[Expansion of triplet repeat and neurodegenerative disorders].
Recent studies on human genetic analysis have revealed that there is hitherto unknown category of genomic abnormality in human genetic diseases; an abnormal expansion of trinucleotide repeat. For example, Huntington's disease is caused by the CAG expansion to more than 40 in IT15 gene Up to the present, we have 7 disorders which are revealed to be apparently caused by the triple repeat expansion: fragile X syndrome (two types), myotonic dystrophy, Huntington's disease, spinocerebellar atrophy type 1, dentatorubropallidoluysian atrophy and bulbo-spinal muscular atrophy. In this symposium, I would like to show first a clear inverse relationship between a length of CAG repeat and the age at onset in each Huntington's disease patient in Japan. Next, we would like to review and discuss on 1) the possible role of normal trinucleotide repeat in human gene, 2) the mechanisms for expansion of triplet repeat and for instability of the repeat length, and 3) the actual mechanism for neuronal cell death related to the expansion of triplet repeat.
Kanazawa
I
I
Department of Neurology, University of Tokyo.
D016923:Cell Death; D005799:Genes, Dominant; D006801:Humans; D006816:Huntington Disease / Q000235:genetics*; D018598:Minisatellite Repeats; D009474:Neurons