Clinical Significance of CTG Repeat Expansion in Korean Myotonic Dystrophy Patients.
- Author:
Byung Ok CHOI
1
;
Il Nam SUNWOO
;
Seung Min KIM
;
Jin Sung LEE
;
Eun Kyung LEE
;
Kee Duk PARK
;
Keun Ho JUNG
;
Joon Shik MOON
Author Information
1. Department of Neurology, College of Medicine Yonsei University.
- Publication Type:Original Article
- Keywords:
Myotonic Dystrophy;
Clinical Significance;
CTG Repeat Expansion;
Myotonic Discharge;
Anticipation
- MeSH:
Adult;
Age of Onset;
Anticipation, Genetic;
Base Sequence;
Blotting, Southern;
DNA;
Genetic Counseling;
Humans;
Molecular Biology;
Muscular Dystrophies;
Myotonic Dystrophy*;
Polymerase Chain Reaction;
Trinucleotide Repeats
- From:Journal of the Korean Neurological Association
1999;17(4):548-553
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Myotonic dystrophy is the most common type of muscular dystrophy affecting adults, associated with the expansion of triplet repeat DNA sequences. A hallmark of the inherited disease with trinucleotide repeat DNA expansion is the clinical and genetic anticipation. The copy numbers of the CTG repeat are known to be related to the severity and the onset age of clinical symptoms. METHODS: The copy numbers of the CTG repeats were determined using PCR amplification and Southern blotting. The clinical manisfestations of 34 patients from 14 families who had the CTG repeat expansion were evaluated based on the muscular disability rating scale and the electrophysiological study. RESULTS: There was a significant positive correlation between the clinical scores and the size of the amplification of trinucleotide repeat, and a negative correlation with the age of onset. In 9 patients with copy numbers of CTG repeats between 61 and 100, 8 cases were asymptomatic and myotonic discharges were not seen in 71% of patients. Larger expanded bands, earlier onset, and worse symptoms were evident with each successive generation. CONCLUSIONS: Molecular genetic analysis with CTG repeat expansion might be useful in the detection and the genetic counseling of myotonic dystrophy patients.
