BACKGROUND: The genetic diagnosis of Duchenne muscular dystrophy (DMD) has been complicated by the large size of the gene and its heterogeneous mutational spectrum. Multiplex PCR and multiplex ligation-dependent probe amplification (MLPA) are two well-established mutation screening methods. Here, we applied targeted next-generation sequencing (NGS) to clarify discrepant results between multiplex PCR and MLPA in a Chinese patient with DMD. METHODS: MLPA was performed to confirm multiplex PCR results obtained previously. Targeted NGS was then used to analyze the full-length DMD gene including introns. RESULTS: Multiplex PCR had previously identified an apparent deletion of exon 43 in the patient with DMD, but current MLPA indicated that exon 43 was present. Targeted NGS to clarify the genetic diagnosis identified a novel mutation, c.6241_c.6290 + 1109del1159insAC, which caused partial deletion of exon 43. This mutation removed the annealing sequence of the exon 43 reverse primer in multiplex PCR but had no influence on the hybridization site of the MLPA probe. Therefore, the discrepancy between the two methods was caused by partial exonic deletion that escaped MLPA detection. CONCLUSION: Targeted NGS disclosed a novel partial exonic deletion in the DMD gene as the cause of discrepancy between multiplex PCR and MLPA. Targeted NGS could be used to provide a more accurate genetic diagnosis of DMD, particularly in cases of partial exonic deletions, which will be of benefit in patient management and the identification of disease carriers.
BACKGROUND: The genetic diagnosis of Duchenne muscular dystrophy (DMD) has been complicated by the large size of the gene and its heterogeneous mutational spectrum. Multiplex PCR and multiplex ligation-dependent probe amplification (MLPA) are two well-established mutation screening methods. Here, we applied targeted next-generation sequencing (NGS) to clarify discrepant results between multiplex PCR and MLPA in a Chinese patient with DMD. METHODS: MLPA was performed to confirm multiplex PCR results obtained previously. Targeted NGS was then used to analyze the full-length DMD gene including introns. RESULTS: Multiplex PCR had previously identified an apparent deletion of exon 43 in the patient with DMD, but current MLPA indicated that exon 43 was present. Targeted NGS to clarify the genetic diagnosis identified a novel mutation, c.6241_c.6290 + 1109del1159insAC, which caused partial deletion of exon 43. This mutation removed the annealing sequence of the exon 43 reverse primer in multiplex PCR but had no influence on the hybridization site of the MLPA probe. Therefore, the discrepancy between the two methods was caused by partial exonic deletion that escaped MLPA detection. CONCLUSION: Targeted NGS disclosed a novel partial exonic deletion in the DMD gene as the cause of discrepancy between multiplex PCR and MLPA. Targeted NGS could be used to provide a more accurate genetic diagnosis of DMD, particularly in cases of partial exonic deletions, which will be of benefit in patient management and the identification of disease carriers.
Authors: Kevin M Flanigan; Diane M Dunn; Andrew von Niederhausern; Payam Soltanzadeh; Eduard Gappmaier; Michael T Howard; Jacinda B Sampson; Jerry R Mendell; Cheryl Wall; Wendy M King; Alan Pestronk; Julaine M Florence; Anne M Connolly; Katherine D Mathews; Carrie M Stephan; Karla S Laubenthal; Brenda L Wong; Paula J Morehart; Amy Meyer; Richard S Finkel; Carsten G Bonnemann; Livija Medne; John W Day; Joline C Dalton; Marcia K Margolis; Veronica J Hinton; Robert B Weiss Journal: Hum Mutat Date: 2009-12 Impact factor: 4.878