J Korean Med Sci.  1999 Dec;14(6):659-664. 10.3346/jkms.1999.14.6.659.

Spinocerebellar ataxia type 2 in seven Korean families: CAG trinucleotide expansion and clinical characteristics

• Kim JM
• Shin SS
• Kim JY
• Joo SI
• Park SS
• Kim JW
• Jeon BS

• KMID: 646043
• DOI: http://doi.org/10.3346/jkms.1999.14.6.659

Abstract

Studies on spinocerebellar ataxias (SCA) have been hampered by a lack of disease markers. Clinical and pathological heterogeneity also made the classification unreliable. Linkage studies established that there are multiple subtypes of SCA. Five types are found to have unstable CAG expansion; the diagnosis can be established by molecular genetic study. Therefore, we systemically screened degenerative ataxia patients for these five SCA types, and identified eight patients with SCA2 (seven from six families and one sporadic case). This paper presents the clinical information on the seven patients, whose clinical information was available in detail. CAG repeat expansion in the patients ranged from 38 to 47 (normal control, 19 to 27). The onset ages ranged from 16 to 41 with 27.1 years as the mean, which correlated inversely with repeat lengths. All patients presented dysarthria and gait ataxia. Upper limb dysmetria or dysdiadochokinesia appeared later but progressed, causing severe disability. Slow saccade (4 patients in 7) and decreased DTR (4 in 7) were common. MRIs showed severe atrophy of the brainstem and cerebellum in all patients. We conclude that SCA2 is the most frequent type in Korea and carries rather pure cerebellar syndrome, slow saccade, and hyporeflexia.

Keyword

Spinocerebellar degeneration; Cerebellar ataxia; Cerebellar angiography

MeSH Terms

Adolescence
Adult
Age of Onset
Brain/pathology
DNA Mutational Analysis
Female
Human
Korea
Lymphocytes
Magnetic Resonance Imaging
Male
Spinocerebellar Ataxias/genetics*
Spinocerebellar Ataxias/diagnosis
Spinocerebellar Ataxias/blood
Trinucleotide Repeats/genetics*