Repeating exon 2 mutation caused by trans-splicing dystrophin gene in Duchenne muscular dystrophin (DMD) patient

ABSTRACT

The dystrophin gene is the largest human gene. Mutations in this gene cause Duchenne muscular dystrophin (DMD) disease. This is complex genomic unit exhibiting many errors splicing during mRNA process. More than 10 alternative splicing products have been identified in the 5' region of the dystrophin gene. In this study, two dystrophin transcripts including one containing exon 2 and exon X duplications, other one containing single exon 2 duplication were identified in peripheral blood lymphocytes of DMD case. Interestingly, genomic Southern blot analysis ruled out the hypothesis of duplication of dystrophin at exon 2. Therefore, these data suggested that exon 2 duplication transcripts were likely generated by trans-splicing event that occurring during the mARN maturation in which RNA segments of two independent transcripts are spliced together to generate a new mRNA species. However, the mechanisms modulating the trans-splicing activity of the dystrophin exon 2 remain to be clarified.