Patterns of dystrophin gene deletion in Egyptian Duchenne/Becker muscular dystrophy patients

Large variations in the proportion of intragenic deletion in the dystrophin gene have been observed in different populations. Although dystrophin gene deletion was extensively studied all over the world, only few studies were done on Egyptian population and there was no account on the dystrophin gene duplication. In this study, we present our results on the pattern of deletion of the dystrophin gene together with the usage of quantitative polymerase chain reaction (PCR) as a method for duplication analysis within the dystrophin gene in Egyptian patients. Forty one Duchene/Becker muscular dystrophy patients were included in this study. The diagnosis was based on detailed clinical assessment, serum creatine kinase (CK) level, neurophysiologic study and muscle biopsy for histopathological analysis. DNA was extracted from ten milliliter peripheral blood according to basic protocol, and multiplex polymerase chain reaction for dystrophin gene using both Chamberlin and Beggs sets of primers amplifying eighteen exons covering the two main dystrophin gene hot spots. In addition primers from Abbs set were used when it was necessary to check the exon borders. DNA from cases with no detectable deletion was analyzed for dystrophin gene duplication using quantitative PCR technique. We had a percentage of 61.1% deletion which is higher than data from previous Egyptian studies and most of the deletion was localized in the major hotspot region between exons 44 and 52 and we had 5% of the cases with duplication. Our results were compared with previous studies from Egypt and with studies from different populations especially with data recorded in the Middle East and North Africa.