• Journal of Genetic Medicine
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• 제2권2호
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• pp.59-63
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• 1998

Between 1988-1998, cytogenetic analyses were performed for 1,476 couples and 162 women with recurrent abortions. We applied GTG-banding, high resolution-banding and FISH (fluorescent in situ hybridization) techniques in this study. The frequency of balanced translocations was 3.6% (112/3114). Of them, 74 cases (2.38%) were reciprocal translocations and 38 (1.22%) were robertsonian translocations. Chromosome aberrations were more frequent in women (80 cases) than in men (32 cases). No phenotypical abnormalities were found in all carriers who had experienced recurrent spontaneous abortions or experienced giving birth to malformed offsprings. Prenatal cytogenetic analyses were carried out on 40 subsequent pregnancies for carrier couples with balanced translocation. The fetal karyotypes showed that 13 cases (32.5%) were normal, 25 (62.5%) were balanced translocations, and two (6%) were unbalanced translocations. It is believed that the frequency of chromosomal abnormalities in patients with recurrent spontaneous abortion is higher than that of the normal population. Most of the fetal samples showed normal karyotypes or balanced translocations matching that of one of their parents. Although the incidence of chromosomal imbalance in the fetuses was relatively low in prenatal cytogenetic analysis, individuals with balanced translocations are predisposed to giving birth to malformed offsprings with partial trisomy or monosomy. Therefore, we recommend the cytogenetic and the prenatal cytogenetic analysis for those who experiences recurrent abortion as well as in case they become pregnant, to prevent the birth of offsprings with chromosomal abnormalities.

• Journal of Genetic Medicine
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• 제15권1호
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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.

• Journal of Genetic Medicine
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• 제7권1호
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• pp.59-66
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• 2010

목 적: QF-PCR법은 흔한 염색체 이수성에 대한 빠른 산전 진단을 가능하게 하는데, 낮은 가격, 빠른 속도, 그리고 자동화가 가능하여 한꺼번에 많은 검체에 대해 적용할 수 있다는 장점들이 있다. 하지만 아직까지 국내에서 QF-PCR법은 산전 염색체 이수성 선별검사로 주로 사용되는 방법이 아니다. 본 연구에서는 한국인에서 빠른 산전 진단을 목적으로 시행하는 짧은 염기서열 반복(short tandem repeats, STR) 표지자를 이용한 QF-PCR법의 수행능을 검증하고자 한다. 대상 및 방법: 2007년에서 2009년까지 산전 염색체 이수성 선별을 목적으로 의뢰된 847개의 양수 검체에 대해 QF-PCR법을 시행하였는데 13번, 18번, 21번, X, Y염색체에 위치한 총 20개의 STR 표지자로 구성된 Elucigene kit (Gen-Probe, Abingdon, UK)를 사용하였다. 총 847개의 양수 검체에 대한QF-PCR 결과는 염색체 검사 결과와 비교하였고, STR 표지자의 정보력을 평가하기 위해서 각 표지자에 대해 이형접합체 지수(heterozygosity index)를 구하였다. 결 과: 총 847개 양수 검체에 대한 QF-PCR 검사 결과 19개(2.2%, 19/847)에서 13, 18, 21번 염색체와 X, Y염색체의 수적 이상이 관찰되었는데 염색체 검사에서도 동일한 결과를 보여100% 양성 예측율을 나타냈다. 하지만 염색체 검사 결과 7개(0.8%, 7/847) 검체에서 5개의 균형전좌와 2개의 불균형 염색체 이상이 관찰되었으나 QF-PCR에서는 진단되지 않았다. STR 표지자의 평균 이형접합체 지수(he-terozygosity index)는 0.76으로 서양인에서 보고된 0.8에 비해 다소 낮았다. 본 연구에서 D13S634표지자의 미세수준의 중복(submicroscopic duplication)이 1.4% (12/847)에서 관찰되었는데 이는 한국인에서 특징적인 소견으로 생각된다. 결 론: 본 기관에서는 산전 염색체 이수성 선별을 위한 QF-PCR법을 검증하였으며 효율적이고 신뢰할 수 있는 방법임이 입증되었다. 하지만 QF-PCR결과를 해석하기 위한 지침을 만들기 위해서 검사실마다 독립적으로 각각의 STR표지자에 대한 검증이 필요하며, 또한 QF-PCR법을 통상적인 염색체 검사 업무흐름에 통합하는 것이 필요하다고 사료된다.

• Journal of Genetic Medicine
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• 제10권2호
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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.

• 대한의생명과학회지
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• 제17권2호
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• pp.129-134
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• 2011

Mosaicism is the presence of two or more chromosomally distinct cell lines, each seen in two or more cells. Chromosomal mosaicism presents one of the most difficult problems in prenatal cytogenetic diagnosis, requiring the differentiation of true mosaicism from pseudomosaicism. To overcome associated problems we investigated 24 cases (amniotic fluid 13 cases, abortus tissue 3 cases, peripheral blood 8 cases) in which mosaicism has been found in cytogenetic analysis. 5 cases (38.5%) of 13 amniotic fluid cells in which mosaicisms showed single cell pseudomosaicism. Chromosomal true mosaicism is found in about 0.28% (8/2,826) of amniotic fluid cell cultures. The 24 cases involved 12 cases (50%) with sex chromosomal abnormalities, 7 cases (29.2%) with autosomal structural defects, 3 cases (12.5%) with autosomal abnormalities, 2 cases (8.3%) with a supernumerary marker. Mosaicism detected in amniotic fluid may represent the true mosaicism or may pseudomosaicism. If the same chromosome abnormality is seen in more than one cell and in two different cultures, it is considered a true mosaicism, whereas single-cell abnormalities from a single culture are regarded as pseudomosaicism. In this study, we describe a mosaicism in chromosome analysis, its diagnostic problems and clinical significance.

