| Резюме: | Prenatal studies involve techniques to determine the fetal health, of which the non-invasive ones are the most frequent, for example biochemical screenings, studies of fetal cells in maternal blood and ultrasound. If one or more of these non-invasive studies yield a positive result or indicate a high risk of presenting a congenital anomaly, then an invasive study is performed with the aim of reaching an accurate chromosomal diagnosis. Depending on the gestational age, samples of chorionic villus (CV) or amniotic fluid (AL) can be obtained for cytogenetic analysis. The purpose of prenatal cytogenetic diagnosis is to detect chromosomal abnormalities in the fetus. Between weeks 12 and 18 of pregnancy, a VC puncture is performed, which offers the advantage of obtaining rapid results after 7 days from the sample collection and has the disadvantage of presenting higher percentages of false positives and confined placental mosaicism. From week 18 to week 35, amniocentesis is performed. This technique is more representative of fetal tissue and the metaphases obtained are of better quality, but the disadvantage is that the results are only obtained 20 days after sample collection. In this report we present the results of a decade of prenatal cytogenetic studies. The samples were obtained at the Maternal Neonatal Hospital in the city of Posadas, Misiones and analyzed in the cytogenetic laboratory of the IGeHM in the period 2011-2022. In these 11 years, prenatal cytogenetic techniques were standardized from CV and AL. 160 cytogenetic studies were performed, of which cell growth was obtained in 134 cases (84%), and no cell growth in 26 cases (16%). Cytogenetic analysis in 84 cases (53%) showed a normal karyotype and in 50 cases (31%) some chromosomal alteration was found.
The results of pathological cases showed high values with respect to different countries where prenatal diagnosis is performed. Among these, the most frequent were Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Turner syndrome (45,X), Patau syndrome (trisomy 13), as expected and regarding to international literature. We can conclude that prenatal cytogenetic diagnosis is very important for parents who can make a free and informed decision about the ongoing pregnancy, to allow better obstetric management and access to a highly complex neonatology service in addition to psychological and genetic counseling.
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Chromosomal Analysis in a Population Sample of Patients with Reproductive Problems of the Province of Misiones (1990-2019)