Document Detail

Further evidence for a major ancient mutation underlying myotonic dystrophy from linkage disequilibrium studies in the Japanese population.
MedLine Citation:
PMID:  9852676     Owner:  NLM     Status:  MEDLINE    
The myotonic dystrophy (DM) mutation is an unstable (CTG)n repeat, present at a copy number of 5-37 repeats on normal chromosomes but amplified to 50-3000 copies on DM chromosomes. Previous findings in Caucasian populations of a DM founder chromosome raise a question about the molecular events involved in the expansion mutation. To investigate whether a founder chromosome for the DM mutation exists in the Japanese population, we genotyped families using polymorphic markers near the (CTG)n repeat region and constructed haplotypes. Six different haplotypes were found and DM alleles were always haplotype A. To find an origin of the (CTG)n repeat mutation and to investigate the mechanism of the expansion mutation in the Japanese population we have studied 90 Japanese DM families comprising 190 affected and 130 unaffected members. The results suggest that a few common ancestral mutations in both Caucasian and Japanese populations have originated by expansion of an ancestral n = 5 repeat to n = 19-37 copies. These data support multistep models of triplet repeat expansion that have been proposed for both DM and Friedreich's ataxia.
H Yamagata; M Nakagawa; K Johnson; T Miki
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of human genetics     Volume:  43     ISSN:  1434-5161     ISO Abbreviation:  J. Hum. Genet.     Publication Date:  1998  
Date Detail:
Created Date:  1999-01-13     Completed Date:  1999-01-13     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9808008     Medline TA:  J Hum Genet     Country:  JAPAN    
Other Details:
Languages:  eng     Pagination:  246-9     Citation Subset:  IM    
Department of Geriatric Medicine, Ehime University School of Medicine, Japan.
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MeSH Terms
Asian Continental Ancestry Group / genetics
Gene Frequency
Linkage Disequilibrium*
Myotonic Dystrophy / genetics*
Polymorphism, Genetic
Protein-Serine-Threonine Kinases / genetics
Repetitive Sequences, Nucleic Acid
Reg. No./Substance:
EC 2.7.1.-/myotonic dystrophy protein kinase; EC Kinases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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