Decrease in the size of the myotonic dystrophy CTG repeat during transmission from parent to child: implications for genetic counselling and genetic anticipation.
Am J Med Genet
; 45(3): 401-7, 1993 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-8434633
ABSTRACT
Recently an unstable trinucleotide CTG repeat, located within the 3' untranslated region of a gene on 19q13.3 was discovered in kindreds with myotonic dystrophy (DM). The age-of-onset/severity of DM shows a good correlation with CTG repeat size, and pedigrees and data reported to date have shown a striking trend toward amplification of the size of the CTG repeat during transmission from parent to child. The amplification has been accepted as the biological explanation for anticipation in the clinical severity observed in many families with DM. In this paper we report on 3 families where CTG amplification decreased during transmission from parent to child. In one case there was a gene conversion event, while in the remaining 2 there was a simpler reduction in the size of the repeat length. The changes appear to have been accompanied by a reduction in clinical severity in the child when compared to the parent. These observations are discussed in terms of their clinical implications and the biases that may exist in much of the reported data.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sequências Repetitivas de Ácido Nucleico
/
Distrofia Miotônica
Tipo de estudo:
Diagnostic_studies
Limite:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Am J Med Genet
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
Canadá