Spinocerebellar ataxia type 6. Molecular and clinical features of 35 Japanese patients including one homozygous for the CAG repeat expansion

Spinocerebellar ataxia type 6 (SCA6) is a newly classified autosomal-dominant cerebellar ataxia (ADCA) associated with CAG repeat expansion. We screened 111 patients with cerebellar ataxia for the SCA6 mutation. Of these, 35 patients were found to have expanded CAG repeats in the SCA6 gene, indicati...

Full description

Saved in:
Bibliographic Details
Published inNeurology Vol. 49; no. 5; p. 1238
Main Authors Matsumura, R, Futamura, N, Fujimoto, Y, Yanagimoto, S, Horikawa, H, Suzumura, A, Takayanagi, T
Format Journal Article
LanguageEnglish
Published United States 01.11.1997
Subjects
Adult
Age of Onset
Aged
Cloning, Molecular
Family Health
Genetic Testing
Homozygote
Humans
Infant
Japan
Magnetic Resonance Imaging
Male
Middle Aged
Spinocerebellar Degenerations - diagnosis
Spinocerebellar Degenerations - genetics
Trinucleotide Repeats
Japan
Online AccessGet more information

Cover

More Information
Summary:Spinocerebellar ataxia type 6 (SCA6) is a newly classified autosomal-dominant cerebellar ataxia (ADCA) associated with CAG repeat expansion. We screened 111 patients with cerebellar ataxia for the SCA6 mutation. Of these, 35 patients were found to have expanded CAG repeats in the SCA6 gene, indicating that second to SCA3, SCA6 is the most common ADCA in Japan. Expanded alleles ranged from 21 to 29 repeats, whereas normal alleles had seven to 17 repeats. There was no change in the CAG repeat length during meiosis. The age at onset was inversely correlated with the repeat length. The main clinical feature of the 35 patients with SCA6 was slowly progressive cerebellar ataxia; multisystem involvement was not common. The 35 patients included nine cases without apparent family history of cerebellar ataxia. The sporadic cases had smaller CAG repeats (21 or 22 repeats) and a later age at onset (64.9 +/- 4.9 years) than the other cases with established family history. We also identified one patient who was homozygous for the SCA6 repeat expansion. The homozygote showed an earlier age of onset and more severe clinical manifestations than her sister, a heterozygote carrying an expanded allele with the same repeat length as the homozygote. This finding suggests that the dosage of the CAG repeat expansion plays an important role in phenotypic expression in SCA6.
ISSN:0028-3878
DOI:10.1212/WNL.49.5.1238