Evaluation of Dystrophin Gene Deletion Patterns in a Large Duchene/Becker Msuscular Dystrophy Patient Sample; 17 Years Experience from one Turkish Diagnostic Center

Background: Duchenne/Becker muscular dystrophy (DMD/BMD) is an X-linked recessive disease results from mutations in the dystrophin gene. We established the deletion pattern profile in unrelated DMD/BMD patients using multiplex PCR (M-PCR). Methods: During 1998-2015, 1,385 unrelated Deletion analysis in the dystrophin(DMD) gene was performed.Results: Of all patients admitted, 42.6% deletion carriers (n=589) were detected, of which 180 (80.3 %)were carrying single exon deletions and 409 (14.8 %) multiple exon deletions. Deletions covering the major hotspot region were 80.3 %, the minor region 14.8% and 2.4% covered both regions. The mean age of diagnosis of patients with out-of-frame deletions (7.27 year) was notably lower than the cases with in frame deletions (17.54 year). No single exon 4 deletion was detected.Conclusions: When the known deletion hotspots are considered, the study population showed a similar deletion pattern with other populations. The mean age of patients with out-of-frame deletions were lower than mean age of those with in-frame deletions, in concordance with the reading frame hypothesis. Strikingly, no single exon 4 deletion was found, supporting the hypothesis that absence of it might have no functional consequences