title: Optimization PCR for Detection CTG/CCTG-Repeat Expansions in the Diagnosis of Myotonic Dystrophies.
abstract: BACKGROUND
  Myotonic dystrophies (DMs) are a group of autosomal dominant neuromuscular disorders which are caused by large CTG/CCTG-repeat expansions in untranslated regions of DMPK/ZNF9 gene. The "phenotypic overlap" in DMs creates complication in distinguishing patients with DM1 from patients with DM2 and underscores the need for these patients to undergo genetic test; therefore, detection and accurate sizing of the CTG/CCTG-repeat expansions are necessary. Templates with long CTG/CCTG tandem repeats are difficult to amplify by convention PCR.
  
  
  OBJECTIVE
  The aim of our study was to develop an efficient, economic amplification method which based on combination of primer design, modified annealing, and extension conditions in PCR amplification.
  
  
  METHODS
  We detected and analyzed the CTG-repeat expansions in patients having clinical, electrophysiological, and muscle pathology features indicative of DMs by optimization PCR. If no CTG-repeat expansions were detected, we subsequently analyzed the CCTG-repeat expansions in the remaining patients.
  
  
  RESULTS
  42 participants included 25 DMs patients and 17 family members. 22 patients showed CTG-repeat expansions, the CTG-repeat ranged from 53 to 683 and the average was 535; 3 patients showed CCTG-repeat expansions, the CCTG-repeat ranged from 400 to 450 and the average was 416.
  
  
  CONCLUSIONS
  Molecular genetic tests are essential for DMs diagnosis; Optimization PCR under the optimal conditions of primer design, modified annealing, and extension conditions can be used for efficient PCR in DMs diagnosis; Optimization PCR can greatly improve the positive detection of DMs, provide an economic, accurate, and rapid method for routine diagnostic use.
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Yan-Xin
authors.initials: YX
authors.lastname: Meng
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Hong-Rui
authors.initials: HR
authors.lastname: Shen
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Bing
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, China Jinghu5510@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D017931:DNA Primers; D042622:DNA Repeat Expansion / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D009223:Myotonic Dystrophy / Q000175:diagnosis* / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods*; D016601:RNA-Binding Proteins / Q000235:genetics; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
chemical_list: C433227:CNBP protein, human; D017931:DNA Primers; D016601:RNA-Binding Proteins
keywords: CTG/CCTG; GC-rich; Myotonia dystrophies; PCR analysis