[Genetic analysis and prenatal diagnosis of Duchenne or Becker muscular dystrophy]

Objective: To explore the mutation characteristics of DMD gene in patients with Duchenne or Becker muscular dystrophy and female carriers, to provide effective prenatal diagnosis. Methods: Samples were collected from 94 male patients clinically diagnosed with Duchenne or Becker muscular dystrophy and 121 corresponding female relatives from Qingdao Women and Children's Hospital from June 2011 to October 2018. Multiplex ligation-dependent probe amplification (MLPA) was used to detect their DMD gene, and 23 high risk pregnants were performed prenatal diagnosis. Any candidate of DMD gene single-exon deletion was validated by further PCR amplification. The sample with whole DMD gene deletion was confirmed by chromosomal microarray analysis (CMA) to detect copy number variations and break site. Results: Among 94 clinical Duchenne or Becker muscular dystrophy patients, 66(70.2%, 66/94) were detected gene mutation; 56 cases were exon deletion mutation and 10 cases were duplication mutation. In 121 female relatives, 48 cases (39.7%, 48/121) were diagnosed as carriers. The mutation carrying rate, was 64.5% (40/62) identified in 62 mothers of Duchenne or Becker muscular dystrophy patients. Five Duchenne or Becker muscular dystrophy fetuses and 5 carrier fetuses were prenatally diagnosed in 23 high risk pregnants. Two children with the entire DMD gene deletion were identified more deletions at Xp21, with deletions of 6.66 Mb and 10.64 Mb respectively. Conclusions: MLPA may be an important method to detect DMD gene mutation of deletion and duplication. Therefore, the diagnosis of probands, female carriers and making an effective prenatal diagnosis are essential to reduce the birth of children with Duchenne or Becker muscular dystrophy.