Prenatal diagnosis and molecular cytogenetic characterization of de novo partial monosomy 3p (3p26.3→pter) and partial trisomy 16q (16q23.1→qter)

AbstractObjectiveTo present the prenatal diagnosis and molecular cytogenetic characterization of a de novo unbalanced reciprocal translocation.Case ReportA 37-year-old woman, G3P1, underwent amniocentesis at 17 weeks of gestation because of her advanced maternal age. Her husband was 38 years old. Amniocentesis revealed a derivative chromosome 3 with the deletion of terminal 3p and the addendum of an unknown extra chromosomal segment on the distal 3p. The parental karyotypes were normal. Prenatal ultrasound findings were unremarkable. Array comparative genomic hybridization (aCGH) analysis using cultured amniocytes revealed a 2.38-Mb deletion in 3p26.3 [arr 3p26.3 (1-2,380,760)×1] encompassing 15 genes, which included 3 OMIM genes CHL1, CNTN6, and CNTN4, and a 13.17-Mb duplication in 16q23.1-q24.3 [arr 16q23.1q24.3 (76,999,082-90,170,596)×3] encompassing 207 genes, which included 81 OMIM genes. The pregnancy was subsequently terminated, and a malformed fetus was delivered with facial dysmorphism. Postnatal cord blood analysis revealed a karyotype of 46,XY,der(3)t(3;16)(p26.3;q23.1)dn. Polymorphic DNA marker analysis by quantitative fluorescent polymerase chain reaction (QF-PCR) on the DNAs extracted from the placenta and parental blood showed a paternal origin of the aberrant chromosome.ConclusionThe aCGH and QF-PCR analyses helped in delineating the genomic imbalance and parental origin of prenatally detected de novo unbalanced reciprocal translocation

Detection of no isochromosome 20q by interphase fluorescent in situ hybridization on uncultured amniocytes in a pregnancy with mosaic isochromosome 20q in cultured amniocytes at amniocentesis

AbstractObjectiveTo present prenatal diagnosis and molecular cytogenetic characterization of mosaic isochromosome 20q at amniocentesis.Materials and methodsA 36-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age, and conventional cytogenetic analysis revealed a karyotype of 46,XY,i(20)(q10)[12]/46,XY[7]. Repeated amniocentesis was performed at 20 weeks of gestation. During repeated amniocentesis, array comparative genomic hybridization (aCGH), interphase fluorescence in situ hybridization (FISH), and quantitative fluorescent polymerase chain reaction (QF-PCR) were performed on uncultured amniocytes, and conventional cytogenetic analysis and interphase FISH were performed on cultured amniocytes.ResultsConventional cytogenetic analysis of cultured amniocytes revealed a karyotype of 46,XY,i(20)(q10)[4]/46,XY[16]. Interphase FISH analysis on 217 uncultured amniocytes did not detect isochromosome 20q, aCGH on the DNA extracted from uncultured amniocytes showed no genomic imbalance, and QF-PCR analysis on the DNA extracted from uncultured amniocytes excluded uniparental disomy 20 (UPD 20). Interphase FISH analysis on 115 cultured untouched amniocytes revealed 13% (15/115 cells) mosaicism for isochromosome 20q.ConclusionMosaic isochromosome 20q detected at amniocentesis can be a cell culture artifact. Detailed ultrasound examination, performing interphase FISH and/or aCGH on uncultured amniocytes for confirmation of true mosaicism, and performing QF-PCR to exclude UPD 20 may be useful under such a circumstance

Mosaicism for a 15q11.2 microduplication with a normal euploid cell line at amniocentesis in a pregnancy with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with the microduplication

Objective: We present mosaicism for a 15q11.2 microduplication with a normal euploid cell line at amniocentesis in a pregnancy with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with the microduplication. Case report: A 35-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed 33.76% mosaicism for a 15q11.2 microduplication. She was referred for genetic counseling. Repeat amniocentesis was performed at 23 weeks of gestation, and the karyotype was 46,XY. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed the result of arr [GRCh37 (hg19)] 15q11.2 (23, 889, 686–25,514,125) × 2.45, consistent with a mosaic 1.624-Mb microduplication with the mosaic level of 40%–45% (log2 ratio = 0.28) encompassing nine OMIM genes of MAGEL2, NDN, PWRN2, PWRN1, NPAP1, SNRPN, SNHG14, SNORD116-1 and SNORD115-1. Interphase fluorescence in situ hybridization (FISH) analysis on 100 uncultured amniocytes detected a 15q11.2 duplication in 19 cells, consistent with 19% (19/100 cells) mosaic15q11.2 duplication. Polymorphic DNA marker analysis excluded uniparental disomy (UPD) 15. Prenatal ultrasound findings were unremarkable. She was advised to continue the pregnancy, and a 3865-g phenotypically normal male baby was delivered. aCGH analysis on the DNA extracted from cord blood at birth and buccal mucosal cells at age four months revealed arr (1–22) × 2, X × 1, Y × 1 and detected no genomic imbalance in all samples. Interphase FISH analysis on 104 buccal mucosal cells at age four months detected four cells (4/104 = 4%) with a 15q11.2 duplication, compared with 0% (0/102 cells) in the normal control. The neonate was normal in the development. Conclusion: Mosaicism for a 15q11.2 microduplication at amniocentesis with a normal euploid cell line can be a benign condition and associated with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with the microduplication

Mosaicism for a 12p12.1p12.2 microdeletion with a normal euploid cell line at amniocentesis in a pregnancy with a favorable outcome and postnatal decrease of the aneuploid cell line with microdeletion

Objective: We present mosaicism for a 12p12.1p12.2 microdeletion with a normal euploid cell line at amniocentesis in a pregnancy with a favorable outcome and postnatal decrease of the aneuploid cell line with microdeletion. Case report: A 35-year-old woman, gravida 2, para 1, underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed mosaic 46,XY,del (12) (p11.2p12), and array comparative genomic hybridization (aCGH) revealed arr Xp22.31 × 2 mat, 12p12.2p12.1 × 1 [0.36]dn with a 4.15-Mb 36% mosaicism for a 12p12.1p12.2 microdeletion. At 22 weeks of gestation, she underwent cord blood sampling of which aCGH revealed arr Xp22.31 × 2 mat, 12p12.2p12.1 × 1 [0.34]dn with a 4.24-Mb 34% mosaicism for a 12p12.1p12.2 microdeletion. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling, and continuing pregnancy was advised. A 2990-g male baby was delivered at 38 weeks of gestation with no phenotypic abnormality. When follow-up at age 1½ months, the neonate was phenotypically normal. The karyotype of peripheral blood was 46,XY. aCGH analysis on the DNA extracted from peripheral blood revealed the result of arr 12p12.1p12.2 (20, 367, 240–24,489,386) × 1.87, arr Xp22.31 (6,488,721–8,097,511) × 2.0 [GRCh37 (hg19)] with 10–15% (log2 ratio = 0.1) mosaicism for a 4.122-Mb 12p12.1-p12.2 microdeletion encompassing 17 OMIM genes of PDE3A, SLCO1C1, SLCO1B3, SLCO1B1, IAPP, PYROXD1, RECQL, GOLT1B, SPX, GYS2, LDHB, KCNJ8, ABCCP, CMAS, C2CD5, ETNK1 and SOX5 and a 1.609-Mb Xp22.31 duplication encompassing two OMIM genes of STS and VCX. Interphase fluorescence in situ hybridization (FISH) analysis on 104 buccal mucosal cells using 12p12.1-specific probe showed 17% (18/104 cells) mosaicism for a 12p12.1 deletion. Polymorphic DNA marker analysis on the DNA extracted from proband's blood and parental bloods determined a paternal origin of the mosaic 12p12.1 deletion. Conclusion: Mosaicism for a 12p12.1p12.2 microdeletion at amniocentesis with a normal euploid cell line can be a benign condition in association with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with microdeletion

45,X/46,XX at amniocentesis associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes and in different amniocenteses and a favorable fetal outcome with a normal karyotype at birth

Objective: We present 45,X/46,XX at amniocentesis associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes and in different amniocenteses and a favorable fetal outcome with a normal karyotype at birth. Case report: A 35-year-old, gravida 3, para 2, woman underwent amniocentesis at 20 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[11]/46,XX[108], consistent with 9.2% mosaicism for 45,X. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling at 25 weeks of gestation, and repeat amniocentesis at 26 weeks of gestation revealed a karyotype of 45,X[4]/46,XX[16], consistent with 20% mosaicism for 45,X. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes using SurePrint G3 Unrestricted CGH ISCA v2, 8 × 60K (Agilent Technologies, Santa Clara, CA, USA) revealed arr (1–22, X) × 2, Y × 0 with no genomic imbalance. The woman was advised to continue pregnancy, and at 38 weeks of gestation, a healthy 3140-g female baby was delivered with no phenotypic abnormalities. The cord blood had a karyotype of 46,XX (40/40 cells). When follow-up at age two months, the neonate had normal development and a normal karyotype. Conclusion: Confirmation of 45,X/46,XX at amniocentesis should include conventional cytogenetic analysis and karyotyping on cultured amniocytes, and sole molecular analysis on uncultured amniocytes may miss the diagnosis of 45,X/46,XX

Perinatal detection of disomy X cell line by fluorescence in situ hybridization in a pregnancy with 45,X/47,XXX at amniocentesis, cytogenetic discrepancy in various tissues and a favorable outcome

