engleski

Improved detection of deletions/duplications in the DMD gene using the multiplex-ligation-dependent probe amplification (MLPA) method

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), the most common forms of dystrophinopathies, are X-linked disorders caused by mutations of the DMD gene. DMD gene spans 2.4 Mb on Xp21 and contains 79 exons. Until recently, the majority of the DMD deletions have been traditionally identified in affected males by using a multiplex polymerase chain reaction (PCR) approach that simultaneously amplifies ~19 exons. However, by that approach duplications and female carriers could not be identified with certainty. Here we report the use of Multiplex Ligation-dependent Probe Amplification (MLPA) assay in simultaneously screening of all 79 DMD exons for deletions and duplications in DMD/BMD patients and female carriers. We validated the MLPA assay by testing 19 unrelated male patients already screened by multiplex PCR. The MLPA results were in concordance with the results of multiplex PCR in 9 cases. In six DMD/BMD patients we could more precisely determine the extent of the deletions which could be of prognostic value for the patients. There were differences in the deletion breakpoints determined by the two methods in two patients, probably due to point mutation or small insertion/deletion in the MLPA probe hybridization site. In addition, we detected two duplications that had been missed by multiplex PCR. The assay reliably identified 4 female heterozygotes. The MLPA assay outperforms the Beggs and Chamberlain multiplex PCR test and should be the method of choice for the detection of DMD rearrangements in DMD/BMD patients, as well as in female carriers.

DMD

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