Submitted by: Francisco Gomez, MD
Edited by: Francisco Gomez, MD
Roy B, Wu Q, Whitaker CH, Felice KJ. Myotonic Muscular Dystrophy Type 2 in CT, USA: A Single-Center Experience With 50 Patients. J Clin Neuromuscul Dis
. 2021;22(3):135-146. doi:10.1097/CND.0000000000000340
Myotonic muscular dystrophy type 2 (DM2) is a an autosomal dominant genetic disease stemming from expansion of the first intron of the Cellular Nucleic acid Binding Protein (CNBP) gene which encodes for a zinc finger protein. This disease tends to course with wasting muscle weakness, characteristic myotonia, and cataracts.
The authors report a 27 year, single center case series involving 50 patients diagnosed with Myotonic Dystrophy type 2, reporting incidence and prevalence of several findings:
Age of onset ranged 15-72 years, with an average time from clinical debut to diagnosis of 7.4 years, furthermore:
• 18% presented with clinical myotonia, however, electromyographic myotonia was found in 97% of patients.
• 62% debuted with proximal extremity weakness.
• 30% presented generalized weakness while 20% exhibited no weakness at all.
• There was no correlation between number of repeats and pathologic changes, however there was a correlation noted between degree of muscle weakness and muscle pathologic changes.
• A 1% yearly decline in Medical Research Council scores was observed in 21 patients followed for 2 or more years.