Chen Chen, Zhao Xuechao, Kong Xiangdong
Genetics and Prenatal Diagnosis Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450000, China.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2020 Dec 10;37(12):1364-1367. doi: 10.3760/cma.j.cn511374-20191225-00662.
To analyze the dynamic variant and clinical subtype of a pedigree affected with spinocerebellar ataxia (SCA) by using fluorescent-labeled primer combined with capillary electrophoresis.
Genomic DNA was extracted from 8 members including 6 patients and 2 healthy individuals from the pedigree. Six pairs of fluorescent-labeled primers were designed to screen pathological variants in association with common subtypes of SCA including SCA1, SCA2, SCA3, SCA6, SCA12 and SCA17.The PCR products were detected by capillary electrophoresis.
The number of CAG repeats in the SCA3 gene of the proband were determined as 8 and 70, exceeded the normal range(12 to 40), which suggested a diagnosis of SCA3. The other five patients were all detected with abnormal CAG repeats in the SCA3 gene, while the two healthy individuals were determined to be within the normal range.
The abnormal expansion of CAG repeats in the SCA3 gene probably underlay the pathogenesis of the disease in this pedigree. Combined fluorescent-labeled primers PCR and capillary electrophoresis can detect dynamic variants among SCA patients with efficiency and accuracy.
采用荧光标记引物结合毛细管电泳技术分析一个脊髓小脑共济失调（SCA）家系的动态变异及临床亚型。
从该家系的8名成员中提取基因组DNA，其中包括6例患者和2名健康个体。设计6对荧光标记引物，用于筛查与SCA常见亚型（包括SCA1、SCA2、SCA3、SCA6、SCA12和SCA17）相关的病理变异。通过毛细管电泳检测PCR产物。
先证者SCA3基因中的CAG重复序列数分别为8和70，超出正常范围（12至40），提示诊断为SCA3。其他5例患者的SCA3基因均检测到CAG重复序列异常，而2名健康个体的CAG重复序列在正常范围内。
SCA3基因中CAG重复序列的异常扩增可能是该家系疾病发病机制的基础。荧光标记引物PCR与毛细管电泳相结合可高效、准确地检测SCA患者中的动态变异。
