Noninvasive prenatal screening for the most common aneuploidies

Prenatalna dijagnostika kromosomopatija neizostavan je dio prenatalne skrbi, a provodi se tijekom prvog i drugog tromjesečja trudnoće te uključuje brojne invazivne i neinvazivne metode. Neinvazivnim metodama probira utvrđuje se rizik za aneuploidije u ploda dok se invazivnim metodama dijagnostički potvrđuje ili isključuje kromosomska promjena. Neinvazivna metoda prenatalnog probira koja s visokom pouzdanošću može utvrditi rizik za najčešće aneuploidije kromosoma danas je neinvazivno prenatalno testiranje slobodno cirkulirajuće DNA fetusa iz krvi majke (NIPT). Cilj ovoga rada je prezentirati rezultate NIPT-a koji se provodio na Zavodu za medicinsku biologiju i genetiku Medicinskog fakulteta Sveučilišta u Rijeci u razdoblju od siječnja 2019. godine do prosinca 2021. godine. U navedenom periodu, NIPT analizu napravile su 63 ispitanice, uz razvidan godišnji porast broja ispitanica. Između udjela fetalne frakcije i tjedna trudnoće, indeksa tjelesne mase i dobi majke nije utvrđena statistički značajna povezanost. NIPT je u 54% slučajeva bio samostalna indikacija za citogenetičku analizu stanica plodove vode, a slijedile su ga kombinacija NIPT-a i UZV-a te kombinacija NIPT-a i dobi trudnice. Najveću točnost u procjenjivanju rizika za aneuploidiju ploda imala je kombinacija NIPT-a i UZV-a. Usporedbom rezultata NIPT analize i citogenetičke analize stanica plodove vode, utvrđeno je da je NIPT u 33,3% slučajeva imao lažno pozitivne rezultate. NIPT analiza bila je najpouzdanija u procjenjivanju rizika za trisomiju kromosoma 21 dok je u procjeni aneuploidija spolnih kromosoma bila manje pouzdana. Invazivne metode i nadalje ostaju temelj dijagnostike kromosomskih abnormalnosti u prenatalnom razdoblju.Prenatal diagnosis of chromosomopaties is an indispensable part of prenatal care, and is performed during the first and second trimester of pregnancy. It includes a number of invasive and non-invasive methods. Non-invasive screening methods determine the risk of aneuploidies in the fetus, while invasive methods diagnostically confirm or exclude chromosomal changes. A non-invasive method of prenatal screening that can reliably determine the risk of the most common chromosome aneuploidies today is non-invasive prenatal testing of cell-free circulating fetal DNA from the mother's blood (NIPT). The aim of this paper is to present the results of the NIPT conducted at the Department of Medical Biology and Genetics, Faculty of Medicine, University of Rijeka in the period from January 2019 to December 2021. In this period, the NIPT analysis was performed by 63 respondents, with a clear annual increase in the number of respondents. No statistically significant correlation was found between the proportion of fetal fraction and week of pregnancy, body mass index and maternal age. In 54% of cases, NIPT was an independent indication for cytogenetic analysis of amniotic fluid cells, followed by a combination of NIPT and ultrasound and a combination of NIPT and the age of the pregnant woman. The combination of NIPT and ultrasound had the highest accuracy in assessing the risk of fetal aneuploidy. When comparing the results of NIPT analysis and cytogenetic analysis of amniotic fluid cells, it was found that NIPT had false positive results in 33.3% of cases. NIPT analysis was the most reliable in assessing the risk for trisomy 21 while in assessing sex chromosome aneuploidies, it was less reliable. Altogether, invasive methods continue to be the basis for the diagnosis of chromosomal abnormalities in the prenatal period