• Journal of Genetic Medicine
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• v.11 no.2
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• pp.43-48
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• 2014

Chorionic villus sampling has gained importance as a tool for early cytogenetic diagnosis with a shift toward first trimester screening. First trimester screening using nuchal translucency and biomarkers is effective for screening. Chorionic villus sampling generally is performed at 10-12 weeks by either the transcervical or transabdominal approach. There are two methods of analysis; the direct method and the culture method. While the direct method may prevent maternal cell contamination, the culture method may be more representative of the true fetal karyotype. There is a concern for mosaicism which occurs in approximately 1% of cases, and mosaic results require genetic counseling and follow-up amniocentesis or fetal blood sampling. In terms of complications, procedure-related pregnancy loss rates may be the same as those for amniocentesis when undertaken in experienced centers. When the procedure is performed after 9 weeks gestation, the risk of limb reduction is not greater than the risk in the general population. At present, chorionic villus sampling is the gold standard method for early fetal karyotyping; however, we anticipate that improvements in noninvasive prenatal testing methods, such as cell free fetal DNA testing, will reduce the need for invasive procedures in the near future.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.35-43
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• 2011

Purpose: We evaluated indications for chorionic villus sampling (CVS), the positive predictive value of CVS for fetal chromosomal abnormalities, and the fetal loss rate after CVS at CHA Medical Center. Materials and Methods: We reviewed the medical records of 511 cases of CVS performed between 67 and 120 days of gestation for prenatal cytogenetic diagnosis from April 2000 to April 2010. Fetal karyotypes were obtained by direct and indirect culture methods. Results: The most common indications for CVS were abnormal ultrasonic findings including increased nuchal translucency (294/635, 46.3%). The positive predictive value of abnormal karyotyping according to indication for CVS was highest in cases with abnormal parental karyotypes (14/21, 66.7%). Mosaicism revealed by CVS comprised 3.1% of the sample (16/509). Amniocentesis revealed two cases of true mosaicism and 11 cases of confined placental mosaicism. The fetal loss rate within 4 weeks of the procedure was 1.2% (6/511). Conclusion: If CVS is performed by an expert clinician, it is a feasible and reliable procedure for prenatal genetic diagnosis. When CVS indicates mosaicism, the finding should be confirmed by amniocentesis to distinguish true mosaicism from confined placental mosaicism.

• Journal of Genetic Medicine
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• v.17 no.2
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• pp.68-72
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• 2020

Purpose: Trisomy 21, the cause of Down syndrome (DS) with various medical problems, is the most common aneuploidy during the fetal period. For diagnosis, a non-invasive screening test using maternal blood, which cannot be confirmed and invasive confirmation test with a risk of miscarriage, may be performed. The trophoblast retrieval and isolation of the cervix (TRIC) have been proposed by some researchers as an alternative to overcome the limitations of current tests. We experimented using TRIC to identify the possibility of trisomy 21 for the first time in Asia. Materials and Methods: Three cases of DS were analyzed confirmed by invasive tests (chorionic villus sampling, amniocentesis). All samples of trophoblasts immediately were immersed in phosphate-buffered saline and processed with formalin for fixation. The trophoblasts were isolated using an anti-human leukocyte antigen-G antibody coupled to magnetic nanoparticles. β-human chorionic gonadotropin (hCG)-expressing cells were considered as trophoblast cells, and the detection rate calculated. DS was confirmed by fluorescence in situ hybridization (FISH). Results: The mean trophoblast detection rate using β-hCG was 78.1%, and the detection rate using FISH was 22.2%. In all cases, the trisomy of chromosome 21 was identified. Conclusion: Trophoblast can be obtained from the five weeks of gestation and has a high detection rate, so it is noted that it can replace the current prenatal genetic test. To realize the clinical application as a prenatal genetic test, we will need additional efforts to identify trisomy 21 as well as other chromosomal abnormalities in future large-scale studies.

• Journal of Genetic Medicine
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• v.10 no.2
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• pp.104-108
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• 2013

Purpose: This study was designed to confirm whether the paracentric inversions of fetuses and parents may be harmless. Materials and methods: We report 10 cases (0.14%) with paracentric inversions among 7,181 prenatal cases observed during prenatal diagnosis performed at Cheil General Hospital between January 2009 and June 2013. We used cytogenetic GTL- and RBG-banding techniques. Results: Of the 10 cases, nine cases were transmitted from each of the parents, and one case was de novo. Nine cases were phenotypically normal up to one month of age after birth. One case was lost to follow-up. We present prenatal diagnosis and follow-up examination of the fetuses with paracentric inversion. Conclusion: Based on our cases, most paracentric inversions are considered to be harmless. The precise identification of paracentric inversions might be clinically important and helpful for genetic counseling.

• Korea journal of population studies
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• v.7 no.1
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• pp.78-123
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• 1984

This study is attempting to examine the possible determinants of the rise of the sex ratio at birth from 106 to 110 in past decade in Taiwan. The basic hypothesis for the sudden rise of the sex ratio at birth is due to a combination of prenatal sex determination and abortion. The reasoning for this hypothesis involves three types of considerations - motivation, norm, and access. The theory is evaluated by analyzing data from birth registration and a large and representative sampie of Taiwanese wives of childbearing age. The empirical data seem to support the theoretical preposition and the basic hypothesis that the rise of the sex ratio at birth in Taiwan is due to a combination of prenatal sex determination and abortion. There is striking evidence of son-preference in the rise of the sex ratio at birth in higher birth order. In 1990 the sex ratio was 119 for third births and 128 for fourth and fifth births compared to the expected 106. Also, the 1991 KAP data indicated that women who have only daughters but no any son are more likely to make prenatal sex screening and terminate their pregnancies in male live births at higher birth order. Obviously, genetic diagnosis through chorionic villus sampling which was available in recent years was misused for prenatal sex determination and sex selective abortion.

