Vuillaume I, Schraen S, Rousseaux J, Sablonnière B
Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital R. Salengro, Lille, France.
Diagn Mol Pathol. 1998 Jun;7(3):174-9. doi: 10.1097/00019606-199806000-00009.
To date, eight neurodegenerative diseases, including Huntington's disease, dentatorubral-pallidoluysian atrophy, spinal and bulbar muscular atrophy, and spinocerebellar ataxia (SCA) types 1, 2, 3, 6, and 7, have been proven to be caused by an expanded trinucleotide repeat (CAG)n located within a specific gene for each of these diseases. Except in SCA 6, the CAG repeat is present in approximately 7 to 35 copies in the normal population, whereas patients have CAG expansions of 40 to approximately 75 repeats. Sizing of the repeat length enables molecular diagnosis in affected patients and presymptomatic persons carrying a mutated allele. A molecular protocol for the diagnosis of these diseases was developed based on polymerase chain reaction, denaturing polyacrylamide gel electrophoresis and staining with silver nitrate, and adapted to each disease. This simple and rapid method gives a sensitivity of detection equal to current procedures but avoids isotopic manipulations. Therefore, shorter turnaround time, decreased cost per sample, and simplified screening of these neurodegenerative diseases by PCR-based assays may be attainable using this protocol.
迄今为止，包括亨廷顿舞蹈病、齿状核红核苍白球路易体萎缩症、脊髓延髓肌萎缩症以及1型、2型、3型、6型和7型脊髓小脑共济失调症在内的8种神经退行性疾病已被证实是由位于这些疾病各自特定基因内的三核苷酸重复序列（CAG）n扩增所致。除脊髓小脑共济失调症6型外，正常人群中CAG重复序列约有7至35个拷贝，而患者的CAG重复序列扩增至40至约75个拷贝。重复序列长度的测定有助于对患病个体以及携带突变等位基因的无症状者进行分子诊断。基于聚合酶链反应、变性聚丙烯酰胺凝胶电泳以及硝酸银染色开发了一套针对这些疾病的分子诊断方案，并针对每种疾病进行了调整。这种简单快速的方法检测灵敏度与现有方法相当，但避免了同位素操作。因此，使用该方案通过基于聚合酶链反应的检测方法，可能实现更短的周转时间、降低每个样本的成本以及简化这些神经退行性疾病的筛查。
