title: [Application of chromosome microarray analysis for fetuses with increased nuchal translucency and a normal karyotype].
abstract: OBJECTIVE
  To explore the genetic etiology for fetuses with increased nuchal translucency (NT) but a normal karyotype at whole genome level by chromosome microarray analysis (CMA).
  
  
  METHODS
  Seventy-eight fetuses with increased NT (≥ 3.0 mm) but a normal karyotype were collected between 11(+0) and 13(+6) gestational weeks. Genomic DNA was extracted, and microarray testing was performed using Affymetrix CytoScan(TM) HD arrays. The data was analyzed by CHAS software. All detected copy number variations (CNVs) were confirmed with real-time quantitative polymerase chain reaction.
  
  
  RESULTS
  The CMA assay has detected pathogenic CNVs in 6 fetuses (7.69%), which have ranged from 0.41 Mb to 15.87 Mb. Well-known microdeletion or microduplication syndromes including Wolf-Hirschhorn syndrome, 22q11 microdeletion syndrome and ATR-16 syndrome were identified in three cases. The detection rates in fetuses with or without structural abnormalities were 18.18% and 5.97%, respectively (P=0.198 with Fisher's Exact Test). The average NT in fetuses with pathogenic CNVs and non-pathogenic CNVs has measured 4.48 mm and 4.22 mm (P=0.735 by Mann-Whitney Test).
  
  
  CONCLUSIONS
  For fetuses with increased NT, CMA can identify chromosomal microdeletion/microduplication unrecognizable by conventional karyotyping analysis. It may therefore play an important role in prenatal diagnosis and genetic counseling by improving the diagnostic rate.
authors.affiliation: Prenatal Diagnostic Center, Women and Children's Medical Center of Guangzhou, Guangzhou Medical University, Guangzhou, Guangdong 510623, P.R.China. canliao@hotmail.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Fang
authors.initials: F
authors.lastname: Fu
authors.forename: Ru
authors.initials: R
authors.lastname: Li
authors.forename: Yongling
authors.initials: Y
authors.lastname: Zhang
authors.forename: Junhui
authors.initials: J
authors.lastname: Wan
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.forename: Min
authors.initials: M
authors.lastname: Pan
authors.forename: Li
authors.initials: L
authors.lastname: Zhen
authors.forename: Can
authors.initials: C
authors.lastname: Liao
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations; D025063:Chromosome Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics*; D006801:Humans; D059785:Karyotype; D007621:Karyotyping; D048208:Nuchal Translucency Measurement; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D011296:Prenatal Diagnosis