Duchenne muscular dystrophy: High-resolution melting curve analysis as an affordable diagnostic mutation scanning tool in a South African cohort
Background. Duchenne/Becker muscular dystrophy (D/BMD) is an X-linked recessive muscle disorder affecting 1/3 500 live male births worldwide. Up to 70% of all D/BMD cases are caused by exonic deletions or duplications routinely identified in diagnostic laboratories worldwide. The remaining patients harbour other sequence alterations for which testing availability is limited owing to the expense of interrogating the large DMD gene. Genetic screening for D/BMD in South Africa currently includes multiple ligase-dependent probe amplification (MLPA) for exonic deletions and duplications and linkage analysis. No genetic testing for small mutations in the DMD gene is offered, leaving a third of D/BMD families without genetic closure. The advent of potential mutation-specific therapies for DMD necessitates comprehensive testing protocols.
Objective. To investigate the effectiveness and affordability of high-resolution melting curve analysis (hrMCA) for detection of small/point mutations in the DMD gene, for possible inclusion into the local public health-funded diagnostic service.
Methods. DNA from 24 patients who had previously tested deletion-negative with multiplex polymerase chain reaction (mPCR) was analysed by MLPA and hrMCA.
Results. MLPA revealed eight previously undetected exonic rearrangements: five deletions and three duplications. HrMCA of the remaining samples revealed three nonsense, four frameshifts, one splice-site, one missense and one single-base substitution in the Dp427promoter/ exon1 of the DMD gene. In addition, 41 polymorphisms and three changes of uncertain significance were detected.
Conclusion. These findings identify hrMCA as an affordable and effective mutation scanning tool for incorporation into the local diagnostic setting, allowing for better genetic counselling of more DMD families and selection of potential candidates for future therapies.
Copyright remains in the Author’s name. The work is licensed under a Creative Commons Attribution - Noncommercial Works License. Authors are required to complete and sign an Author Agreement form that outlines Author and Publisher rights and terms of publication. The Agreement form should be uploaded along with other submissions files and any submission will be considered incomplete without it [forthcoming].
Material submitted for publication in the SAMJ is accepted provided it has not been published or submitted for publication elsewhere. Please inform the editorial team if the main findings of your paper have been presented at a conference and published in abstract form, to avoid copyright infringement. The SAMJ does not hold itself responsible for statements made by the authors.
Previously published images
If an image/figure has been previously published, permission to reproduce or alter it must be obtained by the authors from the original publisher and the figure legend must give full credit to the original source. This credit should be accompanied by a letter indicating that permission to reproduce the image has been granted to the author/s. This letter should be uploaded as a supplementary file during submission.