Storey E, Forrest S M, Shaw J H, Mitchell P, Gardner R J
Department of Neuroscience, Monash University, Prahran, Australia.
Arch Neurol. 1999 Jan;56(1):43-50. doi: 10.1001/archneur.56.1.43.
Spinocerebellar ataxia type 2 (SCA2) is a recently delineated cause of autosomal dominant cerebellar ataxia type I. The basic clinical neurologic features of SCA2 have been described in the literature, but neuropsychological features have not, despite statements that some patients became demented.
To describe the clinical and neuropsychological features of patients from a pedigree with SCA2.
We studied 8 affected members of an Australian pedigree of northern Italian origin with autosomal dominant cerebellar ataxia type I caused by SCA2. Patients underwent clinical neurologic examination and abbreviated neuropsychological testing, while some also underwent magnetic resonance imaging. The results were compared with pooled results from previously published studies of patients with SCA2.
The pedigree displayed anticipation, with earlier onset in later generations, and there was an inverse correlation between repeat number and age at onset. The principal difference from other clinical reports of SCA2 was our finding of unequivocal frontal-executive dysfunction in 5 of 6 individuals who could be tested quantitatively, despite Mini-Mental State Examination scores in the nondemented range. This feature did not appear to correlate with either repeat size or duration of illness.
In light of a recent report of frontal-executive dysfunction in spinocerebellar ataxia type III, we postulate that this pattern may be common to the autosomal dominant cerebellar ataxias and frequently may be overlooked because of the insensitivity of routine screening tests such as the Mini-Mental State Examination.
2型脊髓小脑共济失调（SCA2）是最近确定的常染色体显性遗传性I型小脑共济失调的病因。SCA2的基本临床神经学特征已有文献报道，但神经心理学特征尚未见报道，尽管有说法称部分患者会出现痴呆。
描述一个SCA2家系患者的临床和神经心理学特征。
我们研究了一个起源于意大利北部的澳大利亚家系中的8名受影响成员，他们患有由SCA2引起的常染色体显性遗传性I型小脑共济失调。患者接受了临床神经学检查和简化的神经心理学测试，部分患者还接受了磁共振成像检查。将结果与先前发表的SCA2患者研究汇总结果进行比较。
该家系显示出遗传早现现象，后代发病年龄更早，且重复序列数量与发病年龄呈负相关。与其他SCA2临床报告的主要差异在于，在6名能够进行定量测试的个体中，我们发现有5人存在明确的额叶执行功能障碍，尽管简易精神状态检查得分处于非痴呆范围。这一特征似乎与重复序列大小或病程均无关联。
鉴于最近有关于III型脊髓小脑共济失调额叶执行功能障碍的报道，我们推测这种模式可能是常染色体显性遗传性小脑共济失调的共同特征，且由于简易精神状态检查等常规筛查测试不够敏感，可能经常被忽视。
