Ten-year trends in prevalence of Down syndrome in a developing country: impact of the maternal age and prenatal screening.

OBJECTIVE: This study examines trends in total and live birth prevalence of trisomy 21 (T21) with regard to increasing maternal age and the introduction of prenatal diagnosis in Bosnia and Herzegovina. METHOD: The prenatal detection was introduced in January 2008 in 3 hospitals and assessed until December 31, 2015. In this study, 99 fetuses and 330 babies were diagnosed with T21 in the studied period. RESULTS: On average, each year 33 T21 individuals were born and 13 T21 fetuses were diagnosed prenatally. The calculated incidence for the live born T21 individuals in Bosnia is 1:999. The live-birth prevalence of T21 was 9.6 per 10,000 births and the total prevalence of T21 was 19.1. The total T21 prevalence increases exponentially with the advanced maternal age. Prenatal T21 prevalence is 1.29 per 10,000 births for mothers <35, but increases exponentially with increasing age (32 for >40 years). The most common indications for invasive prenatal testing were ultrasound screening combined with biochemical serum analysis followed by the advanced maternal age. CONCLUSION: The prevalence of liveborn Down syndrome children remained constant. Despite the fact that increasing maternal age in the last decade contributed to the rise in the total T21 prevalence, the effect of the introduction of prenatal diagnosis on the live-birth T21 prevalence of T21 was minimal, leading to the conclusion that the prenatal screening has to be improved in developing countries.

Diagnostics of common microdeletion syndromes using fluorescence in situ hybridization: single center experience in a developing country.

Microdeletion syndromes are caused by chromosomal deletions of less than 5 megabases which can be detected by fluorescence in situ hybridization (FISH). We evaluated the most commonly detected microdeletions for the period from June 01, 2008 to June 01, 2015 in the Federation of Bosnia and Herzegovina, including DiGeorge, Prader-Willi/Angelman, Wolf-Hirschhorn, and Williams syndromes. We report 4 patients with DiGeorge syndromes, 4 patients with Prader-Willi/Angelman, 4 patients with Wolf-Hirschhorn syndrome, and 3 patients with Williams syndrome in the analyzed 7 year period. Based on the positive FISH results for each syndrome, the incidence was calculated for the Federation of Bosnia and Herzegovina. These are the first reported frequencies of the microdeletion syndromes in the Federation of Bosnia and Herzegovina.

Combined use of cytogenetic and molecular methods in prenatal diagnostics of chromosomal abnormalities.

AIM: The aim of prenatal diagnostics is to provide information of the genetic abnormalities of the fetus early enough for the termination of pregnancy to be possible. Chromosomal abnormalities can be detected in an unborn child through the use of cytogenetic, molecular- cytogenetic and molecular methods. In between them, central spot is still occupied by cytogenetic methods. In cases where use of such methods is not informative enough, one or more molecular cytogenetic methods can be used for further clarification. Combined use of the mentioned methods improves the quality of the final findings in the diagnostics of chromosomal abnormalities, with classical cytogenetic methods still occupying the central spot. MATERIAL AND METHODS: Conducted research represent retrospective-prospective study of a four year period, from 2008 through 2011. In the period stated, 1319 karyotyping from amniotic fluid were conducted, along with 146 FISH analysis. RESULTS: Karyotyping had detected 20 numerical and 18 structural aberrations in that period. Most common observed numerical aberration were Down syndrome (75%), Klinefelter syndrome (10%), Edwards syndrome, double Y syndrome and triploidy (5% each). Within observed structural aberrations more common were balanced chromosomal aberrations then non balanced ones. Most common balanced structural aberrations were as follows: reciprocal translocations (60%), Robertson translocations (13.3%), chromosomal inversions, duplications and balanced de novo chromosomal rearrangements (6.6% each). CONCLUSION: With non- balanced aberrations observed in the samples of amniotic fluid, non- balanced translocations, deletions and derived chromosomes were equally represented. Number of detected aneuploidies with FISH, prior to obtaining results with karyotyping, were 6.

Use of Quantitative Fluorescent Polymerase Chain Reaction (QF PCR) in Prenatal Diagnostic of Fetal Aneuploidies in a 17 Month Period in Parallel with Karyotyping.

INTRODUCTION: QF PCR has recently entered diagnostic practice as a possible way to bypass culturing of the fetal cells, as well as to provide a rapid response following amniocentesis. MATERIAL AND METHODS: The effective value of the QF PCR remains a much debated issue, positions ranging from that it makes classic kayotyping obsolete except in special occasions, to that it is no more than a guideline for a mandatory karyotype. Current practices of the gynecology specialists generates samples in such fashion that kariotyping of samples quickly falls behind to the point of obsoleteness, because, by the time a karyotype has been finished, a window of opportunity for termination of pregnancy has closed. RESULTS: QF PCR provides a rapid response alternative, but it is necessary to establish its reproducibility, as well as an algorithm of its use along classic kariotyping. This study contains samples processed in a period from August 1, 2012 to December 31 2013 in both QF PCR and classic karyotype. Object of this study was compare results obtained by two methods, and establish confidence interval of the QF PCR testing. Overall, 661 amniotic fluid samples were processed and typed with QF PCR, out of which 221 were done in parallel with karyiotyping, as an confirmation of results.