Evidence for a mechanism predisposing to intergenerational CAG repeat instability in spinocerebellar ataxia type I.
Nat Genet
; 5(3): 254-8, 1993 Nov.
Article
em En
| MEDLINE
| ID: mdl-8275090
ABSTRACT
Spinocerebellar ataxia type I (SCAI) is an autosomal dominant neurodegenerative disease caused by the expansion of a CAG trinucleotide repeat on chromosome 6p. Normal alleles range from 19-36 repeats while SCA1 alleles contain 43-81 repeats. We now show that in 63% of paternal transmissions, an increase in repeat number is observed, whereas 69% of maternal transmissions showed no change or a decrease in repeat number. Sequence analysis of the repeat from 126 chromosomes reveals an interrupted repeat configuration in 98% of the unexpanded alleles but a contiguous repeat (CAG)n configuration in 30 expanded alleles from seven SCA1 families. This indicates that the repeat instability in SCA1 is more complex than a simple variation in repeat number and that the loss of an interruption predisposes the SCA1 (CAG)n to expansion.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sequências Repetitivas de Ácido Nucleico
/
Degenerações Espinocerebelares
Limite:
Humans
Idioma:
En
Revista:
Nat Genet
Assunto da revista:
GENETICA MEDICA
Ano de publicação:
1993
Tipo de documento:
Article