These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Evidence for a mechanism predisposing to intergenerational CAG repeat instability in spinocerebellar ataxia type I.
    Author: Chung MY, Ranum LP, Duvick LA, Servadio A, Zoghbi HY, Orr HT.
    Journal: Nat Genet; 1993 Nov; 5(3):254-8. PubMed ID: 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.
    [Abstract] [Full Text] [Related] [New Search]