title: Investigation of molecular diagnosis in Chinese patients with myotonic dystrophy type 1.
abstract: BACKGROUND
  Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystem disease caused by abnormal expansion of cytosine-thymine-guanine (CTG) repeats in the myotonic dystrophy protein kinase gene. The clinical manifestations of DM1 are multisystemic and highly variable, and the unstable nature of CTG expansion causes wide genotypic and phenotypic presentations, which make molecular methods essential for the diagnosis. So far, very few studies about molecular diagnosis in Chinese patients with DM1 have been reported. Therefore, we carried out a study using two different methods in molecular diagnosis to verify the validity in detecting CTG expansion in Chinese patients showing DM signs.
  
  
  METHODS
  A total of 97 Chinese individuals were referred for molecular diagnosis of DM1 using conventional polymerase chain reaction (PCR) accompanied by Southern blotting and triplet primed PCR (TP-PCR). We evaluated the sensitivity and limitation of each method using percentage.
  
  
  RESULTS
  By conventional PCR 65 samples showed only one fragment corresponding to the normal allele and 62 out of them were correctly diagnosed as DM1 by TP-PCR and three homologous non-DM1 samples were ruled out; Southern blotting analysis successfully made 13 out of 16 correct diagnoses with a more sensitivity using α-(32)P-labeled probes than dig-labeled probes.
  
  
  CONCLUSIONS
  Molecular analysis is necessary for the diagnosis of DM1 and TP-PCR is a reliable, sensitive, and easily performed method in molecular diagnosis which is worthy to be popularized.
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Mao
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Zhanjun
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Cui
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ling
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Chuanqiang
authors.initials: C
authors.lastname: Pu
authors.affiliation: Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China. Email: lewish301@sina.com.
authors.forename: Xusheng
authors.initials: X
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D015139:Blotting, Southern; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009223:Myotonic Dystrophy / Q000175:diagnosis* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D055815:Young Adult