[Incidental findings of maternal genetic abnormalities during non-invasive prenatal screening]

The non-invasive prenatal test (NIPT) has recently been added in our clinical practice. Sensitivity and specificity of this method in the common fetal aneuploidies screening is about 99 %. This technique remains a screening test, not a diagnosis test, because false positive or negative results exist. The discordant results are explained by the method itself witch analyses the whole free circulating DNA in the maternal blood: the fetal DNA from trophoblastic cells lysing but also the maternal DNA. Placenta confined mosaic is the main false positive cause reported in the literature. NIPT can rarely reveal maternal abnormalities. We are reporting two cases carrying a cytogenetic anomaly revealed with NIPT: microduplication of 22q11.2 and a sexual chromosomes anomaly.