ABSTRACT
Objective: To study the histopathological characteristics and mutation spectrum of patientspresenting with the Duchenne muscular dystrophy (DMD) phenotype. Methods: This wasa descriptive study conducted over a period of 8 years. Multiplex ligation-dependent probeamplification (MLPA) was done in patients presenting with the DMD phenotype. If MLPA wasnegative, patients were offered muscle biopsy for histopathological studies and/or nextgeneration sequencing (NGS) based multigene panel testing for muscular dystrophies.Results: Of the 510 patients included, mutation in the DMD gene was detected by MLPA in372 (72.9%), of whom 342 (67.1%) had exonic deletions and 30 (5.9%) had exonicduplications. Exons 45-55 were most commonly involved in large deletions and exons 1-10were the commonest exons involved in duplications. In the MLPA-negative cohort, 27proceeded for muscle biopsy. NGS was done in 14 patients, 10 of whom had pathogenicmutations in the DMD gene, 3 were non dystrophinopathies and no pathogenic variant couldbe identified in one patient. Conclusions: For patients presenting with the DMD phenotype,MLPA of the DMD gene has a high diagnostic rate of about 73%, and non-dystrophinopathies may constitute a small but significant proportion.