MOLECULAR DIAGNOSTICS OF DUCHENNE/BECKER MUSCULAR DYSTROPHY PATIENTS BY MULTIPLEX LIGATION-DEPENDENT PROBE AMPLIFICATION ANALYSIS AND DIRECT SEQUENCING

Duchenne/Becker muscular dystrophy (DMD/BMD), the most common X-linked muscular dystrophy is caused by mutations in the enormously large DMD gene. We screened this gene in 51 unrelated Bulgarian DMD/BMD patients and four families with no living index patient available, by multiplex ligation-dependent probe amplification (MLPA) analysis, which is a powerful tool for detecting deletion/duplication along the DMD gene. This, in combination with direct sequencing, characterized the mutation in all patients, which comprised 42 deletions (82%), six duplications (12%) and three point mutations (6%), and precisely determined all deletion/duplication borders. In all the families with no living index patient available, deletions were detected by direct analysis on the patients' mothers and sisters, proving the value of MLPA for carrier status determination.