title: Balanced and unbalanced reciprocal translocation: an overview of a 30-year experience in a single tertiary medical center in Taiwan.
abstract: BACKGROUND
  Reciprocal translocation is the most common type of translocation; however, there are only a few studies that address the indications for reciprocal translocation in amniocentesis. Here we share our data, based on 30 years' experience in a single tertiary center, to investigate the rates and indications for amniocentesis in cases of reciprocal translocations.
  
  
  METHODS
  A retrospective review of 16,749 pregnant women, who underwent midtrimester amniocentesis between January 1981 and December 2010, was conducted. Seventy-four cases of reciprocal translocation were identified.
  
  
  RESULTS
  The percentage of reciprocal translocations in all amniocentesis cases was 0.44% (74/16,749); of these 74 cases, 56 were balanced and 18 unbalanced. De novo abnormality occurred in 23 cases, which constituted 31.1% of all reciprocal translocations. The three major indications for amniocentesis with a diagnosis of reciprocal translocation included advanced maternal age (AMA, 52.7%), a parent with an abnormal karyotype (17.6%), and abnormal biochemical markers in the maternal serum (12.2%). For individual types of reciprocal translocations (balanced and unbalanced), except for the presence of abnormal biochemical markers in maternal serum, both AMA and a parent with an abnormal karyotype were primary indications for amniocentesis. However, the highest percentage of reciprocal translocations in all amniocentesis cases was found in cases involving a parent with an abnormal karyotype (5.16%, 13/252).
  
  
  CONCLUSIONS
  Patients with a parent who carries an abnormal karyotype should be encouraged to undergo amniocentesis in prenatal consultation, since the risk of a diagnosis of reciprocal translocation can be particularly high.
authors.affiliation: Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Chang
authors.forename: Peng-Hui
authors.initials: PH
authors.lastname: Wang
authors.forename: Wai Hou
authors.initials: WH
authors.lastname: Li
authors.forename: Ling-Chao
authors.initials: LC
authors.lastname: Chen
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Chang
authors.forename: Pi-Lin
authors.initials: PL
authors.lastname: Sung
authors.forename: Ming-Jie
authors.initials: MJ
authors.lastname: Yang
authors.forename: Ling-Yi
authors.initials: LY
authors.lastname: Cheng
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Lai
authors.forename: Yung-Yung
authors.initials: YY
authors.lastname: Cheng
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Yeh
authors.forename: Wen-Hsun
authors.initials: WH
authors.lastname: Chang
authors.forename: Shiau-You
authors.initials: SY
authors.lastname: Wang
authors.forename: Shang-Rong
authors.initials: SR
authors.lastname: Chen
authors.forename: Ming-Shyen
authors.initials: MS
authors.lastname: Yen
authors.forename: Kuan-Chong
authors.initials: KC
authors.lastname: Chao
mesh_terms: D000328:Adult; D000649:Amniocentesis; D005260:Female; D006801:Humans; D059785:Karyotype; D008423:Maternal Age; D011247:Pregnancy; D012189:Retrospective Studies; D014178:Translocation, Genetic