Objective: We present perinatal detection of disomy X cell line by fluorescence in situ hybridization (FISH) in a pregnancy with 45,X/47,XXX at amniocentesis, cytogenetic discrepancy in various tissues and a favorable outcome. Case report: A 34-year-old, gravida 3, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[22]/47,XXX[10]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed the result of arr (X) × 1–2, (1–22) × 2, consistent with 32% mosaicism for monosomy X. She was referred for genetic counseling at 19 weeks of gestation. Prenatal ultrasound findings and parental karyotypes were normal. Repeat amniocentesis at 29 weeks of gestation revealed a karyotype of 45,X[36]/47,XXX[4] (Fig. 1) in cultured amniocytes. Simultaneous molecular analysis on uncultured amniocytes revealed the result of arr (1–22) × 2, Y × 0 by aCGH with no genomic imbalance, and 15% (15/100 cells) mosaicism for disomy X, 61% (61/100 cells) mosaicism for monosomy X and 24% (24/100 cells) mosaicism for triple X by interphase fluorescence in situ hybridization (FISH) analysis. The pregnancy was encouraged to continue and at 37 weeks of gestation, a 2834-g phenotypically normal female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 45,X[33]/47,XXX[7], 45,X[30]/47,XXX[10] and 47,XXX[38]/45,X[2], respectively. When follow-up at age three months, the neonate was normal in development. FISH analysis on 99 buccal mucosal cells showed 49% (48/99 cells) mosaicism for monosomy X, 8% (8/99 cells) mosaicism for triple X and 43% (42/99 cells) mosaicism for disomy X (Fig. 2). Peripheral blood had a karyotype of 45,X[38]/47,XXX[2]. When follow-up at age nine months, the neonate was normal in development. FISH analysis on 102 buccal mucosal cells showed 11% (11/102 cells) mosaicism for monosomy X, 12% (12/102 cells) mosaicism for triple X and 77% (79/102 cells) mosaicism for disomy X. Peripheral blood had a karyotype of 45,X[30]/47,XXX[10]. Conclusion: 45,X/47,XXX at amniocentesis may detect disomy X cell line by FISH analysis and can be associated with postnatal progressive decrease of the aneuploid cell lines, increase of the disomy X cell line and a favorable outcome

45,X/46,XX at the first amniocentesis, and 45,X/47,XXX/46,XX at the repeat amniocentesis and at birth in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the 45,X cell line and cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes

Objective: We present 45,X/46,XX at the first amniocentesis, and 45,X/47,XXX/46,XX at the repeat amniocentesis and at birth in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the 45,X cell line and cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes. Case report: A 43-year-old, gravida 3, para 1, woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[4]/46,XX[20]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr (X) × 3 [0.24], consistent with 24% mosaicism for triple X. Repeat amniocentesis at 20 weeks of gestation revealed the result of 45,X[17]/47,XXX[8]/46,XX[121]. She was referred for genetic counseling, and the third amniocentesis performed at 30 weeks of gestation revealed the result of 45,X[3]/47,XXX[2]/46,XX[16]. The mother had a karyotype of 46,XX. aCGH analysis on the DNA extracted from uncultured amniocytes showed arr Xp22.33q28 × 2.2 (log2 ratio = 0.15), consistent with 20% mosaicism for triple X. Interphase fluorescence in situ hybridization (FISH) analysis on 100 uncultured amniocytes showed that 11 cells (11%) were monosomy X, seven cells (7%) were triple X, and the others were disomy X. At 39 weeks of gestation, a 3,620-g phenotypically normal female baby was delivered without any phenotypic abnormality. The karyotypes of cord blood, umbilical cord and placenta were 47,XXX[7]/45,X[1]/46,XX[32], 47,XXX[13]/46,XX[27] and 47,XXX[2]/46,XX[38], respectively. When follow-up at age one month, the neonate was phenotypically normal, and FISH analysis on 106 buccal mucosal cells showed that eight cells (7.5%) were monosomy X, seven cells (6.6%) were triple X, and the others were disomy X. Conclusion: Mosaic 45,X/46,XX at amniocentesis may be in fact mosaic 45,X/47,XXX/46,XX and can be associated with a favorable fetal outcome and perinatal progressive decrease of the 45,X cell line

Genetic counseling of a prenatally detected familial 18.79-kb Xp21.1 microduplication encompassing exon 13 of DMD in a pregnancy with no apparent phenotypic abnormalities in the male carriers in the family

Objective: We present genetic counseling of a prenatally detected familial 18.79-kb Xp21.1 microduplication encompassing exon 13 of DMD in a pregnancy with no apparent phenotypic abnormalities in the male carriers in the family. Case report: A 35-year-old, gravida 2, para 0, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed an 18.79-kb Xp21.1 microduplication, or arr Xp21.1 (32,608,400–32,627,193) × 2.0 [GRCh37 (hg19)] encompassing only exon 13 of the gene of DMD (31,137,345–33,357,706) [GRCh37 (hg19)]. Multiplex ligation-dependent probe amplification (MLPA) analysis of the family showed that the mother and her 32-year-old brother carried the same duplication but without apparent phenotypic abnormalities and no features of DMD. Prenatal ultrasound was normal. She was referred for genetic counseling at 24 weeks of gestation, and continuing pregnancy was advised. At 38 weeks of gestation, a 3530-g phenotypically normal male baby was delivered. aCGH analysis of the umbilical cord confirmed the result of arr Xp21.1 (32,608,400–32,627,193) × 2.0 [GRCh37 (hg19)] encompassing only exon 13 of the gene of DMD (31,137,345–33,357,706) [GRCh37 (hg19)]. Conclusion: Xp21.1 microduplication encompassing exon 13 of the DMD gene can be a benign genetic variant