Chien-Wen Yang

Prenatal diagnosis and molecular cytogenetic characterization of a 1.07-Mb microdeletion at 5q35.2–q35.3 associated with NSD1 haploinsufficiency and Sotos syndrome

OBJECTIVE To present prenatal diagnosis and molecular cytogenetic characterization of a de novo 5q35 microdeletion associated with Sotos syndrome. METHODS This was the first pregnancy of a 29-year-old woman. The pregnancy was uneventful until 27 weeks of gestation when left ventriculomegaly was first noted. At 31 weeks of gestation, polyhydramnios, macrocephaly, and ventriculomegaly were prominent on ultrasound, and left pyelectasis and bilateral ventriculomegaly were diagnosed on magnetic resonance imaging. The woman underwent amniocentesis and cordocentesis at 32 weeks of gestation. Conventional cytogenetic analysis was performed using cultured amniocytes and cord blood lymphocytes. Array comparative genomic hybridization (aCGH) was performed on uncultured amniocytes and parental blood. Metaphase fluorescence in situ hybridization (FISH) was performed on cultured lymphocytes. RESULTS Conventional cytogenetics revealed a karyotype of 46,XX. aCGH on uncultured amniocytes revealed a de novo 1.07-Mb microdeletion at 5q35.2-q35.3 encompassing NSD1. Metaphase FISH analysis on the cord blood lymphocytes confirmed the deletion at 5q35.2. The postnatal phenotype was consistent with Sotos syndrome. CONCLUSION Fetuses with Sotos syndrome may present macrocephaly, polyhydramnios, ventriculomegaly, and pyelectasis in the third trimester. aCGH and metaphase FISH are useful for rapid diagnosis of 5q35 microdeletion associated with Sotos syndrome.

Mosaic trisomy 15 at amniocentesis: Prenatal diagnosis, molecular genetic analysis and literature review

OBJECTIVE To present prenatal diagnosis of mosaic trisomy 15 at amniocentesis. MATERIALS AND METHODS A 37-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Cytogenetic analysis of cultured amniocytes revealed a karyotype of 47,XY,+15[2]/46,XY[17]. She was referred for repeated amniocentesis at 19 weeks of gestation. Array comparative genomic hybridization (aCGH), interphase fluorescence in situ hybridization (FISH) and quantitative fluorescent polymerase chain reaction assays on uncultured amniocytes, conventional cytogenetic analysis and aCGH on cultured amniocytes, and FISH on uncultured urinary cells after birth were applied. Cordocentesis revealed a karyotype of 46,XY. RESULTS At repeated amniocentesis, cultured amniocytes revealed a karyotypes of 46,XY [22 colonies], FISH on uncultured amniocytes revealed 21.2% (22/104 cells) mosaicism for trisomy 15, aCGH on uncultured amniocytes revealed a genomic gain (log2 ratio = 0.3) in chromosome 15, quantitative fluorescent polymerase chain reaction on uncultured amniocytes excluded uniparental disomy 15 (UPD 15), and aCGH on culture amniocytes revealed no genomic imbalance in chromosome 15. A healthy 3700 g male baby was delivered at 38 weeks of gestation with no phenotypic abnormalities at age 6 months. FISH on uncultured urinary cells at birth and at age 6 months revealed mosaic trisomy 15 levels of 20% (13/65 cells) and 12.2% (6/49 cells), respectively. CONCLUSION Prenatal diagnosis of mosaic trisomy 15 at amniocentesis should alert doctors about the occurrence of UPD 15 and a clinically significant phenotype. The present case provides evidence for cytogenetic discrepancy between uncultured and cultured amniocytes in mosaic trisomy 15 at amniocentesis. It is possible that the abnormal cell lines of amniocytes with trisomy 15 disappear after long-term cell culture.

Interphase fluorescence in situ hybridization characterization of mosaicism using uncultured amniocytes and cultured stimulated cord blood lymphocytes in prenatally detected Pallister-Killian syndrome.

