DMD基因缺失及其在基因诊断中的应用

Studies on Gene Deletion in Duchenne Muscular Dystrophy and Its Application in Gene Diagnosis

应用DMD基因位点cDMD8探针和BglⅡ核酸内切酶对1例正常中国人及8例无亲缘关系的DMD患者的基因组DNA进行了分析。结果显示,正常中国人的杂交带型为11.0kb、7.4kb、3.5kb、2.6kb及1.0kb 5条杂交带,其中3.5kb为双杂交片段。8例病例中有4例可检测到基因缺失,缺失率为50％。缺失的部位、大小不同,呈现遗传异质性。本文讨论了cDNA探针在DMD基因诊断、携带者检出及产前基因诊断中的应用。

In the present study we analysed DNA from 9 boys, of whom 8 were unrelated DMD (Duchenne Muscular Dystrophy) patients, and 1 was a normal male. DNA samples were digested with Bgl Ⅱ and hybridized with a cDMDg probe from DMD gene. It was found that 5 hybridization band patterns of normal humans (11.0, 7.4, 3.5, 2.6 and 1.0 kb) were in close agreement with published reports in the literature. Of the 8 unrelated patients, 4 showed deletions of two or several exon-containing Bgl Ⅱ restriction fragments, and the deletion frequency was 50%. Deletions in DMD are heterogeneous both in size and position. The deletions are nonrandomly distributed. A 'hot spot' for deletions is near the center of the gene. Deletions in this region can be detected with a cDMD8 probe No correlation between apparent size and location of deletions and DMD phenotype was found. Deletion screening offers an advantage over the use of linked DNA probes. The presence of intragenic deletion in affected males permits more accurate prenatal diagnosis of pregnancies of fmeale relatives at the risk of being carriers of DMD.