoberrands löst eine klinisch myotone Reaktion aus) [47]. Bis zu zwei Drittel der Patienten entwickeln zumindest einmal im Verlauf behandlungsbedürftige Myalgien, die sich meist unter Bewegung bessern [48].…”

Section: Haut-und Hautanhangsgebildeunclassified

“…Vereinzelt findet sich eine Pseudohypertrophie der Waden. Fast alle Patienten haben eine Katarakt [47]. Kognitive Defizite sind im Vergleich zur DM1 seltener und nicht so ausgeprägt [49].…”

Section: Haut-und Hautanhangsgebildeunclassified

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Myotone Dystrophien: Klinik, Pathogenese, Diagnostik und Therapie

Finsterer

Rudnik‐Schöneborn

2015

Fortschr Neurol Psychiatr

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The autosomal-dominant myotonic dystrophies dystrophia myotonica type-1 (DM1, Curschmann-Steinert disease) and dystrophia myotonica type-2 (DM2, proximal myotonic myopathy (PROMM)), are, contrary to the non-dystrophic myotonias, progressive multisystem disorders. DM1 and DM2 are the most frequent of the muscular dystrophies. In both diseases the skeletal muscle is the most severely affected organ (weakness, wasting, myotonia, myalgia). Additionally, they manifest in the eye, heart, brain, endocrine glands, gastrointestinal tract, skin, skeleton, and peripheral nerves. Phenotypes of DM1 may be classified as congenital, juvenile, classical, or late onset. DM2 is a disorder of the middle or older age and usually has a milder course compared to DM1. DM1 is due to a CTG-repeat expansion > 50 repeats in the non-coding 3' UTR of the DMPK-gene. DM2 is caused by a CCTG-repeat expansion to 75 - 11 000 repeats in intron-1 of the CNBP/ZNF9 gene. Mutant pre-mRNAs of both genes aggregate within the nucleus (nuclear foci), which sequester RNA-binding proteins and result in an abnormal protein expression via alternative splicing in downstream effector genes (toxic RNA diseases). Other mechanisms seem to play an additional pathogenetic role. Clinical severity of DM1 increases from generation to generation (anticipation). The higher the repeat expansion the more severe the DM1 phenotype. In DM2 severity of symptoms and age at onset do not correlate with the expansion size. Contrary to DM2, there is a congenital form and anticipation in DM1.

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A role for cannabinoids in the treatment of myotonia? Report of compassionate use in a small cohort of patients

et al. 2019

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Teaching Video Neuro Images : Trapezius myotonia percussion sign in myotonic dystrophy type 2

Cited by 4 publications

References 2 publications

Unexpected diagnosis of myotonic dystrophy type 2 repeat expansion by genome sequencing

Unexpected diagnosis of myotonic dystrophy type 2 repeat expansion by genome sequencing

Myotone Dystrophien: Klinik, Pathogenese, Diagnostik und Therapie

A role for cannabinoids in the treatment of myotonia? Report of compassionate use in a small cohort of patients

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