• Biomedical Science Letters
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• v.17 no.2
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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.

• Development and Reproduction
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• v.22 no.2
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• pp.199-203
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• 2018

Although trisomy 16 is commonly detected in spontaneous abortions and accounts for over 30% of cases of autosomal trisomy detected after spontaneous abortion, trisomy 16 mosaicism is rarely detected by amniocentesis in the second trimester. Here, we report a case of level III trisomy 16 mosaicism (47,XX,+16[8]/46,XX[31]) diagnosed by cytogenetic analysis of independently cultured amniotic fluid cells. The female baby was delivered at full term with low birth weight and intrauterine growth retardation, and interestingly, her karyotype was normal (46,XX). Given the difficulty in predicting the outcomes of fetuses with this mosaicism, it is recommended to inform the possibility of mosaicisms including this trisomy 16 mosaicism during prenatal genetic diagnosis and genetic counseling for parents.

• Journal of Genetic Medicine
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• v.3 no.1
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• pp.21-24
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• 1999

To study the X chromesome mosaicism in the cytogenetically pure 45,X Turner syndrome patients, we applied PCR technique using DNAs extracted from archived cytogenetic slides. We amplified the DNAs using nested primers targeted to a highly polymorphic short tandem repeat(STR) of the human androgen receptor gene(HUMARA) for the detection of X chromosome mosaicism. This assay is a very sensitive and useful method which can be applied to the DNAs extracted from archived cytogenetic slides to detect X mosaicism. We have tested 50 normal Korean females to determine whether the HUMARA locus is highly polymorphic among Koreans. 85% of Korean population showed heterozygosity in the HUMARA locus. We analysed the 24 DNAs extracted from archived slides of patients and abortuses with Turner syndrome in cytogenetic analysis. We observed the heterozygosities of 50% from pure 45,X patients, 83% from the patients with mosaic Turner syndrome and 8.3% from the abortuses of pure 45,X. Using the PCR technique of the HUMARA locus in the archived cytogenetic slides, we detected X chromosome mosaicism which could not be detected in cytogenetic analysis.

• Clinical and Experimental Pediatrics
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• v.55 no.10
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• pp.393-396
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• 2012

Trisomy 14 mosaicism is a rare chromosome disorder characterized by delayed development, failure to thrive, and facial dysmorphism. Only approximately 30 trisomy 14 mosaicism cases have been reported in the literature because trisomy 14 is associated with early spontaneous abortion. We report a case of a 17-month-old girl with abnormal skin pigmentation, delayed development, facial dysmorphism, and failure to thrive with the 47,XX,+14/46,XX chromosome complement.

• Journal of Genetic Medicine
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• v.10 no.1
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• pp.52-56
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• 2013

Mosaic trisomy 14 syndrome is a well-known but unusual chromosomal abnormality with a distinct and recognizable phenotype. Array comparative genomic hybridization (CGH) analysis has recently become a widely used method for detecting DNA copy number changes, in place of traditional karyotype analysis. However, the array CGH shows a limitation for detecting the low-level mosaicism. Here, we report the detailed clinical and cytogenetic findings of patient with low-frequency mosaic trisomy 14, initially considered normal based on usual cut-off levels of array CGH, but confirmed by G-banding karyotyping. Our patient had global developmental delay, short stature, congenital heart disease, craniofacial dysmorphic features, and dark skin patches over her whole body. Estimated mosaicism proportion was 23.3% by G-banding karyotyping and 18.0% by array CGH.

