Frequency of prenatal determination of 13, 18 and 21 trisomies and link with risk factors

Abstract

The study was conducted in the Laboratory of the Hospital of Lithuanian University of Health Sciences Kaunas Clinic, in the Laboratory of Clinical Chemistry and Genetics and in the Department of Biology of Vytautas Magnus University. Abnormalities of number of chromosomes are diagnosed from amniotic fluid, which is taken by using an invasive prenatal method – amniocentesis, and modern diagnostic methods such as molecular cytogenetic analysis (FISH) and cytogenetic method, diagnosis of karyotype, by using G-staining method. In order to analyse the main risk factors that determine the frequency of Patau, Edwards and Down syndromes in the analysed group and to evaluate the variety of changeovers of chromosomes structure, the retrospective analysis of patient’s case records data was performed. The aforementioned patients were examined in the Hospital of Lithuanian University of Health Sciences Kaunas Clinic in 2007–2011. The received data is processed by using Statistical Package for Social Sciences (T-Test). The aim of the study is to evaluate, by using cytogenetic and molecular cytogenetic research methods, the frequency of prenatal trisomies determination of the thirteenth (13), the eighteenth (18), and the twenty first (21) chromosomes for the patients, who during 2007–2011 had genetic consultations in the Hospital of Lithuanian University of Health Sciences Kaunas Clinics and to determine the connection between these trisomies and risk factors. During 2007–2011 1 156 patients were examined and 49 (4.2%) alterations of karyotype were determined, out of which 30 (61%) are related to Down syndrome, 14 (29%) to Edwards syndrome and 5 (10%) to Patau syndrome. After studying the data of questionnaires and case records, on the basis of the statistical reliability of data analysis, the influence of the main reproductive factors (abortions, contraceptives) and other risk or environmental factors (smoking, genetic diseases and use of medicines) to fetal anomalies was determined.