title: Similarity of DMD gene deletion and duplication in the Chinese patients compared to global populations.
abstract: BACKGROUND
  DNA deletion and duplication were determined as the major mutation underlying Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD).
  
  
  METHODS
  Applying multiplex ligation-dependent probe amplification (MLPA), we have analyzed 179 unrelated DMD/BMD subjects from northern China.
  
  
  RESULTS
  Seventy-three percent of the subjects were found having a deletion (66.25%) or duplication (6.25%). Exons 51-52 were detected as the most common fragment deleted in single-exon deletion, and the region of exons 45-50 was the most common exons deleted in multi-exon deletions. About 90% of DMD/BMD cases carry a small size deletion that involves 10 exons or less, 26.67% of which carry a single-exon deletion. Most of the smaller deletions resulted in an out-of-frame mutation. The most common exons deleted were determined to be between exon 48 and exon 52, with exon 50 was the model allele. Verifying single-exon deletion, one sample with a deletion of exon 53 that was initially observed from MLPA showed that there was a single base deletion that abolished the ligation site in MLPA. Confirmation of single-exon deletion is recommended to exclude single base deletion or mutation at the MLPA ligation site.
  
  
  CONCLUSIONS
  The frequency of deletion and duplication in northern China is similar to global ethnic populations.
authors.affiliation: Peking University Center of Medical Genetics, Peking University, Beijing, China. hangzhihuang_pumc@yahoo.com.cn.
authors.forename: Xiaozhu
authors.initials: X
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.forename: Shangzhi
authors.initials: S
authors.lastname: Huang
authors.forename: Tian-Jian
authors.initials: TJ
authors.lastname: Chen
authors.forename: Nanbert
authors.initials: N
authors.lastname: Zhong