High-level mosaic trisomy 14 at amniocentesis in a pregnancy associated with congenital heart defects and intrauterine growth restriction on fetal ultrasound

ObjectiveWe present high-level mosaic trisomy 14 at amniocentesis in a pregnancy associated with congenital heart defects (CHD) and intrauterine growth restriction (IUGR).Case reportA 34-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. This pregnancy was conceived by in vitro fertilization and embryo transfer (IVF-ET). Amniocentesis revealed a karyotype of 47,XX,+14[9]/46,XX[13], consistent with 40.9% (9/22 colonies) mosaicism for trisomy 14. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed 61% mosaicism for trisomy 14. Prenatal ultrasound at 22 weeks of gestation showed a malformed fetus with double outlet of right ventricle (DORV), ventricular septal defect (VSD), pulmonary stenosis and severe IUGR with the growth parameters equivalent to 18 weeks of gestation. The pregnancy was terminated at 23 weeks of gestation, and a 278-g female fetus was delivered with facial dysmorphism of hypertelorism, low-set small ears and wide depressed nasal bridge. Quantitative fluorescent polymerase chain reaction (QF-PCR) analysis on the DNA extracted from parental bloods, cord blood, umbilical cord and placenta confirmed a maternal origin of the extra chromosome 14 and excluded uniparental disomy (UPD) 14. The umbilical cord had a karyotype of 47,XX,+14[7]/ 46,XX[13], and the placenta had a karyotype of 47,XX,+14[4]/46,XX[36].ConclusionsHigh-level mosaic trisomy 14 at amniocentesis can be associated with abnormal ultrasound findings of CHD and IUGR.     

First-trimester prenatal diagnosis of Ellis–van Creveld syndrome

ObjectiveTo present the perinatal findings and first-trimester molecular and transabdominal ultrasound diagnosis of a fetus with Ellis–van Creveld (EvC) syndrome.Case ReportA 35-year-old woman was referred for genetic counseling at 13 weeks of gestation because of a family history of skeletal dysplasia. She had experienced one spontaneous abortion, and delivered one male fetus and one female fetus with EvC syndrome. During this pregnancy, a prenatal transabdominal ultrasound at 13⁺⁴ weeks of gestation revealed a nuchal translucency (NT) thickness of 2.0 mm, an endocardial cushion defect, postaxial polydactyly of bilateral hands, and mesomelic dysplasia of the long bones. Amniocentesis was performed at 13⁺⁵ weeks of gestation. Results of a cytogenetic analysis revealed a karyotype of 46,XX and that of a molecular analysis revealed compound heterozygous mutations of c.1195C>T and c.871-2_894del26 in the EVC2 gene. Prenatal ultrasound at 16 weeks of gestation showed a fetus with short limbs, an endocardial cushion defect, and postaxial polydactyly of bilateral hands. The parents decided to terminate the pregnancy, and a 116-g female fetus was delivered with a narrow thorax, shortening limbs, and postaxial polydactyly of the hands.ConclusionPrenatal diagnosis of an endocardial cushion defect with postaxial polydactyly should include a differential diagnosis of EvC syndrome in addition to short rib–polydactyly syndrome, Bardet–Biedl syndrome, orofaciodigital syndrome, Smith–Lemli–Opitz syndrome, and hydrolethalus syndrome.     

Detection of paternal origin of fetal trisomy 18 in a pregnancy conceived by assisted reproductive technology and in vitro fertilization

ObjectiveWe present detection of paternal origin of fetal trisomy 18 in a pregnancy conceived by assisted reproductive technology (ART) and in vitro fertilization (IVF).Case reportA 39-year-old woman underwent ART and IVF because of primary infertility. The woman was infertile because of myoma and endometriosis. Her husband was 39 years old, and the sperm analysis was normal. The couple was phenotypically normal. This pregnancy was conceived successfully by IVF. She received non-invasive prenatal testing at 11 weeks of gestation, the result showed a high risk for trisomy 18. She underwent chorionic villus sampling at 12 weeks of gestation, and the result was 47,XY,+18 in 24/24 cultured chorionic villi cells. Prenatal ultrasound findings were unremarkable. She underwent amniocentesis at 17 weeks of gestation, and the result was 47,XY,+18 in 20/20 colonies of cultured amniocytes. The pregnancy was subsequently terminated. Postnatal cytogeneic analysis confirmed the prenatal diagnosis. Polymorphic DNA marker analysis on the DNAs extracted from the umbilical cord and parental bloods showed a paternal origin of the extra chromosome 18, indicating a paternal origin of fetal trisomy 18. Cytogenetic analysis of paternal blood revealed a karyotype of 46,XY.ConclusionFetal trisomy 18 in pregnancies conceived by ART may be of paternal origin, and determination of paternal origin by polymorphic DNA marker analysis is useful for genetic counseling under such a circumstance.     

