The spectrum of deletions and duplications in the dystrophin (DMD) gene in a cohort of patients with Duchenne muscular dystrophy in Sri Lanka

Background: Duchenne muscular dystrophy (DMD), which affects 1 in 3500 newborn males, is the most common fatal neurodegenerative disorder in children. Deletions and duplications in the DMD gene are the most common underlying etiological factors. Materials and Methods: Fifty consecutive children with DMD were screened for deletions and duplications in the DMD gene using Multiple Ligation-binding Probe Amplification (MLPA). Results: Forty (80%) children had deletions and 4 (8%) had duplications. Single exon involvement was seen in 8 (16%), two exon involvement was seen in 3 (6%), three exon involvement was seen in 6 (12%) children, and four exon involvement in 1 (2%) child. More than four exon involvement were seen in 26 (52%) children. The most common deletion was the deletion spanning from exon 45 to exon 52, which was seen in 6 (12%) children. The next common exon deletion was single exon 45 deletion seen in 4 (8%) children. The most frequent mutant region fell within exons 45 to 55 (52%) followed by within exons 21 to 44 (26%) and exons 1 to 20 (26%). The least common region fell within exons 56 to 79 (4%). Conclusion: The deletion/duplication pattern seen in this cohort of children with DMD was similar to that reported among other global populations.