OBJECTIVE This study aims to present molecular cytogenetic characterization of Pallister-Killian syndrome (PKS). MATERIALS AND METHODS A 37-year-old woman underwent amniocentesis at 18 weeks of gestation. Amniocentesis revealed a karyotype of 47,XY,+i(12)(p10)[6]/48,XY,+i(12)(p10)×2[1]/46,XY[6]. Repeated amniocentesis was performed at 20 weeks of gestation. Array comparative genomic hybridization (aCGH) was performed using uncultured amniocytes, cord blood, and skin. Quantitative fluorescent polymerase chain reaction (QF-PCR) was performed using uncultured amniocytes and parental bloods. Interphase fluorescence in situ hybridization (FISH) analysis was performed using uncultured amniocytes and cultured stimulated cord blood lymphocytes. Conventional cytogenetic analysis was performed using cultured cells from amniotic fluid, skin, placenta, umbilical cord, and cord blood. RESULTS Repeated amniocentesis revealed a mosaic tetrasomy 12p level of 25% (10/40), cultured cord blood lymphocytes had no mosaicism, cultured skin fibroblasts had a mosaic tetrasomy 12p level of 52.5% (21/40), umbilical cord fibroblasts had a mosaic tetrasomy 12p level of 72.5% (29/40), and the placental cells had a mosaic tetrasomy 12p level of 2.5% (1/40) on conventional cytogenetics. An aCGH analysis revealed that the increases in gene dosage in 12p for uncultured amniocytes, skin, and cord blood were the log2 ratios of 0.9, 0.7, and 0.7, respectively. Interphase FISH on uncultured amniocytes revealed a mosaic level of 73.1% (49/67) (tetrasomy 12p: 33; hexasomy 12p: 16). Interphase FISH analysis of stimulated cultured cord blood lymphocytes revealed a mosaic level of 58.3% (60/103) (tetrasomy 12p: 51; hexasomy 12p: 9). CONCLUSION In the diagnosis of PKS by conventional culture cytogenetics, cord blood samplings and placental samplings are prone to a negative result when compared with amniocentesis. Whenever cord blood sampling is applied for prenatal diagnosis of PKS, aCGH on uncultured cord blood or interphase FISH on cultured cord blood can be used for the diagnosis, in addition to conventional cytogenetics.

Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8)(::p11.22→q11.21::) in an 18-year-old female with short stature, obesity, attention deficit hyperactivity disorder, and intellectual disability

OBJECTIVE We present molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 8. MATERIALS AND METHODS An 18-year-old female presented with short stature, obesity, developmental delay, speech delay, dyslexia, attention deficit hyperactivity disorder, and intellectual disability. Cytogenetic analysis of the peripheral blood revealed a karyotype of 47,XX,+mar[22]/46,XX[18]. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy. RESULTS Array comparative genomic hybridization analysis of the blood revealed a result of arr 8p11.22q11.21 (39,136,065-49,725,726)×2.80 (Log2 ratio=0.49), consistent with 70-80% mosaicism, encompassing 33 OMIM genes including GOLGA7, AGPAT6, NKX6-3, KAT6A, and FNTA. The sSMC(8) was r(8)(::p11.22→q11.21::). Metaphase fluorescence in situ hybridization analysis using the probes of RP11-754D24 (8p11.21) and RP11-769N21 (8q11.21) showed the sSMC(8) in 12/27 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction analysis excluded uniparental disomy 8. CONCLUSION Mosaic sSMC(8) derived from r(8)(::p11.22→q11.21::) can be associated with obesity, intellectual disability, and attention deficit hyperactivity disorder.

Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8)(::p12→q13.1::) associated with phenotypic abnormalities

OBJECTIVE We present molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 8. MATERIALS AND METHODS A 35-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar[20]/46,XY[39]. However, array comparative genomic hybridization analysis on the subcultured amniocytes revealed no genomic imbalance. Prenatal ultrasound showed bilateral ventriculomegaly, intrauterine growth restriction, and an enlarged right atrium. At 36 weeks of gestation, a 2380-g baby was delivered with mild facial dysmorphism. The baby postnatally manifested right hydronephrosis, vesicoureteral reflux, hypospadias, hypotonia, strabismus, developmental delay and mild mental retardation. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy. RESULTS The blood had a karyotype of 47,XY,+mar[17]/46,XY[23]. Array comparative genomic hybridization revealed arr 8p12q13.1 (33,476,753-67,428,722)×2.40 (Log2 ratio=0.24) encompassing 98 Online Mendelian Inheritance in Man (OMIM) genes including CHD7, consistent with 30-40% mosaicism for r(8)(::p12→q13.1::). Metaphase fluorescence in situ hybridization identified the sSMC(8) in 21/33 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction excluded uniparental disomy 8. CONCLUSION Mosaic sSMC(8) derived from r(8)(::p12→q13.1::) can present phenotypic abnormalities. Chromosome 8q12 duplication syndrome should be included in differential diagnosis when an sSMC(8) contains 8q12.2 and CHD7.

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.

OBJECTIVE To present prenatal diagnosis and molecular cytogenetic characterization of mosaic isochromosome 20q at amniocentesis. MATERIALS AND METHODS A 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. RESULTS Conventional 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. CONCLUSION Mosaic 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.

