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

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.

Clinical analysis of huntington's disease in Korea

Huntington's disease(HD) is clinically diagnosed by the triad of autosomal dominant inheritance, involuntary movements mainly chorea, and dementia. The phenotype of HD is variable and other diseases can have the same phenocopy. A definite diagnosis of Huntington's disease cannot be made by clinical informations alone Pathologic or genetic studies was necessary to exclude other neurodegenerative diseases which may present with familial dementia or chorea. Therefore, genetic studies of HD become essential for confirmatory diagnosis. Recent discovery of an expanded CAG trinucleotide repeat at the telomeric position of chromosome 4p made the diagnosis possible even in sporadic and presymptomatic cases. We previously demonstrated expantion of CAG repeats in clinically diagnosed HD, and were able to find presymptomatic. We herein present the clinical and genetic information in all the cases of genetically confirmed HD. 1) There was a clear gap between the number of CAG repeats in HD and normal and disease control. 2) Two out of three patients who had chorea without family history were confirmed as HD by genetic study. 3) One who had psychosis and a family history of HD was shown not to be HD. 4) We found 12 asymptomatic cases with HD mutation during family screening. 5) Caudate atrophy in MRI was not seen in the early stage of HD. Our data confirms that gene analysis is a powerful tool to make a diagnosis of HD even in sporadic and presymptomatic cases. Proper genetic counselling after judicious preparation of the family and society is sorely needed.

Clinical analysis of huntington's disease in Korea

Huntington's disease(HD) is clinically diagnosed by the triad of autosomal dominant inheritance, involuntary movements mainly chorea, and dementia. The phenotype of HD is variable and other diseases can have the same phenocopy. A definite diagnosis of Huntington's disease cannot be made by clinical informations alone Pathologic or genetic studies was necessary to exclude other neurodegenerative diseases which may present with familial dementia or chorea. Therefore, genetic studies of HD become essential for confirmatory diagnosis. Recent discovery of an expanded CAG trinucleotide repeat at the telomeric position of chromosome 4p made the diagnosis possible even in sporadic and presymptomatic cases. We previously demonstrated expantion of CAG repeats in clinically diagnosed HD, and were able to find presymptomatic. We herein present the clinical and genetic information in all the cases of genetically confirmed HD. 1) There was a clear gap between the number of CAG repeats in HD and normal and disease control. 2) Two out of three patients who had chorea without family history were confirmed as HD by genetic study. 3) One who had psychosis and a family history of HD was shown not to be HD. 4) We found 12 asymptomatic cases with HD mutation during family screening. 5) Caudate atrophy in MRI was not seen in the early stage of HD. Our data confirms that gene analysis is a powerful tool to make a diagnosis of HD even in sporadic and presymptomatic cases. Proper genetic counselling after judicious preparation of the family and society is sorely needed.