title: A family with mild clinical manifestations of spinocerebellar ataxia type 1 (SCA1): correlation with smaller CAG repeats.
abstract: Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat. We analyzed CAG repeat expansion in one Japanese SCA1 family with mild clinical manifestations. Clinically, this SCA1 family showed less frequent nystagmus (p = 0.045, Fisher's exact-test) in comparison with duration-matched control patients with larger numbers of CAG repeats (48.4 ± 4.2, p < 0.01). Some patients showed no other signs than cerebellar ataxia in the earlier stage. All six patients had expanded alleles for SCA1 with relatively small CAG repeats (41.5 ± 1.0, mean ± SD), which may be related to the mild clinical symptoms of the disease. The present results also suggest that slow saccades and amyotrophy are constantly observed in 30-40% of SCA1 patients without regard to the size of CAG repeats, while the frequency of nystagmus decreases with reduction in size of the CAG expansion.
authors.affiliation: Department of Neurology, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-77, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kameya
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: M
authors.initials: M
authors.lastname: Aoki
authors.forename: Y
authors.initials: Y
authors.lastname: Itoyama