title: [Mitochondrial DNA A1555G mutation of seven families with nonsyndromic hearing loss].
abstract: OBJECTIVE
  To study mitochondrial DNA (mtDNA) A1555G mutation in seven families with nonsyndromic hearing loss (NSHL).
  
  
  METHODS
  Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and real time-amplification refractory mutation system-quantitative PCR (ARMS-qPCR) were applied to detect mtDNA A1555G mutation in seven NSHL families. Related clinical data were also collected and analyzed.
  
  
  RESULTS
  The mtDNA A1555G mutation was detected in members from the maternal side, including heteroplasmy and homozygosis, others were negative for this mutation. The copy number of homoplasmic or heteroplasmic mutations of mtDNA A1555G correlated well with the degree of deafness (R = 0.341, P = 0.022 and R = 0.85, P = 0.015, respectively).
  
  
  CONCLUSIONS
  The mutation rate of the mtDNA A1555G is high in the NSHL patients, the mutation type include heteroplasmy and homozygosis. There is significant correlation between the mtDNA A1555G copy number and the severity of hearing loss.
authors.affiliation: Department of Laboratory Medicine, First Affiliated Hospital, PR China. ouqishui@163.com
authors.forename: Qi-shui
authors.initials: QS
authors.lastname: Ou
authors.forename: Zu-jian
authors.initials: ZJ
authors.lastname: Cheng
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Lin
authors.initials: L
authors.lastname: Jiang
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D034381:Hearing Loss / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D017354:Point Mutation; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial