OC05.07: Pathologic copy number variations ( CNVs ) in fetuses with a normal karyotype: does the indication for testing matter?
Year: 2015
Type: conference-abstract
Abstract: To assess the likelihood of pathologic CNVs based on the specific indication for chromosomal microarray analysis (CMA). We performed a retrospective analysis of amniocentesis and CVS results obtained during a 4-year period in a single center. 3314 consecutive patients undergoing invasive genetic testing were offered CMA in addition to standard karyotype. 2026 (61%) elected to also pursue CMA. The prevalence of pathologic CNVs [abnormal CNV or variants of unknown significance (VOUS) – likely abnormal] was compared between patients with low-risk indications (AMA or parental desire) and those with high-risk indications (sonographic abnormalities, abnormal aneuploidy screen, personal or familial history of genetic conditions). Likewise, the prevalence of pathologic CNVs in patients with different sonographic abnormalities was calculated and compared to the low-risk group. Chi-square and Fisher's exact tests were used for statistical analysis. Summary of the results is presented in table 1. The prevalence of pathologic CNVs was significantly higher in patients with high-risk indications and specifically sonographic abnormalities, relative to the low-risk group (all p < 0.05). Prenatal CMA detected clinically relevant CNVs in a substantial number of fetuses with a normal karyotype. Major structural malformations and NT ≥ 3.0mm are associated with the highest risk for a CMA abnormality. Additionally, the prevalence of pathologic CNVs in the low-risk population is high enough (1:250) to suggest genetic counselling even in this group.
DOI: 10.1002/uog.14984
Institutions: Lenox Hill Hospital, Baylor College of Medicine
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2109727704