title: A novel long and unstable CAG/CTG trinucleotide repeat on chromosome 17q.
abstract: Using the direct identification of repeat expansion and cloning technique, we cloned a novel long CAG/CTG trinucleotide repeat on chromosome 17. Using radiation hybrid panels, the CAG/CTG repeat was mapped to chromosome 17q. The CAG/CTG repeat is highly polymorphic, with a heterozygosity of 85%, and exhibits a bimodal distribution (allele S, 10-26 repeat units, and allele L, 50-92 repeat units). The CAG/CTG repeat of allele L exhibited intergenerational instabilities, which are more prominent in maternal transmission than in paternal transmission. Analyses of Northern blot and RT-PCR indicate that the repeat is transcribed. Although the size of the CAG/CTG repeat of allele L is within the range of the expanded CAG repeat of disease-causing genes, we did not detect any association of allele L with various neurodegenerative diseases, including frontotemporal dementia and parkinsonism, mapped to 17q21-q23.
authors.affiliation: Department of Neurology, Niigata University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ikeuchi
authors.forename: K
authors.initials: K
authors.lastname: Sanpei
authors.forename: H
authors.initials: H
authors.lastname: Takano
authors.forename: H
authors.initials: H
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Tashiro
authors.forename: G
authors.initials: G
authors.lastname: Cancel
authors.forename: A
authors.initials: A
authors.lastname: Brice
authors.forename: T D
authors.initials: TD
authors.lastname: Bird
authors.forename: G D
authors.initials: GD
authors.lastname: Schellenberg
authors.forename: M A
authors.initials: MA
authors.lastname: Pericak-Vance
authors.forename: K A
authors.initials: KA
authors.lastname: Welsh-Bohmer
authors.forename: L N
authors.initials: LN
authors.lastname: Clark
authors.forename: K
authors.initials: K
authors.lastname: Wilhelmsen
authors.forename: S
authors.initials: S
authors.lastname: Tsuji
mesh_terms: D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D005799:Genes, Dominant; D006801:Humans; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic / Q000235:genetics; D013132:Spinocerebellar Degenerations / Q000235:genetics; D018911:Trinucleotide Repeats / Q000235:genetics*