Department of Laboratory Medicine, West China Hospital of Sichuan University, Sichuan Province, No. 37 Guoxue Lane, Chengdu, 610041, People's Republic of China.
Department of Neurology, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
Neurol Sci. 2022 Feb;43(2):1435-1439. doi: 10.1007/s10072-021-05769-z. Epub 2022 Jan 7.
An elderly Chinese male patient was diagnosed with compound heterozygous spinocerebellar ataxia type 8; molecular diagnosis found that the (CTA)n(CTG)n repeat unit of his ATXN8/ATXN8OS gene was 134/93. The patient has a 6-year medical history, mainly manifested by ataxia, dysarthria, abnormal eye movements, and pyramidal signs. Magnetic resonance imaging (MRI) showed no obvious abnormalities in the medulla oblongata and cervical spinal cord except for cerebellar atrophy and sulci enlargement. There are heterozygous SCA8 individuals among his family members, but there are significant differences in their onset age and clinical manifestations.
This case reminds us that (CTA)n(CTG)n repeats are very prone to dynamic mutations in intergenerational inheritance, and the ATXN8/ATXN8OS gene penetrance is different in different SCA8 individuals, which suggests that genetic detection is of great importance.
一名老年华裔男性患者被诊断为脊髓小脑共济失调 8 型复合杂合子；分子诊断发现其 ATXN8/ATXN8OS 基因的（CTA）n（CTG）n 重复单位为 134/93。该患者有 6 年病史，主要表现为共济失调、构音障碍、眼球运动异常和锥体束征。磁共振成像（MRI）除小脑萎缩和脑沟增宽外，延髓和颈髓未见明显异常。其家族中有杂合子 SCA8 个体，但发病年龄和临床表现存在明显差异。
本例提醒我们，（CTA）n（CTG）n 重复在代际遗传中极易发生动态突变，不同 SCA8 个体的 ATXN8/ATXN8OS 基因外显率不同，这表明基因检测非常重要。
