Prenatal diagnosis of pseudomosaicism for trisomy 20 at amniocentesis with a negative non-invasive prenatal testing (NIPT) result in a pregnancy with a favorable outcome.

OBJECTIVE: We present prenatal diagnosis of pseudomosaicism for trisomy 20 at amniocentesis with a negative non-invasive prenatal testing (NIPT) result in a pregnancy with a favorable outcome. CASE REPORT: A 33-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation, which revealed a karyotype of 47,XX,+20[8]/46,XX[31]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed the result of arr (1-22,X) × 2, consistent with no genomic imbalance. She was referred to the hospital for repeat amniocentesis at 23 weeks of gestation. At repeat amniocentesis, cultured amniocytes had a karyotype of 47,XX,+20[2]/46,XX[33]. The parental karyotypes were normal. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes using SurePrint G3 Unrestricted CGH ISCA v2, 8 × 60 K (Agilent Technologies, Santa Clara, CA, USA) revealed no genomic imbalance, or arr (1-22,X) × 2, Y × 0. Interphase fluorescence in situ hybridization (FISH) analysis using the bacterial artificial chromosome (BAC) probes of RP11-266K16 [20q13.33; fluorescein isothiocyanate (FITC), spectrum green] and RP11-348I14 (20q11.1-q11.21; Texas Red, spectrum red) detected trisomy 20 signals in 4/104 uncultured amniocytes (3.8%), compared with 0/100 in the normal control. Polymorphic DNA marker analysis using the DNA extracted from uncultured amniocytes and parental bloods excluded uniparental disomy 20. NIPT analysis on maternal blood revealed a negative result without gene dosage increase in chromosome 20. The pregnancy was carried to term, and a healthy 2830-g female baby was delivered with no phenotypic abnormality. Both cord blood and placenta had a karyotype of 46,XX. CONCLUSION: NIPT is useful for rapid differential diagnosis of pseudomosaicism from true mosaicism in case of mosaic trisomy 20 at amniocentesis.

Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic 46,XX,dup(9)(q22.3q34.1)/46,XX at amniocentesis in a pregnancy with a favorable outcome.

OBJECTIVE: We present our observation of cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic dup(9)(q22.3q34.1) at amniocentesis in a pregnancy with a favorable outcome. CASE REPORT: A 37-year-old, gravida 4, para 0, woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XX, dup(9)(q22.3q34.1)[8]/46,XX[16]. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling, and repeat amniocentesis was performed at 21 weeks of gestation, which revealed a karyotype of 46,XX,dup(9)(q22.3q34.1)[7]/46,XX[25]. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed no genomic imbalance, or arr (1-22,X) × 2. Interphase fluorescence in situ hybridization (FISH) analysis on 105 uncultured amniocytes detected only one cell with the dup 9q signal with a mosaic dup 9q level of 1%, compared with 0% in normal control. At 37 weeks of gestation, a 2640-g female baby was delivered with no phenotypic abnormality. The cord blood had a karyotype of 46,XX,dup(9) (q22.3q34.1)[4]/46,XX[36], the umbilical cord had a karyotype of 46,XX,dup(9) (q22.3q34.1)[2]/46,XX[38], and the placenta had a karyotype of 46,XX. aCGH analysis on cord blood revealed no genomic imbalance. At age 2½ months, the baby was doing well, the peripheral blood of the baby had a karyotype of 46,XX,dup(9) (q22.3q34.1)[4]/46,XX[36], and interphase FISH analysis on buccal mucosal cells revealed no dup 9q signal in 100 buccal mucosal cells. CONCLUSION: Cytogenetic discrepancy may occur between cultured amniocytes and uncultured amniocytes in mosaic dup(9) (q22.3q34.1). Molecular cytogenetic analysis on uncultured amniocytes is useful for rapid distinguishing pseudomosaicism from true mosaicism under such a circumstance.

Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic trisomy 20 at amniocentesis in a pregnancy with a favorable outcome.

