[Combining approach with multiplex PCR and MLPA to detect deletion and duplication in DMD patients, carriers, and prenatal diagnosis].

OBJECTIVE: Applying multiplex PCR and multiplex ligation-dependent probe amplification (MLPA) in a clinical setting to detect deletions and duplications in the Duchenne/Becker muscular dystrophy (DMD/BMD) gene not only for patients, but also for identification of possible carriers and prenatal diagnosis.

METHODS: Multiplex PCR was used first in patients clinically diagnosed with DMD/BMD to examine 26 exons for a large deletion in the two hot regions of the dystrophin gene. For patients without a deletion detected in the aforementioned regions, MLPA was used to further examine all 79 exons to determine whether a deletion in the remaining non-hot regions or any duplication was present. A similar approach was applied to suspected carriers. In requested prenatal diagnosis cases, specific PCR was used to detect deletions, while MLPA was applied to detect duplications.

RESULTS: Multiplex PCR was used to examine 26 exons within the two hot regions in the Dystrophin gene for 22 patients with DMD; 13 (13/22) had multi-exon deletions. For the 9 patients without deletions in the 26 exons, MLPA was used to examine 79 exons. 3 patients had duplications, 1 patient had a single deletion in exon 18, and no deletions or duplications could be detected in the remaining 5 patients. Of the 16 carriers, 2 out of the 3 that had family history had deletions, while the other 13 carriers were mothers of affected children who were sporadic patients without family history. Of them, 8 mothers were carriers for either deletions or duplications. For prenatal diagnosis, 9 fetuses were examined (one case was twins). Of them, 2 fetuses had familial deletions or duplications detected. These results were verified after induced abortion. In 7 fetuses, no deletions or duplications were detected and all developed into children.

CONCLUSION: Multiplex PCR can detect 92.86% of deletions and is useful for prenatal diagnosis of deletions because it is simple, reliable and inexpensive. It can be the first choice in DMD/BMD gene diagnosis. MLPA is important for detecting deletions in non-hot regions/exons and duplications in the DMD/BMD gene, as well as for carrier detection.