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PLoS One. 2014 Feb 5;9(2):e87988. doi: 10.1371/journal.pone.0087988. eCollection 2014.

Whole-genome array CGH evaluation for replacing prenatal karyotyping in Hong Kong.

Author information

1
Department of Obstetrics and Gynaecology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China ; Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
2
Department of Obstetrics and Gynaecology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
3
Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
4
Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China ; Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
5
Department of Obstetrics and Gynaecology, Queen Elizabeth Hospital, Hong Kong Special Administrative Region, China.
6
Department of Obstetrics and Gynaecology, Kwong Wah Hospital, Hong Kong Special Administrative Region, China.

Abstract

OBJECTIVE:

To evaluate the effectiveness of whole-genome array comparative genomic hybridization (aCGH) in prenatal diagnosis in Hong Kong.

METHODS:

Array CGH was performed on 220 samples recruited prospectively as the first-tier test study. In addition 150 prenatal samples with abnormal fetal ultrasound findings found to have normal karyotypes were analyzed as a 'further-test' study using NimbleGen CGX-135K oligonucleotide arrays.

RESULTS:

Array CGH findings were concordant with conventional cytogenetic results with the exception of one case of triploidy. It was found in the first-tier test study that aCGH detected 20% (44/220) clinically significant copy number variants (CNV), of which 21 were common aneuploidies and 23 had other chromosomal imbalances. There were 3.2% (7/220) samples with CNVs detected by aCGH but not by conventional cytogenetics. In the 'further-test' study, the additional diagnostic yield of detecting chromosome imbalance was 6% (9/150). The overall detection for CNVs of unclear clinical significance was 2.7% (10/370) with 0.9% found to be de novo. Eleven loci of common CNVs were found in the local population.

CONCLUSION:

Whole-genome aCGH offered a higher resolution diagnostic capacity than conventional karyotyping for prenatal diagnosis either as a first-tier test or as a 'further-test' for pregnancies with fetal ultrasound anomalies. We propose replacing conventional cytogenetics with aCGH for all pregnancies undergoing invasive diagnostic procedures after excluding common aneuploidies and triploidies by quantitative fluorescent PCR. Conventional cytogenetics can be reserved for visualization of clinically significant CNVs.

PMID:
24505343
PMCID:
PMC3914896
DOI:
10.1371/journal.pone.0087988
[Indexed for MEDLINE]
Free PMC Article

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