• Journal of Genetic Medicine
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• 제8권2호
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• pp.135-138
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• 2011

초산인 35세 산모가 고령 임신과 모체혈액선별검사 고위험군을 주소로 양수천자를 실시한 결과 8번 염색체의 단완에 위성체가 붙어 있는 것이 발견되었다. 부모 염색체 검사 결과 모두 정상으로 확인되어 태아에게서 관찰된 8ps현상은 de novo로 판단된다. FISH 검사로 좀 더 자세히 분석한 결과, 8번 염색체와 22번 염색체 사이에 미세한 전좌가 관찰되었다. 태아의 염색체 8번과 22번 사이의 de novo 전좌를 갖고 있었지만 절단 부위가 DNA의 단순 반복 부위이므로 표현형에 영향을 미칠 가능성은 높지 않을 것으로 추측되었고, 임신 기간 동안 초음파상 이상 소견은 관찰되지 않았다. 유전 상담을 통해 8번 염색체 단완의 미세 결실 가능성이 설명되었고, 부모의 결정에 따라 추가실험 없이 임신은 유지되었다. 그리고 38주에 정상 표현형의 남아가 분만되었다. 본 증례는 산전 진단에서 세포유전학적 검사로 8번 염색체 단완의 위성체만이 발견되었으나, 추가의 분자세포유전학적 진단으로 8번과 22번 염색체 단완 사이의 미세한 전좌를 확인하였다. 이처럼보다 정확하고 자세한 분자세포 유전학적 분석들이 산전 진단에서는 필요함을 시사한 사례였다.

• Journal of Genetic Medicine
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• 제4권1호
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• pp.64-71
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• 2007

목 적 : 다운증후군과 에드워드증후군의 빠른 진단에 있어 FISH 검사의 임상적 유용성과 한계성을 보고하고자 한다. 방 법 : 유전질환이 의심되는 고위험임신 309예에서 양수 검사를 통해 미배양 양수세포에서 18번과 21번 염색체의 probes를 이용한 FISH 검사를 시행하고 이들의 결과를 염색체 핵형분석 결과와 비교하였다. 결 과 : 평균연령은 34.18세, 평균임신주수는 18주(126.12 일)의 309예에서 FISH 검사는 모두 성공하였다. 각각 1예씩의 다운증후군과 에드워드증후군이 FISH로 신속한 진단이 가능했으며 이들은 염색체 핵형 검사에서 확인하였다. 그러나 18번과 21번 이외의 염색체의 이수성과 구조적 이상은 발견하지 못했는데 모두 12예(3.9%)로 상당부분을 차지했다. 앞으로 산전 선별검사에 있어 FISH검사과정의 자동화 기계화로 더 시간을 단축하고 가격을 낮추는 방안이 계속 개발되어야 할 것이다.

• Clinical and Experimental Reproductive Medicine
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• 제32권2호
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• pp.113-119
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• 2005

Objective: The purposes of this study were to investigate the types and the incidences of chromosomal abnormalities, and to provide an explanation for the genetic causations of recurrent spontaneous abortions in Korean population. Methods: Cytogenetic studies were carried out in 535 couples with at least two spontaneous first trimester abortions from January 1981 to December 2003. For karyotype analysis, we used modified Moorhead method by Giemsa staining and Giemsa-Trypsin-Giemsa banding Results: The overall incidence of chromosome abnormality was 32 out of 535 cases (5.98%). There were 25 cases (4.67%) of translocation and 7 cases (1.31%) of inversion. In translocation, 5 cases (0.93%) of Robertsonian translocation and 20 cases (3.74%) of reciprocal translocation were observed. In inversion, 6 cases (1.12%) of inversion of chromosome 9 and one case (0.19%) of inversion of chromosome 18 were found. Conclusion: In this study, overall chromosomal abnormality rate in couples with recurrent spontaneous abortions is much higher than that in the general population. So, chromosomal analysis should be offered for the prognostic information in genetic counseling such as prenatal diagnosis in couples with repetitive reproductive failure.

• Journal of Genetic Medicine
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• 제2권2호
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• pp.71-77
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• 1998

Comparative genomic hybridization (CGH) can now be applied to detect the origin of extra or missing chromosomal material in cases with common unbalanced aberrations and in prenatal investigations. This method has been used in 13 cases of fetal samples for this study; 3 for amniocytes, 2 for cord blood and 8 for abortus tissues. These samples were previously subjected to GTG-banding. Our study showed aneuploidy in 8 cases, and partial monosomy, partial trisomy or marker chromosome in the remaining 5. The CGH disclosed further small genetic imbalances in 4 of all 13 cases: a prenatal sample showing del(20)(q13) by GTG confirmed a loss of the segment 20p13-pter by CGH; a marker chromosome manifested normal CGH profile; chromosome der(?)(?;15) found in an abortus sample by GTG turned out to be a loss of 15pter-q14 (partial monosomy) and a gain of 10pter-q22 (partial trisomy); the der(15) shown by GTG represented partial trisomy of 3q24-qter. These findings show that CGH is very useful and efficient for cytogenetic investigations of clinical cases.

• Journal of Genetic Medicine
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• 제11권1호
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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.