Frequency of spinocerebellar ataxia types 1, 2, 3, 6, 7 and dentatorubral pallidoluysian atrophy mutations in Korean patients with spinocerebellar ataxia

Autosomal dominant cerebellar ataxias (ADCAs) are a heterogeneous group of disorders characterized by degenerative symptoms in the cerebellum, spinal cord, and brain stem. Six different genes have been reported to be associat ed with ADCA, and the length of trinucleotide repeats of these genes is cor related with the age at onset and severity of symptoms. Although there are strong hereditary effects in these disorders, most of the studies carried o ut in heterogeneous populations and in small groups obscure the true incide nce of these diseases. We examined the frequency of six types of ADCAs in 8 7 unrelated Korean patients with progressive ataxia and compared the result s to the frequencies in other ethnic groups. Spinocerebellar ataxia (SCA) t ype 2 was the most frequent hereditary ataxia (12.6%) and types 3 and 6 acc ounted for 4.6% and 6.9% of ataxia patients, respectively. Dentatorubral pa llidoluysian atrophy was also found in three patients (3.4%). No instances of SCA types 1 or 7 were detected. These findings show the striking contras t to the white population and a difference from Japanese findings. Our resu lts demonstrate that dentatorubral pallidoluysian atrophy should be include d in the differential diagnosis of Korean patients with spinocerebellar ata xia, and that there are strong hereditary effects in patients with ADCAs.