• Journal of Genetic Medicine
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• v.15 no.1
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• pp.43-47
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• 2018

Partial hydatidiform mole and coexisting fetus is a rare entity with antecedent high risk of maternal and fetal complications, and risk of persistent trophoblastic disease in later life. Here, we report a case of twin pregnancy with live fetus identified as 45,X and normal placenta and another partial mole. Ultrasound scan at 10 weeks showed a hydrops fetus with a focal area of multicystic placenta. The patient underwent chorionic villus sampling and amniocentesis for chromosomal analysis, and the result was 45,X. Based on these finding, the patient then underwent induced abortion. Pathological examination (immunohistochemical staining) of the placenta confirmed the partial mole. This report suggests that careful prenatal ultrasonography and appropriate karyotyping in a molar pregnancy and coexisting fetus enable early diagnosis and may be beneficial for prognosis.

• Korea journal of population studies
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• v.17 no.2
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• pp.98-115
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• 1994

This study is attempting to examine the possible determinants of the rise of the sex ratio at birth from 106 to 110 in past decade in Taiwan. The basic hypothesis for the sudden rise of the sex ratio at birth is due to a combination of prenatal sex determination and abortion. The reasoning for this hypothesis involves three types of considerations - motivation, norm, and access. The theory is evaluated by analyzing data from birth registration and a large and representative sampie of Taiwanese wives of childbearing age. The empirical data seem to support the theoretical preposition and the basic hypothesis that the rise of the sex ratio at birth in Taiwan is due to a combination of prenatal sex determination and abortion. There is striking evidence of son-preference in the rise of the sex ratio at birth in higher birth order. In 1990 the sex ratio was 119 for third births and 128 for fourth and fifth births compared to the expected 106. Also, the 1991 KAP data indicated that women who have only daughters but no any son are more likely to make prenatal sex screening and terminate their pregnancies in male live births at higher birth order. Obviously, genetic diagnosis through chorionic villus sampling which was available in recent years was misused for prenatal sex determination and sex selective abortion.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.2
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• pp.201-206
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• 1994

Down syndrome is one of the major chromosomal anomalies in Korea. To decrease incidence of Down syndrome, antenatal diagnosis is essential. At present, antenatal diagnosis of Down syndrome is done by karyotyping from chorionic villus sampling, amniocentesis, and cordocentsis. All these methods have some problems such as a risk of abortion, a long waiting time, difficulties in sampling, and so on. The aim of study was to confirm that PCR(Polymerase Chain Reaction) using D21S11 primer could be a diagnostic tool for Down syndrome. PCR using D21S11 primers with $^{32}P$ labeling at 5' end was done in 21 cases of DNA from 21 Trisomy and 20 cases of DNA from normal karyotype. PCR product was running for 10 hours on the 6% polyacrylamide gel under 1,000 V or for 8 hours under 1,500 V. After X-ray film exposure, it was read by densitometry. Normal group showed 1: 1 band or single band. 21 Trisomy group showed 1.3-2: 1 band or 2.3 times of density compared to normal single band or 3 bands. This method gave the result within 24 hours. It can be an useful diagnostic tool to detect 21 Trisomy antenatally, especially in late pregnancy, and in preimplantation diagnosis.

• Journal of Genetic Medicine
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• v.11 no.1
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• pp.16-21
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• 2014

A 31-year-old woman, who was pregnant with twins, underwent chorionic villus sampling because of increased nuchal translucency in one of the fetuses. Cytogenetic analysis showed a normal karyotype in the fetus with increased nuchal translucency. However, the other fetus, with normal nuchal translucency, had a derivative X chromosome (der(X)). For further analysis, fluorescence in situ hybridization (FISH) and additional molecular studies including fragile X analysis were performed. FISH analysis confirmed that the Y chromosome was the origin of extra segment of the der(X). The X-chromosome breakpoint was determined to be at Xq27 by FMR1 CGG repeat analysis, and the Y-chromosome breakpoint was determined to be at Yq11.23 by the Y chromosome microdeletion study. To predict the fetal outcome, the X-inactivation pattern was examined, and it revealed non-random X inactivation of the der(X). To the best of our knowledge, the identification of an unbalanced Xq;Yq translocation at prenatal diagnosis has never been reported. This study was performed to identify precise breakpoints and the X-inactivation pattern as well as to provide the parents with appropriate genetic counseling.

• Journal of Genetic Medicine
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• v.15 no.1
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• pp.8-12
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• 2018

Purpose: This study aimed to investigate fetal ultrasonographic findings in cases of prenatally diagnosed de novo balanced translocations and the role of fetal ultrasound in prenatal genetic counseling. Materials and Methods: We collected cases with de novo balanced translocations that were confirmed in chorionic villus sampling, amniocentesis, and cordocentesis between 1995 and 2016. A detailed, high-resolution ultrasonography was performed for prediction of prognosis. Chromosomes from the parents of affected fetuses were also analyzed to determine whether the balanced translocations were de novo or inherited. Results: Among 32,070 cases with prenatal cytogenetic analysis, 27 cases (1/1,188 incidence) with de novo balanced translocations were identified. Fourteen cases (51.9%) showed abnormal findings, and the frequency of major structural anomalies was 11.1%. Excluding the major structural anomalies, all mothers who continued pregnancies delivered healthy babies. Conclusion: Results of a detailed, high-resolution ultrasound examination are very important in genetic counseling for prenatally diagnosed de novo balanced translocations.