Somatic heterogeneity of the CTG repeat in myotonic dystrophy is age and size dependent

L. J C Wong, T. Ashizawa, D. G. Monckton, C. T. Caskey, Carolyn (Sue) Richards

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The most common form of adult muscular dystrophy, myotonic dystrophy (DM), is caused by the abnormal expansion of the CTG repeat, located in the 3' UTR of the DM gene. The expanded-CTG allele often presents as a diffused band on Southern blot analysis, suggesting somatic mosaicism. In order to study the somatic instability of the CTG repeat, we have investigated the dynamics of the size heterogeneity of the CTG expansion. Size heterogeneity is shown as a smear on Southern blot and is measured by the midpeak-width ratio of the expanded allele to the normal sized allele. The ratio is also corrected for compression in the higher-molecular-weight region. It is found that the size heterogeneity of the expanded-CTG repeats, of 173 DM patients, correlates well with the age of the patient (r = .81, P

Original languageEnglish (US)
Pages (from-to)114-122
Number of pages9
JournalAmerican Journal of Human Genetics
Issue number1
Publication statusPublished - 1995
Externally publishedYes


ASJC Scopus subject areas

  • Genetics

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