Spacey Sian D, Materek Luke A, Szczygielski Blajez I, Bird Thomas D
Division of Neurology, Brain Research Center, University of British Columbia, Vancouver, Canada.
Arch Neurol. 2005 Feb;62(2):314-6. doi: 10.1001/archneur.62.2.314.
Episodic ataxia type 2 (EA2) is an autosomal dominant condition that results from mutations in the CACNA1A gene. It is characterized by episodes of ataxia and nystagmus that typically last hours.
To describe the clinical and genetic features of 2 unrelated patients who developed EA2 in childhood and late-onset dystonia.
Pedigree study.
University academic teaching hospital.
Two unrelated patients with childhood-onset EA2 and adult-onset dystonia were identified through a neurogenetics clinic. The CACNA1A gene was screened by heteroduplex analysis and sequencing for mutations.
Mutations in the CACNA1A gene.
Novel mutations in the pore-forming subunit of the P/Q-type calcium channels were found in both pedigrees. None of the family members carried an expansion of the CAG sequence that is found in the carboxy terminus of the CACNA1A gene.
Truncating mutations are the most common mutations to cause EA2. We have identified 2 novel truncating mutations that are associated with interictal dystonia. The dystonia is a late feature in this disease and may be a manifestation of a degenerative cerebellar process.
发作性共济失调2型（EA2）是一种常染色体显性遗传病，由CACNA1A基因突变引起。其特征为共济失调和眼球震颤发作，通常持续数小时。
描述2例儿童期发病的EA2及迟发性肌张力障碍的非亲缘关系患者的临床和遗传学特征。
系谱研究。
大学学术教学医院。
通过神经遗传学门诊确定了2例儿童期发病的EA2及成人期发病的肌张力障碍的非亲缘关系患者。采用异源双链分析和测序对CACNA1A基因进行突变筛查。
CACNA1A基因突变。
在两个家系中均发现了P/Q型钙通道孔形成亚基的新突变。所有家庭成员均未携带CACNA1A基因羧基末端存在的CAG序列扩增。
截短突变是导致EA2的最常见突变。我们发现了2种与发作间期肌张力障碍相关的新的截短突变。肌张力障碍是该病的晚期特征，可能是小脑退行性变的一种表现。
