Due to the examination method non-invasive prenatal testing has certain limits. Therefore please inform your patients about these limitations as follows:<\/p>\n\n\n\n
In general, no statements regarding structural chromosomal changes, mosaics or polyploidy can be made with the PrenaTest®<\/sup>.<\/p>\n\n\n\n The examined fetal DNA is primarily derived from the cytotrophoblast and is released by apoptosis and necrosis of trophoblast cells of the placenta. As such, it is only possible to achieve a level of diagnostic certainty close to that attained via direct chorionic villus sampling. Consequently, mosaics or fetoplacental discrepancies in trisomies 21, 18 or 13 resp. gonosomal aneuploidy are not recognisable. In the event of a fetoplacental discrepancy, this can also mean that the PrenaTest®<\/sup> result is not representative for the unborn child.<\/p>\n\n\n\n Undisclosed vanished twins<\/em> can contribute a sufficient proportion to the total cffDNA fraction to cause a positive PrenaTest®<\/sup> result being not representative for the continuing singleton pregnancy.<\/p>\n\n\n\n An existing maternal mosaic can lead to a conspicuous PrenaTest®<\/sup> result which may not representative for the unborn child. These mosaics primarily affect gonosomal aneuploidy. For example, cases of pregnancies in women affected with Turner syndrome were based on mosaic findings (45, X\/46, XX) in the women.<\/p>\n\n\n\n An existing maternal gonosomal aneuploidy as the Triple X syndrome can lead to a conspicuous PrenaTest®<\/sup> result which may not be representative for the unborn child. This means, for example, that a positive PrenaTest®<\/sup> result with a reference to a chromosome disorder 47, XXY does not necessarily represent a fetal chromosomal abnormality. Rather, it should be examined whether and how the pregnant woman has a triple X syndrome.<\/p>\n\n\n\n Maternal tumors, copy number variants (CNV), as well as rare genetic modifications in the examined gene regions, can very rarely lead to a discordant PrenaTest®<\/sup> result, which is not representative for the unborn child.<\/p>\n\n\n\n It is possible that the mother is the carrier of the 22q11.2 microdeletion, associated with the DiGeorge syndrome and velo-cardio-facial syndrome (Shpintzen syndrome) but not the unborn child. This can lead to discordant (false-positive) test results.<\/p>\n\n\n\n In more than 85% of the affected persons, the deletion includes a region measuring approx. 2.5 megabases in the 22q11.2 region of chromosome 22. This region is investigated with the PrenaTest®<\/sup>. A small percentage of affected persons has an even smaller deletion or point mutation in the affected region which cannot be detected with the PrenaTest®<\/sup>. This can lead to discordant (false-negative) test results.<\/p>\n","protected":false},"excerpt":{"rendered":" Limitations of non-invasive prenatal tests (NIPT) Due to the examination method non-invasive prenatal testing has certain limits. Therefore please inform your patients about these limitations as follows: Structural chromosomal changes, mosaics and polyploidy In general, no statements regarding structural chromosomal changes, mosaics or polyploidy can be made with the PrenaTest®. Fetal mosaics, fetoplacental discrepancies The Fetal mosaics, fetoplacental discrepancies<\/h3>\n\n\n\n
Vanishing Twin<\/h3>\n\n\n\n
Maternal mosaic<\/h3>\n\n\n\n
Maternal gonosomal aneuploidy<\/h3>\n\n\n\n
Other maternal genetic disorders<\/h3>\n\n\n\n
Mother is carrier of the 22q11.2 microdeletion<\/h3>\n\n\n\n
Size of the microdeletion<\/h3>\n\n\n\n
… read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":457,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"inline_featured_image":false,"ghostkit_customizer_options":"","ghostkit_custom_css":"","ghostkit_custom_js_head":"","ghostkit_custom_js_foot":"","ghostkit_typography":""},"acf":[],"_links":{"self":[{"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/pages\/440"}],"collection":[{"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/comments?post=440"}],"version-history":[{"count":0,"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/pages\/440\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/pages\/457"}],"wp:attachment":[{"href":"https:\/\/www.praenaforyou.com\/en\/wp-json\/wp\/v2\/media?parent=440"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}