[Noninvasive fetal sex detection from maternal plasma in pregnant women]. / Neinvazivní detekce gonozomálních DNA sekvencí v plazme gravidních zen s vyuzitím kapilární elektroforézy.

OBJECTIVE: Objective of our study was optimization of noninvasive fetal sex detection from maternal plasma in pregnant women. STUDY DESIGN: Molecular DNA quantitative analyses in gonosomal loci. SETTING: The study was performed at Department of Medical Genetics and Fetal Medicine, University Hospital Olomouc. METHODS: Together 475 DNA samples isolated from maternal plasma in different weeks of pregnancy ranging from 4th w.g. to 37th w.g. Y chromosomal sequences in AMELY and TSPY were tested by refined quantitative fluorescent PCR using capillary electrophoresis. RESULTS: The method is able to distinguish 1% of Y chromosomal sequences of artificial mixtures. Investigation and assessment in cell free fetal DNA samples achieved 4.05% of false positivity and 7.15% of false negativity in Y sequence detection. CONCLUSION: Established method allows detecting fetal sex with high sensitivity and specificity. The method is possible to use also for quantitative purposes.

[Advanced maternal age as an indication for invasive prenatal diagnostics?]. / Vyssí vek matky jako indikace k invazivní prenatální diagnostice?

OBJECTIVES: To investigate the effectivity of the first trimester screening (FTS), age and other factors as an indication for invasive testing. METHODS: A retrospective analysis of indications for invasive procedures and their effectivity in the group of women who underwent screening in the first trimester of pregnancy in our center. Women were offered the combined screening program by ultrasound and biochemical markers. Women with risk more than 1 : 300 for chromosome 21, 18 or 13 trisomies, or those over the age of 35 as this is still and indication for invasive tests in the Czech Republic were offered genetic counseling and invasive testing. Chorionic villous sampling (CVS) or amniocentesis (AMC) was than performed. RESULTS: Of the 1700 women who underwent FTS, 291 were over 35 in which only 24 had a risk higher than 1 : 300. Detection rate of trisomy 21, 18 and 13 were 100%, (16 cases) for a false positive rate of 4.6%. In the whole screened population 79 had a risk more than 1 : 300. The total number of invasive tests was 150. Amniocentesis was performed in 88 cases, only 27 were done on the basis of screening with 3 aneuploidy detected. 36 amniocenteses were done for age and 25 for other indications-- all had normal karyotype. The CVS was performed in 62, 52 on the basis of screening with 13 aneuploidy detected. In the other ten cases 5 for age and 5 for family history the karyotype was normal. CONCLUSION: Altogether 79 invasive procedures based on screening detected all 16 aneuploidies. Remaining 71 invasive tests (n = 41) for age and (n = 30) for other indications had a complete normal karyotype.

[Efficiency of measuring nasal bone as an ultrasound marker of Down syndrome in 11th to 13th+6 week of pregnancy]. / Efektivita merení nosní kosti jako UZ markeru pro Downuv syndrom v 11.-13(+6). týdnu gravidity.

OBJECTIVES: The aim of this study is to evaluate the significance of nasal bone as a marker for trisomy 21 in the group of women that underwent invasive procedures in our center at 11 to 14 weeks' gestation. METHODS: The data of 181 women who had undergone the invasive procedures were evaluated for the presence or absence of nasal bone retrospectively and were correlated with fetal karyotype. RESULTS: A successful view of the fetal profile was obtained in 135 fetuses. The nasal bone was absent in 5 of 8 fetuses with trisomy 21 and in 3 of 4 fetuses with trisomy 18. In the group of chromosomally normal fetuses the nasal bone was absent in 4 of the 123 cases. The false positive rate of our screening program dropped from 4.5% to 2.5% after the introduction of the nasal bone evaluation into our risk calculation model for trisomy 21. CONCLUSION: Nasal bone evaluation improved the detection of trisomy 21 in the first trimester in our screening program and reduced the need for invasive procedures in our department. Absence of the nasal bone showed a sensitivity of 63% for a 5% false positive rate for trisomy 21 in our study. It is rarely observed in chromosomally normal fetuses (2.5%). An appropriate training is mandatory in order to achieve acceptable results.

