Introduction: An association is observed between the severity of myotonic dystrophy type 1 (DM1) and the genetic abnormality of cytosine-thymine-guanine (CTG) repeat expansion. It is unknown whether an association exists between survival and CTG repeat expansion.
Methods: In an adult 406-patient DM1 cohort, the phenotype, including survival age, was evaluated in relation to CTG repeat expansion.
Results: At study entry, age was 42 ± 12 (range 18-78) years, with a CTG repeat length of 629 ± 386 (range 54-1965). An inverse correlation was observed between CTG repeat length and the age at onset and younger DM1 phenotype. Over a follow-up of 9.2 ± 3.1 years, 118 (29.1%) patients died, including 60 of neuromuscular respiratory failure, 41 of cardiac causes, and 17 of non-neuromuscular, non-cardiac causes. There was an inverse relationship between all-cause survival and CTG length (relative risk 5.4 per log repeat, 95% confidence interval 2.9-10.2, P < 0.001).
Conclusion: The data demonstrate a genotype-mortality association in DM1.
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http://dx.doi.org/10.1002/mus.21934 | DOI Listing |
JACC Clin Electrophysiol
January 2025
Section of Cardiac Electrophysiology, Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Background: Literature on the prevalence and management of atrial arrhythmias in patients with myotonic muscular dystrophy type 1 (MMD1) or myotonic muscular dystrophy type 2 (MMD2) is limited.
Objectives: This study sought to describe incidence, prevalence, and predictors of atrial fibrillation (AF) and atrial flutter (AFL) in a contemporary cohort of patients with myotonic muscular dystrophy (MMD).
Methods: Associations between patient factors and incident AF/AFL were analyzed in patients with MMD referred for routine electrophysiology evaluation between January 2013 and September 2023.
J Clin Invest
January 2025
Center for Inherited Myology Research, Virginia Commonwealth University, Richmond, United States of America.
Background: Myotonic dystrophy type 1 (DM1) is a multisystemic, CTG repeat expansion disorder characterized by a slow, progressive decline in skeletal muscle function. A biomarker correlating RNA mis-splicing, the core pathogenic disease mechanism, and muscle performance is crucial for assessing response to disease-modifying interventions. We evaluated the Myotonic Dystrophy Splice Index (SI), a composite RNA splicing biomarker incorporating 22 disease-specific events, as a potential biomarker of DM1 muscle weakness.
View Article and Find Full Text PDFGenetics
January 2025
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA.
Mismatch repair (MMR) is a highly conserved DNA repair pathway that recognizes mispairs that occur spontaneously during DNA replication and coordinates their repair. In Saccharomyces cerevisiae, Msh2-Msh3 and Msh2-Msh6 initiate MMR by recognizing and binding insertion deletion loops (in/dels) up to ∼ 17 nucleotides (nt.) and base-base mispairs, respectively; the two complexes have overlapping specificity for small (1-2 nt.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Program in Genetics, Molecular, and Cellular Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111.
CAG/CTG repeats are prone to expansion, causing several inherited human diseases. The initiating sources of DNA damage which lead to inaccurate repair of the repeat tract to cause expansions are not fully understood. Expansion-prone CAG/CTG repeats are actively transcribed and prone to forming stable R-loops with hairpin structures forming on the displaced single-stranded DNA (S-loops).
View Article and Find Full Text PDFJACC Case Rep
December 2024
Cardiology Unit, Policlinico di Modena Hospital, Modena, Italy.
Myotonic dystrophy type 1 (MD1) is the most common form of muscular dystrophy in adults. MD1 is caused by the expansion of CTG repeats in the DMPK gene and affects various organs beyond muscles. We present a case of a patient with MD1 exhibiting features of metabolic syndrome (MetS), including insulin resistance and dyslipidemia.
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