BglⅡ-BlnⅠ剂量检测方法在面肩肱型肌营养不良症1A基因诊断中的应用

目的 通过检测染色体4q35和10q26之间的易位情况，进一步提高面肩肱型肌营养不良症1A(hcioscapulohumeral muscular dystrophy，FSHD1A)基因诊断的准确性。方法 应用Bgl Ⅱ-Bln Ⅰ剂量检测方法，对7例基因诊断阳性的FSHD症状前患者和5例基因诊断阴性而临床诊断为散发性FSHD患者的染色体4q35和10q26的易位状况进行分析。用Bgl Ⅱ和Bin Ⅰ酶切基因组DNA后行琼脂糖凝胶电泳，制备p13E-11探针并以α^-32P dCTP标记，进行Southern杂交及放射自显影。应用图像分析系统和薄层扫描仪对4q与10q杂交片段的信号强度进行定量分析，判断4q35和10q26的易位情况。结果 在基因诊断阳性的7例FSHD症状前患者中，1例发生了4q35至10q26的易位，有可能为假阳性基因诊断。在基因诊断阴性的5例散发性FSHD患者中，1例发生了10q26至4q35的易位，可能为假阴性基因诊断。其余10例未发现4q35和10q26之间的易位．结论 应用Bgl Ⅱ-Bln Ⅰ剂量检测方法，可以检出染色体4q35和10q26之间的易位，能够进一步提高FSHD1A基因诊断的准确性。

Application of the BglⅡ-BlnⅠ dosage test to gene diagnosis of facioscapulohumeral muscular dystrophy 1A gene

OBJECTIVE: To increase the sensitivity and specificity of conventional gene diagnosis of facioscapulohumeral muscular dystrophy 1A(FSHD1A) by analyzing the distribution of translocation between chromosomes 4q35 and 10q26 in suspected FSHD cases. METHODS: The Bgl II- Bln I dosage test was performed to detect translocation between chromosomes 4q35 and 10q26 in 7 cases of presymptomatic FSHD patients showing positive result in gene diagnosis and 5 cases of sporadic FSHD patients showing negative result in gene diagnosis. DNA samples were digested with Bgl II and Bln I, followed by agrose gel electrophoresis. Probe p13E-11 was labeled with alpha-(32) P dCTP, followed by Southern hybridization. Then the ratio between the chromosomes 4 and 10 derived signal intensities was judged and hence was made known whether there was interchromosomal translocation between chromosomes 4 and 10. RESULTS: The Bgl II-Bln I dosage test revealed a translocation from chromosome 4q35 to 10q26 in one presymptomatic FSHD patient, thus indicating the result of gene diagnosis for her might be false positive. There was one translocation from chromosome 10q26 to 4q35 detected in one sporadic FSHD patient, indicating the result of gene diagnosis for her might be false negative. There were no translocations between chromosomes 4 and 10 in the other 10 cases. CONCLUSION: The Bgl II-Bln I dosage test can detect the translocation between chromosomes 4q35 and 10q26. It can improve the accuracy of the conventional method for gene diagnosis of FSHD1A.