OBJECTIVE: We present our observation of cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic trisomy 20 at amniocentesis in a pregnancy with a favorable outcome. CASE REPORT: A 35-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XX,+20[10]/46,XX[15]. Among 25 colonies of cultured amniocytes, 10 colonies had a karyotype of 47,XX,+20, while the rest were normal. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed no genomic imbalance, or arr (1-22,X) × 2. The parental karyotypes were normal. Following genetic counseling, the woman underwent repeat amniocentesis at 20 weeks of gestation. Repeat amniocentesis revealed a karyotype of 47,XX,+20[3]/46,XX[35]. Among 38 colonies of cultured amniocytes, three colonies had a karyotype of 47,XX,+20, while the rest were normal. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed no genomic imbalance, or arr (1-22,X) × 2. Interphase fluorescence in situ hybridization analysis on 101 uncultured amniocytes detected only one cell with three chromosome 20 signals with a mosaic trisomy 20 level of 1% (1/101 cells), compared with 0% in normal control. Polymorphic DNA marker analysis on the DNA extracted from uncultured amniocytes and parental bloods excluded uniparental disomy 20. At 38 weeks of gestation, a phenotypically normal 3120-g female baby was delivered. Cytogenetic analysis of cord blood, placental tissue and umbilical cord revealed a karyotype of 46,XX. The neonate was normal at postnatal follow-ups. Postnatal interphase fluorescence in situ hybridization analysis on 100 buccal mucosal cells revealed no trisomy 20 signals. CONCLUSION: Mosaic trisomy 20 at amniocentesis can be a cultured artifact. Complete cytogenetic discrepancy may occur between cultured amniocytes and uncultured amniocytes in mosaic trisomy 20 at amniocentesis, and molecular cytogenetic analysis on uncultured amniocytes is useful for rapid distinguishing true mosaicism from pseudomosaicism under such as circumstance.

Comparison of chromosomal instability of human amniocytes in primary and long-term cultures in AmnioMAX II and DMEM media: A cross-sectional study.

BACKGROUND: The genomic stability of stem cells to be used in cell therapy and other clinical applications is absolutely critical. In this regard, the relationship between in vitro expansion and the chromosomal instability (CIN), especially in human amniotic fluid cells (hAFCs) has not yet been completely elucidated. OBJECTIVE: To investigate the CIN of hAFCs in primary and long-term cultures and two different culture mediums. MATERIALS AND METHODS: After completing prenatal genetic diagnoses (PND) using karyotype technique and chromosomal analysis, a total of 15 samples of hAFCs from 650 samples were randomly selected and cultured in two different mediums as AmnioMAX II and DMEM. Then, proliferative cells were fixed on the slide to be used in standard chromosome G-banding analysis. Also, the senescent cells were screened for aneuploidy considering 8 chromosomes by FISH technique using two probe sets including PID I (X-13-18-21) & PID II (Y-15-16-22). RESULTS: Karyotype and interphase fluorescence in situ hybridization (iFISH) results from 650 patients who were referred for prenatal genetic diagnosis showed that only 6 out of them had culture- derived CIN as polyploidy, including mosaic diploid-triploid and diploid-tetraploid. Moreover, the investigation of aneuploidies in senesced hAFCs demonstrated the rate of total chromosomal abnormalities as 4.3% and 9.9% in AmnioMAX- and DMEM-cultured hAFCs, respectively. CONCLUSION: hAFCs showed a low rate of CIN in two AmnioMAX II and DMEM mediums and also in the proliferative and senescent phases. Therefore, they could be considered as an attractive stem cell source with therapeutic potential in regenerative medicine.

Partial Hydatidiform Mole and Coexistent Live Fetus: A Case Report and Review of the Literature.

Twin pregnancy of a hydatidiform mole with a coexistent live fetus is very rare, and complete molar pregnancy is involved in most cases. A partial molar pregnancy almost always ends in miscarriage due to a triploid fetus. Here, we report a case of a 32-year-old Chinese woman with ultrasound diagnosis of a partial molar pregnancy. Amniocentesis suggested mosaicism, but the fetus was morphologically normal. The woman chose to continue the pregnancy after fully understanding the risk. The infant was delivered prematurely, and the presence of a large single placenta with molar changes. The baby's peripheral blood chromosomes were diploid, and the pregnant woman had no serious complications. The diagnosis, management, and monitoring of this condition will remain challenging because of its rarity. Partial hydatidiform mole combined with pregnancy can result in delivering of a normal fetus and live birth under proper management.

