Abstract
Introduction/Aims: Although the extent of muscle weakness and organ complications has not been well studied in patients with late-onset myotonic dystrophy type 1 (DM1), adult-onset DM1 is associated with severe muscle involvement and possible life-threatening cardiac and respiratory complications. In this study we aimed to compare the clinical phenotype of adult-onset vs late-onset DM1, focusing on the prevalence of cardiac, respiratory, and muscular involvement. Methods: Data were prospectively collected in the Dutch DM1 registry. Results: Two hundred seventy-five adult-onset and 66 late-onset DM1 patients were included. Conduction delay on electrocardiogram was present in 123 of 275 (45%) adult-onset patients, compared with 24 of 66 (36%) late-onset patients (P =.218). DM1 subtype did not predict presence of conduction delay (odds ratio [OR] 0.706; confidence interval [CI] 0.405 to 1.230, P =.219). Subtype did predict indication for noninvasive ventilation (NIV) (late onset vs adult onset: OR, 0.254; CI, 0.104 to 0.617; P =.002) and 17% of late-onset patients required NIV compared with 40% of adult-onset patients. Muscular Impairment Rating Scale (MIRS) scores were significantly different between subtypes (MIRS 1 to 3 in 66% of adult onset vs 100% of late onset [P <.001]), as were DM1-activ C scores (67 ± 21 in adult onset vs 87 ± 15 in late onset; P <.001). Discussion: Although muscular phenotype was milder in late-onset compared with adult-onset DM1, the prevalence of conduction delay was comparable. Moreover, subtype was unable to predict the presence of cardiac conduction delay. Although adult-onset patients had an increased risk of having an NIV indication, 17% of late-onset patients required NIV. Despite different muscular phenotypes, screening for multiorgan involvement should be equally thorough in late-onset as in adult-onset DM1.
Original language | English |
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Pages (from-to) | 130-137 |
Number of pages | 8 |
Journal | Muscle & Nerve |
Volume | 67 |
Issue number | 2 |
Early online date | 9 Dec 2022 |
DOIs | |
Publication status | Published - Feb 2023 |
Keywords
- Cardiomyopathy
- Conduction delay
- Muscle weakness
- Myotonic dystrophy
- Noninvasive ventilation
- Phenotype