Institute of Human Genetics, University of Lübeck, Lübeck, Germany.
Cerebellum. 2007;6(4):300-7. doi: 10.1080/14734220601136177. Epub 2007 Jan 19.
The spinocerebellar ataxia type 17 (SCA17) is characterized by cerebellar ataxia, dementia, and involuntary movements, including chorea and dystonia. In addition, psychiatric symptoms, pyramidal signs, and rigidity are common. MRI shows variable atrophy of the cerebrum, brainstem, and cerebellum. The autosomal dominantly inherited progressive neurodegenerative disorder is caused by an expanded CAA/CAG repeat coding for glutamine. Alleles of the normal range carry 25 to 42 glutamine residues, disease causing alleles 43 to 63. Alleles with 43 to 48 glutamine codons may be associated with incomplete penetrance. The mean age of onset is about 30 years for individuals with full-penetrance alleles, but ranges from three to 55 years.
脊髓小脑共济失调 17 型（SCA17）的特征是小脑共济失调、痴呆和不自主运动，包括舞蹈病和肌张力障碍。此外，常见的还有精神症状、锥体束征和僵硬。MRI 显示大脑、脑干和小脑的体积可变萎缩。这种常染色体显性遗传性进行性神经退行性疾病是由编码谷氨酰胺的 CAA/CAG 重复扩展引起的。正常范围的等位基因携带 25 到 42 个谷氨酰胺残基，致病等位基因携带 43 到 63 个。携带 43 到 48 个谷氨酰胺密码子的等位基因可能与不完全外显相关。完全外显的等位基因个体的平均发病年龄约为 30 岁，但发病年龄范围为 3 到 55 岁。