Prenatal diagnosis of low-level mosaicism for trisomy 13 at amniocentesis associated with a favorable outcome

OBJECTIVE We present prenatal diagnosis of low-level mosaicism for trisomy 13 at amniocentesis associated with a favorable outcome. CASE REPORT A 35-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+13[5]/46,XY[20]. Oligonucleotide array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed arr [GRCh37] (13)×3 [0.10], (X,Y)×1 compatible with trisomy 13 mosaicism. Prenatal ultrasound was unremarkable. Repeat amniocentesis was performed at 21 weeks of gestation. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed a mosaic trisomy 13 level of 10% (10/100 cells). aCGH analysis on uncultured amniocytes revealed a result of arr 13q12.11q34 (20,407,323-115,092,619)×2.1 with a log2 ratio of 0.06 compatible with a 10% level of mosaicism. Polymorphic DNA marker analysis excluded uniparental disomy 13. The parental karyotypes were normal. Conventional cytogenetic analysis using cultured amniocytes at repeat amniocentesis revealed a karyotype of 46,XY in 23/23 colonies. The pregnancy was carried to 37 weeks of gestation, and a 3600-g phenotypically normal male baby was delivered. When examined at 8 months of age, the infant was doing well and was normal in psychomotor and growth development. The peripheral blood had a karyotype of 46,XY, and interphase FISH analysis on uncultured urinary cells revealed a mosaic trisomy 13 level of 4.4% (2/45 cells). CONCLUSION Low-level true mosaicism for trisomy 13 at amniocentesis without ultrasound abnormalities can be associated with a favorable fetal outcome.

Prenatal diagnosis of a familial 1q21.1-q21.2 microdeletion in a fetus with polydactyly of left foot on prenatal ultrasound

OBJECTIVE We present prenatal diagnosis of a familial 1q21.1-q21.2 microdeletion in a fetus with polydactyly of left foot on prenatal ultrasound. CASE REPORT A 30-year-old, gravida 2, para 1, woman underwent amniocentesis at 22 weeks of gestation because of fetal polydactyly of left foot and echogenic heart foci on prenatal ultrasound. She and her husband and the 2-year-old son were healthy, and there was no family history of mental disorders, skeletal abnormalities and congenital malformations. Amniocentesis revealed a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a 1.317-Mb 1q21.1-q21.2 microdeletion encompassing PRKAB2, FMO5, CHD1L, BCL9, ACP6, GJA5, GJA8 and GPR89B. aCGH analysis of the family members revealed that the phenotypically normal father and elder son carried the same 1q21.1-q21.2 microdeletion. The mother did not have such a deletion. The parents elected to continue the pregnancy, and a 3416-g female baby was delivered at 40 weeks of gestation with neither facial dysmorphism nor gross abnormalities except postaxial polydactyly of the left foot. CONCLUSION Fetuses with a 1q21.1-q21.2 microdeletion may present polydactyly on prenatal ultrasound, and aCGH is helpful for prenatal diagnosis under such a circumstance.

Molecular cytogenetic characterization and prenatal diagnosis of familial Xp22.33 microdeletion encompassing short stature homeobox gene in a male fetus with a favorable outcome

a Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan b Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan c Department of Biotechnology, Asia University, Taichung, Taiwan d School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan e Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan f Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan g Genephile Bioscience Laboratory, Kos Obstetrics and Gynecology, Taipei, Taiwan h Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan i Department of Medicine, MacKay Medical College, New Taipei City, Taiwan j Department of Early Childhood Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan k Gene Biodesign Co. Ltd, Taipei, Taiwan l Department of Bioengineering, Tatung University, Taipei, Taiwan

Molecular cytogenetic characterization of a duplication of 15q24.2-q26.2 associated with anencephaly and neural tube defect

OBJECTIVE We present molecular cytogenetic characterization of a duplication of 15q24.2-q26.2 associated with anencephaly and neural tube defect (NTD). CASE REPORT A 35-year-old pregnant woman was found to have a fetus with anencephaly by prenatal ultrasound at 12 weeks of gestation. The pregnancy was subsequently terminated, and a malformed fetus was delivered with anencephaly. Cytogenetic analysis of the cultured placental tissues revealed a karyotype of 46,XX,dup(15) (q24.2q26.2). Parental karyotypes were normal. Array comparative genomic hybridization analysis of the placental tissues revealed a 20.36-Mb duplication of 15q24.2-q26.2 encompassing 100 Online Mendelian Inheritance of in Man (OMIM) genes including LINGO1, MTHFS, KIF7 and CHD2. Metaphase fluorescence in situ hybridization analysis using 15q25.1-specidic probe confirmed a duplication of 15q25.1. Polymorphic DNA marker analysis showed a maternal origin of the duplication. CONCLUSION A duplication of chromosome 15q24.2-q26.2 can be associated with NTD.