• Journal of Genetic Medicine
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• v.10 no.2
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• pp.117-119
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• 2013

Double trisomy mosaicism of two different cell lines is extremely rare, particularly those that involve constitutional trisomy 8. We report a case of 47,XXX/47,XX,+8 in a 12-year-old female presenting with several skeletal anomalies. She exhibited distinct phenotypic features such as tall stature, deviation of the left middle finger, webbing of both thumbs and flexion deformities of the both third and fifth distal intermediate phalanges. A mild impulse-control disorder was observed, without mental retardation. Chromosomal and fluorescence in situ hybridization analysis demonstrated double trisomy mosaicism both on lymphocytes and buccal epithelial cells.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.95-101
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• 1992

During the years 1983 to 1991, cytogenetic analysis was performed on 19 women with Turner syndrome in order to find out the incidence of symptoms and signs according to the classification of chromosome abnormalities. 1. All of them showed short stature and the mean height in 7 adults was $140.71{\pm}5.26cm$. 2. Among the 19 patients with Turner syndrome, 7 (36.8%) had 45, XO karyotype, 7 (36.8%) had 46, Xi (Xq), and remained 5 (26.3%) had mosaicism. 3. Five patients with mosaicism had 45, X/46, XX (2), 45, X/46, Xi (Xq) (2) and 45, X/47, XXX (1), respectively. 4. Patients with 45, XO and 46, Xi (Xq) had amenorrhea, whereas only 33% (1/3) of patients with mosaicism had amenorrhea. Total incidence of amenorrhea was 84.6% (11/13). 5. Abnormal external genitalia was detected in 63.6% of patients. The incidence of abnormality in patients with mosaicism was lower than that of other groups. 6. OMPC and deafness were detected in 3 of 19 patients. 7. Two cases of cardiovascular abnormalities were found in patients with 45, XO. This study suggests that gnenetic counselling according to the classification of chromosomal abnormalities could be needed in patients with Turner syndrome.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1317-1323
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• 2005

Purpose : This study was performed to evaluate the recent frequency of karyotypes in different sex chromosome abnormalities and to evaluate the age and clinical manifestations at diagnosis. Methods : Peripheral blood leukocytes were obtained from subjects who were clinically suspected to have sex chromosome abnormalities and referred to the cytogenetic laboratory in the Department of Pediatrics, Kyungpook National University Hospital from February 1981 to August 2001. Results : The relative frequencies of different sex chromosome abnormalities were Klinefelter(52 percent), Turner(42 percent), XXX syndrome(3 percent) and mixed gonadal dysgenesis(3 percent). The populations of different karyotypes in Klinefelter syndrome were 47,XXY(97 percent) and 46,XY/47,XYY(3 percent). The populations of different karyotypes in Turner syndrome were 45,X(67 percent,), mosaicism(23 percent), and structural aberrations(10 percent). The populations of different karyotypes in XXX syndrome were 47,XXX(67 percent,) and 46,XX/47,XXX(33 percent). All mixed gonadal dysgenesis were 45,X/46,XY. Eighty one percent of sex chromosome abnormalities was diagnosed after puberty. Patients diagnosed with Klinefelter and Turner syndrome in infancy showed nearly normal phenotypes or had minor congenital malformations. Conclusion : Early diagnoses of sex chromosome abnormalities is required to prevent associated morbidities and to maximize growth and development. We have to pay careful attention in diagnoses of Turner syndrome because of the high proportion of mosaicism and structural aberrations.

• Clinical and Experimental Pediatrics
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• v.46 no.4
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• pp.397-399
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• 2003

All complete monosomy 21 appear to be lethal early in their development in humans and only survive in mosaic forms. Complete monosomy 21 is a very rare and usually debilitating genetic disorder. Partial monosomy 21 is also rare and is thought to constitute a clinical syndrome consisting of peculiar faces, hypertonia, psychomotor retardation, and slow growth. We experienced a case of monosomy 21 mosaicism. Chromosome analysis demonstrated mosaicism for cell lines in the lymphocytes examined; 45, XX, -21/46, XX. The main clinical features were craniofacial dysmorphism including high arched palate, submucosal cleft, micrognathia and arthrogryposis-like symptoms including flexion deformity of fingers. And hematological findings were revealed dyserythropoiesis, thrombocytopenia and eosinophilia. Currently, the patient has nearly compatible growth, but a mild degree of mental retardation. We report here an 8 years old female child with apparent monosomy 21 mosaicism associated with dyserythropoiesis, thrombocytopenia and eosinophilia, with a review of the associated literatures.

• 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.