SCA6 mutation analysis in a large cohort of the Japanese patients with late-onset pure cerebellar ataxia.
Spinocerebellar ataxia type 6 (SCA6) is caused by small CAG repeat expansion in the gene encoding the alpha1A-voltage-dependent-calcium channel subunit (CACNLIA4) on chromosome 19p13, and is a subgroup of the late-onset pure cerebellar ataxia (ADCA III). To investigate the prevalence of SCA6 in the Japanese, we analyzed this mutation in 23 families and 12 probands with ADCA III. The specificity and stability of the CAG repeat were examined in additional individuals and families with other miscellaneous dominant SCAs. The CAG expansion of SCA6 gene was exclusively observed in 12 of 23 families (52%) and 12 proband cases with ADCA III, but not in others. The CAG repeat was 21-33 in the disease-associated alleles (n=56), and 4-18 in normal alleles (n=1148). Expanded alleles were stable during transmission, and a significant inverse correlation for CAG repeat number with age at onset was noted. Our results indicate that SCA6 shares approximately half of the ADCA III in the Japanese, and that gene mutations causing the remaining, have yet to be identified.
Yabe
I
I
Department of Neurology, Hokkaido University School of Medicine, Sapporo, Japan.
Sasaki
H
H
Matsuura
T
T
Takada
A
A
Wakisaka
A
A
Suzuki
Y
Y
Fukazawa
T
T
Hamada
T
T
Oda
T
T
Ohnishi
A
A
Tashiro
K
K
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000483:Alleles; D000067696:Ataxin-1; D000067528:Ataxins; D015220:Calcium Channels / Q000235:genetics*; D002524:Cerebellar Ataxia / Q000235:genetics*; D002888:Chromosomes, Human, Pair 19; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D010375:Pedigree; D011506:Proteins / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D020864:Calcium Channels, N-Type
D000067696:Ataxin-1; D000067528:Ataxins; D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011506:Proteins; C000593749:ATXN1 protein, human; C105656:CACNA1A protein, human; D020864:Calcium Channels, N-Type