TY - JOUR
T1 - Enlarged NT (>= 3.5 mm) in the first trimester - not all chromosome aberrations can be detected by NIPT
AU - Srebniak, Gosia
AU - Wit, Charlotte
AU - Diderich, Karin
AU - Govaerts, LCP
AU - Joosten, Marieke
AU - Knapen, Maarten
AU - Bos, Marnix
AU - Bruinsma, Gerda
AU - Koningen, Mieke
AU - Go, Attie
AU - Galjaard, Robert-Jan
AU - Opstal, D
PY - 2016
Y1 - 2016
N2 - Background: Since non-invasive prenatal testing (NIPT) in maternal blood became available, we evaluated which chromosome aberrations found in our cohort of fetuses with an enlarged NT in the first trimester of pregnancy (tested with SNP microarray) could be detected by NIPT as well. Method: 362 fetuses were referred for cytogenetic testing due to an enlarged NT (>= 3.5 mm). Chromosome aberrations were investigated using QF-PCR, karyotyping and whole genome SNP array. Results: After invasive testing a chromosomal abnormality was detected in 137/362 (38 %) fetuses. 100/362 (28 %) cases concerned trisomy 21, 18 or 13, 25/362 (7 %) an aneuploidy of sex chromosomes and 3/362 (0.8 %) triploidy. In 6/362 (1.6 %) a pathogenic structural unbalanced chromosome aberration was seen and in 3/362 (0.8 %) a susceptibility locus for neurodevelopmental disorders was found. We estimated that in 2-10 % of fetuses with enlarged NT a chromosome aberration would be missed by current NIPT approaches. Conclusion: Based on our cohort of fetuses with enlarged NT we may conclude that NIPT, depending on the approach, will miss chromosome aberrations in a significant percentage of pregnancies. Moreover all abnormal NIPT results require confirmatory studies with invasive testing, which will delay definitive diagnosis in ca. 30 % of patients. These figures are important for pretest counseling enabling pregnant women to make informed choices on the prenatal test. Larger cohorts of fetuses with an enlarged NT should be investigated to assess the additional diagnostic value of high resolution array testing for this indication.
AB - Background: Since non-invasive prenatal testing (NIPT) in maternal blood became available, we evaluated which chromosome aberrations found in our cohort of fetuses with an enlarged NT in the first trimester of pregnancy (tested with SNP microarray) could be detected by NIPT as well. Method: 362 fetuses were referred for cytogenetic testing due to an enlarged NT (>= 3.5 mm). Chromosome aberrations were investigated using QF-PCR, karyotyping and whole genome SNP array. Results: After invasive testing a chromosomal abnormality was detected in 137/362 (38 %) fetuses. 100/362 (28 %) cases concerned trisomy 21, 18 or 13, 25/362 (7 %) an aneuploidy of sex chromosomes and 3/362 (0.8 %) triploidy. In 6/362 (1.6 %) a pathogenic structural unbalanced chromosome aberration was seen and in 3/362 (0.8 %) a susceptibility locus for neurodevelopmental disorders was found. We estimated that in 2-10 % of fetuses with enlarged NT a chromosome aberration would be missed by current NIPT approaches. Conclusion: Based on our cohort of fetuses with enlarged NT we may conclude that NIPT, depending on the approach, will miss chromosome aberrations in a significant percentage of pregnancies. Moreover all abnormal NIPT results require confirmatory studies with invasive testing, which will delay definitive diagnosis in ca. 30 % of patients. These figures are important for pretest counseling enabling pregnant women to make informed choices on the prenatal test. Larger cohorts of fetuses with an enlarged NT should be investigated to assess the additional diagnostic value of high resolution array testing for this indication.
U2 - 10.1186/s13039-016-0279-z
DO - 10.1186/s13039-016-0279-z
M3 - Article
VL - 9
JO - Molecular Cytogenetics
JF - Molecular Cytogenetics
SN - 1755-8166
ER -