• Journal of Genetic Medicine
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• v.12 no.2
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• pp.118-122
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• 2015

Noninvasive prenatal test (NIPT) is a novel screening method for the diagnosis of fetal chromosomal aneuploidies. NIPT is based on technology that detects cell-free fetal DNA in maternal plasma and analyzes it with massively parallel sequencing technology to determine whether the fetus is at risk of trisomy 21, trisomy 18, trisomy 13 or sex chromosome abnormalities (SCAs). NIPT has been reported to have sensitivity of 99% and a false positive rate of less than 1% for detecting trisomy 21 and trisomy 18. Although extension of the application of NIPT to other SCAs has been attempted, there are concerns in extending NIPT to SCAs because of maternal or fetal mosaicism, undetected maternal SCAs, and multiple pregnancies. Recently, we assessed a pregnancy with the rare Turner syndrome mosaicism 45, X/47, XXX, which was reported as 45, X with NIPT. We present the case here and briefly review the current literatures on NIPT in testing for fetal monosomy X. To the best of our knowledge, this is the first report of the 45, X/47, XXX mosaicism in Korea to be reported as 45, X by NIPT with whole genome sequencing. This case report will provide valuable information for counseling women who want to undergo NIPT.

• Journal of Yeungnam Medical Science
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• v.22 no.2
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• pp.241-246
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• 2005

Constitutional trisomy 8 is a relatively rare aneuploidy; most identified cases are mosaic with a normal cell line. The phenotype is highly variable from apparently normal to severe disability. The proportion of abnormal cells is dramatically different between tissues and the severity of the phenotype is not directly related to the level of mosaicism. Therefore, it is very difficult to provide a definitive prognosis. We report here a case of constitutional trisomy 8 mosaicism with agenesis of the corpus callosum, congenital heart disease and micrognathia. The trisomy 8 cell line was not detected by prenatal cytogenetic study. This is the fourth reported case of constitutional trisomy 8 mosaicism in Korea.

• Journal of Genetic Medicine
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• v.14 no.1
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• pp.31-33
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• 2017

Chromosomal loss in trisomy (trisomy rescue) to generate a disomic fetus can cause confined placental mosaicism and/or feto/placental mosaicism. After trisomy rescue event, there is a risk of fetal uniparental disomy (UPD). Noninvasive prenatal test (NIPT) reflects the genomic constitution of the placenta, not of the fetus itself. Feto-placental discrepancy can therefore cause false-positive (trisomy) NIPT results. These discordant NIPT results can serve as important clues to find UPD associated with confined placental mosaicism. We report a case with maternal UPD of chromosome 20, detected by NIPT of 1,000 high-risk pregnancies, carried out for detecting chromosomal abnormalities in Koreans.

• Childhood Kidney Diseases
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• v.1 no.2
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• pp.151-154
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• 1997

Purpose : The prevalence of renal malformation in Turner syndrome has been quoted as being greater than 50% in older series. Recently in 1988, Lippe's review gave a prevalence of 33%, significantly lower than all previous reports. In 1996, Flynn reported that renal malformation occurs in approximately 24% of all girls with Turner syndrome, and that it is seldom seen in girls with mosaic karyotype who form the predominant subgroup. The aim of this study was to evaluate prevalence of renal malformation by karyotype in Turner syndrome in Korea. Method : We evaluated 81 patients with Turner sundrome diagnosed in Yonsei University from Jan. 1987 to Dec. 1996. The patient entered in this study were those for whom both karyotype and ultrasound examination of the kidney were available. Result : 1) The karyotype showed: 45,X ; 29 cases (38%), mosaicism : 32 cases (40%), structural aberration ; 17 cases (22%). 2) Of the 29 cases of pure 45,X karyotype, 5(17%) had abnormal renal findings, while these were found in only 1 of the 30 mosaic cases(3.3%), and in 1 of the 17 structural aberration cases(6%). The malformation included 3 cases of horseshoe kidney, 2 cases of axial malrotation, hypoplastic kidney and simple cyst each one. There was no statistical significance between 3 groups (p=0.09). Conclusion : We conclude that renal malformation occurs in 9.2% in this study, therefore Korean girls with Turner syndrome have lower rates of renal malformation.

