Chromosomal Microarrays in Prenatal Diagnosis: Time for a Change of Policy?
Microarrays have replaced conventional karyotyping as a first-tier test for unbalanced chromosome anomalies in postnatal cytogenetics mainly due to their unprecedented resolution facilitating the detection of submicroscopic copy number changes at a rate of 10-20% depending on indication for testing. A number of studies have addressed the performance of microarrays for chromosome analyses in high risk pregnancies due to abnormal ultrasound findings and reported an excess detection rate between 5% and 10%. In low risk pregnancies, clear pathogenic copy number changes at the submicroscopic level were encountered in 1% or less. Variants of unclear clinical significance, unsolicited findings, and copy number changes with variable phenotypic consequences are the main issues of concern in the prenatal setting posing difficult management questions. The benefit of microarray testing may be limited in pregnancies with only moderately increased risks (advanced maternal age, positive first trimester test). It is suggested to not change the current policy of microarray application in prenatal diagnosis until more data on the clinical significance of copy number changes are available.
Medical Genetics, Department of Biomedicine, University Hospital Basel, Burgfelderstr. 101, Building J, CH-4055 Basel, Switzerland. peter.miny@unibas.ch.
Peter
P
Miny
Medical Genetics, Department of Biomedicine, University Hospital Basel, Burgfelderstr. 101, Building J, CH-4055 Basel, Switzerland. friedel.wenzel@usb.ch.
Friedel
F
Wenzel
Ultraschall Freie Strasse, Freie Strasse 38, CH-4001 Basel, Switzerland. sevgi.tercanli@unibas.ch.
Sevgi
S
Tercanli
Medical Genetics, Department of Biomedicine, University Hospital Basel, Burgfelderstr. 101, Building J, CH-4055 Basel, Switzerland. isabel.filges@unibas.ch.|Department of Medical Genetics, Box 153, BC Children's and Women's Hospital, 4480 Oak Street, Vancouver BC, V6H 3V4, Canada. isabel.filges@unibas.ch.
Isabel
I
Filges
array CGH; microarrays; prenatal diagnosis