Integrated FISH, Karyotyping and aCGH Analyses for Effective Prenatal Diagnosis of Common Aneuploidies and Other Cytogenomic Abnormalities.

Current prenatal genetic evaluation showed a significantly increase in non-invasive screening and the reduction of invasive diagnostic procedures. To evaluate the diagnostic efficacy on detecting common aneuploidies, structural chromosomal rearrangements, and pathogenic copy number variants (pCNV), we performed a retrospective analysis on a case series initially analyzed by aneuvysion fluorescence in situ hybridization (FISH) and karyotyping then followed by array comparative genomic hybridization (aCGH). Of the 386 cases retrieved from the past decade, common aneuploidies were detected in 137 cases (35.5%), other chromosomal structural rearrangements were detected in four cases (1%), and pCNV were detected in five cases (1.3%). The relative frequencies for common aneuploidies suggested an under detection of sex chromosome aneuploidies. Approximately 9.5% of cases with common aneuploidies showed a mosaic pattern. Inconsistent results between FISH and karyotyping were noted in cases with pseudo-mosaicism introduced by culture artifact or variable cellular proliferation from cells with mosaic karyotypic complements under in vitro cell culture. Based on findings from this case series, cell-based FISH and karyotyping should be performed to detect common aneuploidies, structural chromosomal abnormalities, and mosaic pattern. DNA-based aCGH and reflex FISH should be performed to detect and confirm genomic imbalances and pCNV. Practice points to ensure the diagnostic accuracy and efficacy were summarized.

Rapid diagnosis of pseudomosaicism in a case of Level II mosaicism for trisomy 5 in a single colony from an in situ culture of amniocytes and a review of mosaic trisomy 5 at amniocentesis.

OBJECTIVE: We present prenatal diagnosis of pseudomosaicism for trisomy 5 and a review of the literature of mosaic trisomy 5 at amniocentesis. CASE REPORT: A 39-year-old woman underwent amniocentesis at 17 weeks of gestation, which revealed a karyotype of 47,XY,+5[1]/46,XY[20]. The single colony with trisomy 5 had five metaphase cells, and all five cells had the karyotype of 47,XY,+5. Repeat amniocentesis performed at 20 weeks of gestation revealed a karyotype of 46,XY in 27/27 colonies. Simultaneously, interphase fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH), and quantitative fluorescent polymerase chain reaction (QF-PCR) were performed on uncultured amniocytes. Interphase FISH revealed no trisomy 5 in 100 uncultured amniocytes. aCGH revealed no genomic imbalance. QF-PCR excluded uniparental disomy 5. A healthy 3662-g male baby was delivered with a normal karyotype in cord blood and 3.75% (3/80 cells) of trisomy 5 cells in uncultured urinary cells compared with 0.95% (1/105 cells) of trisomy 5 cells in normal control examined by FISH at 1.5 months of age. A review of seven cases with mosaic trisomy 5 at amniocentesis shows that 4/7 had clinically normal outcome, 3/7 had structural defects, mainly the heart, 6/6 had normal karyotype in blood, and 2/3 had mosaic trisomy 5 in the fetal tissues. CONCLUSION: Prenatal diagnosis of mosaic trisomy 5 should alert the possibility of fetal structural abnormalities, especially the heart, and culture artifacts. We suggest that the application of molecular cytogenetic techniques such as aCGH, interphase FISH, and QF-PCR on uncultured amniocytes is useful in our understanding of the mosaic status at repeat amniocentesis.

Six-years' Experience of Pseudomosaicism and Maternal Cell Contamination in Cultured Amniocytes

PURPOSE : To present our experiences in pseudomosaicism or maternal celi contamination in genetic mid-trimester amniocentesis confirmed through percuraneous umbilical blood sampling. METHODS : From 1992 to 1997, repeated cytogenetic evaluation with fetal cord blood was carried out in 14 cases showing mosaic patterns. RESULTS : We confirmed pseudomosaicsm in 12 cases (85.7%) by repeated cytohenetic evaluation, and also maternal cell contamination in 2 cases. CONCLUSIONS : Repeated cytohenetic evaluation via percutaneous umbilical blood sampling was a rapid and useful method fof the confirmation of mosaicism resulted from genetic mid-trimester amnicentesis.