• 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.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.597-601
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• 2003

Trisomy 9 mosaic syndrome is a rarely reported chromosomal abnormality with high incidence of intrauterine growth retardation and perinatal death. Even a baby lives, he has severe mental retardation and significant malformations. The incidence and severity of malformations and mental retardation correlate with the percentage of trisomic cells in the different tissues. The characteristic craniofacial abnormalitis are narrow bifrontal diameter, up-slanted and short palpebral fissures, a prominent nasal bridge with a short root, a prominent lip covering a receding lower lip, low-set, posteriorly rotated, and misshapen ears. Ventricular septal defect is a main cardiac abnormality. Bony hypoplasia and dislocated hips have been frequently reported. Central nervous system, hepatobiliary, gastrointestinal and genitourinary abnormalities also had been reported. The authors report a baby who had characteristic abnormalities of trisomy 9 mosaicism with narrow temples, up-slanted palpebral fissures, a bulbous nose, thin and protruding upper lip, low set and malformed ears, hyperextended wrist and overlapping fingers. Cytogenetic analysis performed to confirm the chromosomal abnormality revealed trisomy 9, low level mosaic type.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.67-70
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• 2011

Constitutional trisomy 8 mosaicism (CT8M) is a relatively rare aneuploidy in humans with characteristic phenotypes including typical craniofacial feature (such as deformed skull, prominent forehead, low-set and/or dysplastic ears), skeletal malformation, cardiac anomaly, renal malformation, cryptochidism, varying degree of developemental delay. Due to the extremely variable phenotypic and cytogenetic expression, CT8M has gone undiagnosed in certain patients. We report a 28-year-old women with secondary amenorreha without characteristic CT8M phenotype. Chromosomal analysis showed a CT8M (47,XX,+8[9]/46,XX[41]).

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.457-465
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• 1999

Objective: The presence of Y chromosome in patients with gonadal dysgenesis is related to the risk of gonadoblastoma. Since the patients with abnormal sexual differentiation may have cryptic Y mosaicism, it is important to detect the presence of Y material in these patients. But sometimes it is difficult to detect Y material only with karyotyping. This study was performed to evaluate the usefulness of the SRY gene screening in blood and gonad by using PCR in detecting the presence of Y material and possible tissue mosaicism in patients with gonadal dysgenesis as Turner syndrome and 46,XY pure gonadal dysgenesis (PGD, Swyer syndrome). Method: In 26 patients with gonadal dysgenesis, we screened for Y material by using PCR for SRY gene in peripheral leukocytes and in gonadal tissues of some patients. They were 22 cases of Turner syndrome (7 45,XO, 2 46,Xi(Xq), 3 45,XO/46,XX, 5 45,XO/46,Xi(Xq), 1 45, XO/46,XY, 1 45,XO/46,Xi(Yq), 1 45,XO/47,XYY, 1 46,XX,del(X)(q24) and 1 46,X,+mar) and 4 cases of 46,XY pure gonadal dysgenesis. PCR for SRY gene in the gonadal tissue was performed in 5 Turner syndrome and 2 PGD to determine the cryptic Y mosaicism between blood and gonad. Results: By using PCR analysis for SRY, Y chromosome material was detected in the blood of 4 of 22 Turner syndrome patients (45,XO/46,Xi(Xq), 45,XO/46,Xi(Yq), 45,XO/46,XY, and 45, XO/47,XYY), 3 of 4 46,XY pure gonadal dysgenesis. Discrepancy between karyotyping and blood PCR for SRY was noted in 1 Turner syndrome (45,XO/46,Xi(Xq)) and 1 PGD. Laparoscopic gonadectomy was performed in Y containing or SRY positive cases. In addition, PCR analysis for SRY in the gonads of 5 Turner syndrome and 2 PGD showed discrepancy between blood and gonad or between both gonads in 3 Turner syndrome (45,XO/46,Xi(Xq), 45,XO/46,Xi(Y q), 45,XO/46,XY) and 2 PGD patients. Conclusion: In gonadal dysgenesis, PCR analysis for SRY gene is useful to detect the cryptic Y mosaicism that is sometimes undetected by karyotyping. And since there may be tissue mosaicism, it is necessary to evaluate Y mosaicism in various tissues even in the case without Y chromosome on karyotyping.

• Journal of Genetic Medicine
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• v.2 no.1
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• pp.7-10
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• 1998

The present report describes a case that showed a normal fetal karyotype in an antenatal genetic study but an abnormal placental karyotype of 46,XX,r (15) on postnatal examination. The pregnancy was complicated by fetal nuchal translucency in the first trimester and intrauterine growth restriction in the second and third trimesters. A 1780 gm female baby was born after 40 weeks of gestation, but died of respiratory distress and sepsis on the 10th day of life. Our case was unique in that the placental chromosomal aberration was a structural abnormality instead of a numerical aberration that is seen in most reported cases of confined placental mosaicism.

• Journal of Genetic Medicine
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• v.17 no.1
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• pp.47-50
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• 2020

In Turner syndrome (TS), 45,X/47,XXX mosaicism is a rare genotype. Due to its low frequency, the clinical features and prognosis are not clearly known. A 10-year-old girl was diagnosed with 45,X/47,XXX mosaicism TS and presented with short stature. She did not show any other TS phenotypic features, except for short stature, and developed spontaneous puberty and menarche, although she had unilateral ovarian agenesis. She achieved a significant growth improvement following growth hormone treatment. Since 45,X/47,XXX mosaic TS shows different gonadal function from that of classic TS, it is necessary to conduct surveillance for premature ovarian insufficiency.