• 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.

• 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.

• 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.6 no.1
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• pp.95-99
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• 2009

Prenatal diagnosis of rare autosome mosaicism involvingchromosomes other than chromosome 13, 18, 21 or the sex chromosome is encountered prognostic dilemma during genetic counseling. We report four cases of level III uncommon mosaicism of trisomy 5, 16 and 20,diagnosed prenatally. In case 1 with mosaic trisomy 20, there was a higher mosaic ratio of trisomy 20 in the repeat amniocentesis (62.1%) than in the first (36.6%) with normal fetal ultrasound finding except for a relatively small aorta on a 3-vessel view of the fetal heart. Case 2 showed a low rate of mosaic trisomy 20 (5.25%) in cultured amniocytes but normal karyotype in the repeat amniocentesis, who delivered a normal healthy baby. Case 3 showed a 13.6% of trisomy 16 mosaicism in the 30 cells of cultured amniocytes. Sixty cells from a fetal blood sample at termination showed non-mosaic 46,XX normal karyotype, while skin fibroblasts had 22.5% trisomy 16 in 40 metaphases. The autopsy showed ventricular septal defect (VSD). Case 4 with low grade mosaicism (10.5%) of trisomy 5 resulted in elective termination, though the ultrasoumd showed growsly normal fetus. Although level III mosaicism is regarded as true mosaicism, it is difficult to predict the outcome of the fetus with rare mosaic autosome trisomy. Therefore mosaic autosome trisomy of fetus should be carefully interpreted with more various approaches including repeat sampling and targeted fetal ultrasound.

• Journal of Genetic Medicine
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• v.5 no.1
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• pp.61-64
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• 2008

A 24-year-old female with primary amenorrhea was referred for a chromosome study. The karyotype of the patient was 46,X,der(X) under initial GTG-banding analysis. Fluorescence in situ hybridization (FISH) analysis with an LSI Kallmann (KAL) region probe [probes for Xp22.3(KAL) and CEP(X) for control] was carried out. The abnormal chromosome was KAL- and CEP(X)${\times}2$. In addition, interphase FISH analysis revealed the patient to be mosaic for two different cell lines: 90% of cells had three signals and 10% of the cells had only one signal for CEP(X). Based on these results, the karyotype of the patient was 45,X/46,X,psu idic(X)(p22.1), which is partial trisomy for Xqter${\rightarrow}$Xp22.1 and partial monosomy for Xpter${\rightarrow}$Xp22.1. This karyotype was considered a variant of Turner syndrome. In summary, Idic(X) and low-level mosaicism was successfully characterized by FISH analysis with a CEP(X) probe.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.111-118
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• 2010

Chromosomal microarray analysis (CMA) enables the genome-wide detection of submicroscopic chromosomal imbalances with greater precision and accuracy. In most other countries, CMA is now a commonly used clinical diagnostic test, replacing conventional cytogenetics or targeted detection such as FISH or PCR-based methods. Recently, some consensus statements have proposed utilization of CMA as a first-line test in patients with multiple congenital anomalies not specific to a well-delineated genetic syndrome, developmental delay/intellectual disability, or autism spectrum disorders. CMA can be used as an adjunct to conventional cytogenetics to identify chromosomal abnormalities observed in G-banding analysis in constitutional or acquired cases, leading to a more accurate and comprehensive assessment of chromosomal aberrations. Although CMA has distinct advantages, there are several limitations, including its inability to detect balanced chromosomal rearrangements and low-level mosaicism, its interpretation of copy number variants of uncertain clinical significance, and significantly higher costs. For these reasons, CMA is not currently a replacement for conventional cytogenetics in prenatal diagnosis. In clinical applications of CMA, knowledge and experience based on genetics and cytogenetics are required for data analysis and interpretation, and appropriate follow-up with genetic counseling is recommended.