Analysis of Dystrophin Gene Deletions by Multiplex PCR in Moroccan Patients

Duchenne and Becker muscular dystrophy (DMD and BMD) are X-linked diseases resulting from a defect in the dystrophin gene located on Xp21. DMD is the most frequent neuromuscular disease in humans (1/3500 male newborn). Deletions in the dystrophin gene represent 65% of mutations in DMD/BMD patients. We have analyzed DNA from 72 Moroccan patients with DMD/BMD using the multiplex polymerase chain reaction (PCR) to screen for exon deletions within the dystrophin gene, and to estimate the frequency of these abnormalities. We found dystrophin gene deletions in 37 cases. Therefore the frequency in Moroccan DMD/BMD patients is about 51.3%. All deletions were clustered in the two known hot-spots regions, and in 81% of cases deletions were detected in the region from exon 43 to exon 52. These findings are comparable to those reported in other studies. It is important to note that in our population, we can first search for deletions of DMD gene in the most frequently deleted exons determined by this study. This may facilitate the molecular diagnosis of DMD and BMD in our country

A maternally derived complex small supernumerary marker chromosome involving chromosomes 8 and 14: case report and review of the literature

Introduction: The majority of small supernumerary marker chromosomes (sSMCs) are derived from one single chromosome. Complex sSMCs, on the other hand, consist of genetic material derived from more than one, normally two chromosomes. Complex sSMCs involving chromosomes 8 and 14 are rarely encountered.Case presentation: We present here a 14-month-old boy born from an unrelated couple. At birth, the baby was hypotonic and had a cleft lip and palate, as well as ocular involvement. Throughout the course of development, the baby experienced feeding difficulties, stunted growth, and delayed psychomotor development. Banding together with molecular cytogenetics revealed a balanced maternal translocation t(8;14)(p22.3;q21)mat, leading due to meiotic 3:1 segregation to a partial trisomy of chromosomes 8 and 14 in the affected boy.Discussion/Conclusion: This report highlights the importance of cytogenetics in diagnosis of rare genetic disorders, with impact on genetic counselling of patients and their families. There are three comparable cases in the literature involving both chromosomes 8 and 14, but with different breakpoints; the complex sSMC derived from chromosomes 8 and 14 in this case, characterized as der(14)t(8;14) (p22.3;q21)mat