A novel long and unstable CAG/CTG trinucleotide repeat on chromosome 17q.
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.
Ikeuchi
T
T
Department of Neurology, Niigata University, Japan.
Sanpei
K
K
Takano
H
H
Sasaki
H
H
Tashiro
K
K
Cancel
G
G
Brice
A
A
Bird
T D
TD
Schellenberg
G D
GD
Pericak-Vance
M A
MA
Welsh-Bohmer
K A
KA
Clark
L N
LN
Wilhelmsen
K
K
Tsuji
S
S
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*