[OSCAR (one-stop clinic for assessment of fetal risk): our experience with first trimester screening for chromosomal abnormalities]. / OSCAR (one stop clinic) pro zhodnocení rizika fetálnch abnormalit: dvouletá zkusenost uzívání screeningu chromozomálních abnormalit v I. trimestru gravidity.

OBJECTIVES: In recent years has been intensified an effort to develop early more exact non-invasive methods for prenatal diagnosis. We report our experience to screen trisomy 21 and other chromosomal abnormalities in the first trimester in so-called OSCAR (One-Stop Clinic for Assessment of Fetal Risk). DESIGN AND SETTING: It is a retrospective study held at the Department of Medical Genetic and Fetal Medicine, Teaching Hospital, Olomouc. METHODS: A group of 2110 pregnant women has been screened by maternal age as a background risk, fetal nuchal translucency, nasal bone as ultrasound markers as well as maternal serum level of free beta-subunit human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) as a biochemical markers between 11 - 13+6 weeks of pregnancy from January 2004 to December 2005. The Fetal Medicine Foundation Guidelines and software were the methods and tools used for screening. Karyotyping by chorionic villous sampling or amniocentesis was offered to women with risks > or = 1 in 300. RESULTS: We reported 100% sensitivity for this method for a 4, 6% false positive. There was detected 21 chromosomal abnormalities in which 10 were trisomy 21. This is the first result to be published for this screening method in the Czech Republic. CONCLUSION: In our experience first trimester screening for trisomy 21 and other aneuploidies has a high sensitivity with a low false positive rate and can be delivered in an efficient manner in a one-stop multidisciplinary clinic.

[Rapid detection of most frequent chromosomal aneuploidies by the multiplex QF PCR method in the first trimester of pregnancy]. / Rychlá detekce nejcastejsích chromozomálních aneuploidií metodou multiplex QF PCR v prvním trimestru gravidity.

OBJECTIVE: Rapid detection of most frequent aneuploidies by the multiplex QF PCR method in non-cultured samples of chorial tissue. Summarized results of QF PCR method applied in the management of care of pregnant women in the first trimester of pregnancy. TYPE OF STUDY: An original contribution. SETTING: Institute of Medical Genetics and Fetal Medicine, Faculty Hospital and Medical Faculty, Palacky University Olomouc. METHODS: The samples of chorial tissue were obtained from 101 pregnant women. Non-cultured samples were processed by the multiplex QF PCR method. STR loci of chromosomes 13, 18, 21 and X and Y were analyzed. These markers were amplified in two separate multiplex PCR reactions under the same conditions and subjected to fragmentation analysis in capillary electrophoresis. RESULTS: All 101 analyzed samples of chorial tissue were successfully amplified. In this group, 16 pathologies of the fetuses were detected by the multiplex QF PCR method. Triploidy was detected in two cases, trisomy of chromosome 21--Down syndrome was found in seven cases, and trisomy of chromosome 18--Edwards syndrome was found in six cases and monosomy of gonosome X--the Turner' s syndrome was revealed once. CONCLUSIONS: The multiplex QF PCR method is an indispensable part of the screening of the first trimester and provides a rapidly available and reliable result in the examined patients.

[Analysis of free foetal DNA in maternal plasma using STR loci]. / Analýza volné fetální DNA v maternální plazme s vyuzitím STR lokusu.

BACKGROUND: Problems of maternal and foetal genotype differentiation of maternal plasma in pregnant women are solved generally by real-time systems. In this case the specific probes are used to distinguish particular genotype. Mostly gonosomal sequences are utilised to recognise the male foetus. This work describes possibilities in free foetal DNA detection and quantification by STR. METHODS AND RESULTS: Artificial genotype mixtures ranging from 0,2 % to 100 % to simulate maternal and paternal genotypes and 27 DNA samples from pregnant women in different stage of pregnancy were used for DNA quantification and detection. Foetal genotype was confirmed by biological father genotyping. The detection was performed in STR from 21st chromosome Down syndrome (DS) responsible region by innovated (I) QF PCR which allows to reveal and quantify even very rare DNA mosaics. The STR quantification was assessed in artificial mixtures of genotypes and discriminability of particular genotypes was on the level of few percent. Foetal DNA was detected in 74 % of tested samples. CONCLUSIONS: The IQF PCR application in quantification and differentiation between maternal and foetal genotypes by STR loci could have importance in non-invasive prenatal diagnostics as another possible marker for DS risk assessment.