Survival and CTG repeat expansion in adults with myotonic dystrophy type 1

Muscle Nerve. 2011 May;43(5):648-51. doi: 10.1002/mus.21934.

Abstract

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.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cohort Studies
  • Cytosine* / chemistry
  • Female
  • Follow-Up Studies
  • Guanine* / chemistry
  • Humans
  • Male
  • Middle Aged
  • Myotonic Dystrophy / genetics
  • Myotonic Dystrophy / metabolism
  • Myotonic Dystrophy / mortality
  • Survival Rate / trends
  • Thymine* / chemistry
  • Trinucleotide Repeat Expansion / genetics*
  • Young Adult

Substances

  • Guanine
  • Cytosine
  • Thymine