Detection of hypermethylation at H19DMR at amniocentesis in a fetus with overgrowth,distended abdomen and Beckwith-Wiedemann syndrome

ObjectiveWe present detection of hypermethylation at H19 differentially methylated region (DMR) at amniocentesis in a fetus with overgrowth, distended abdomen and Beckwith-Wiedemann syndrome (BWS).Case reportA 31-year-old, gravida 2, para 1, woman was referred for genetic counseling at 22 weeks of gestation because of fetal overgrowth with fetal biometry equivalent to 24 weeks of gestation and a distended abdomen with an abdominal circumference equivalent to 26 weeks of gestation. She did not undergo any assisted reproductive technology during this pregnancy. Amniocentesis was performed at 23 weeks of gestation. Conventional cytogenetic analysis revealed a karyotype of 46,XX. Array comparative genomic hybridization analysis on the DNA extracted from uncultured amniocytes revealed no genomic imbalance. Methylation analysis on the DNA extracted from amniocytes revealed hypermethylation at H19DMR [imprinting center 1 (IC1)] and normal methylation at KvDMR1 (IC2). The methylation test confirmed the diagnosis of BWS in the fetus. The parents decided to continue the pregnancy. At 36 weeks of gestation, a 4000-g female baby was delivered with macroglossia, ear tags and creases, and an enlarged liver, consistent with the phenotype of BWS.ConclusionPrenatal diagnosis of fetal overgrowth should include a differential diagnosis of BWS, and methylation analysis of H19DMR (IC1) and KvDMR1 (IC2) is useful under such a circumstance.     

Prenatal diagnosis of persistent left superior vena cava,polyhydramnios and a small gastric bubble in a fetus with VACTERL association

ObjectiveWe reported a fetus that presenting with persistent left superior vena cava (PLSVC), polyhydramnios, and a small gastric bubble during prenatal examination and identified VACTERL association after birth.Case reportA 34-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age and the result was normal. Subsequently, an ultrasound revealed single umbilical artery (SUA) at 21 weeks of gestation. She received a detailed fetal anatomy survey that presented the same findings and PLSVC. A small visible gastric bubble was noted at that time, and the other organs were unremarkable. Polyhydramnios was identified at 30 weeks of gestation and amnioreduction was subsequently performed at 32 weeks of gestation. However, polyhydramnios was persisted despite amnioreduction and intrauterine growth restriction was also detected. A cesarean section was performed because of fetal distress at 36 + 2 weeks, and a 1832-g female baby was delivered. Pre-axial polydactyly at left thumb, SUA and esophageal atresia with distal tracheoesophageal fistula (TEF) were identified after birth. The neonate died at age of 4 days because of surgical complication following esophageal anastomosis.ConclusionPrenatal diagnosis of PLSVC associated with polyhydramnios and a small gastric bubble may indicate esophageal atresia with TEF, and further examination for associated syndromes such as VACTERL association is warranted.     

First-trimester molecular diagnosis of complete hydatidiform mole associated with dizygotic twin pregnancy conceived by intrauterine insemination

ObjectiveTo present first-trimester molecular diagnosis of complete hydatidiform mole (CHM) associated with dizygotic twin pregnancy conceived by intrauterine insemination.Materials and methodsA 32-year-old woman presented to the hospital with a huge complex cystic mass measuring about 8.5 cm × 4.1 cm in the uterine cavity and a living co-existing fetus with fetal biometry equivalent to 9 weeks. She underwent chorionic villus sampling at 13 weeks of gestation, and microsatellite genotyping for molar pregnancy test was applied. A molar pregnancy test was performed by a short tandem repeat (STR) identifier polymerase chain reaction (PCR) polymorphic marker analysis. The pregnancy was terminated at 14 weeks of gestation. Postnatal polymorphic DNA marker analysis of the placenta by quantitative fluorescent PCR (QF-PCR) was performed. Analysis of maternal blood total β-human chorionic gonadotropin revealed a high level of 551,600 mIU/mL at 10 weeks of gestation and a level of 1.0 mIU/mL at 15 weeks postpartum. The woman was doing well at 4 months after delivery.ResultsThe results of STR identifier PCR polymorphic marker analysis showed androgenic conception in the complex cystic mass and biparental conception in the living fetus. Pathological analysis of the cystic mass confirmed the diagnosis of CHM. The results of QF-PCR showed biparental inheritance in the normal fetus and complete paternal homozygosity in the CHM of the abnormal fetus in all STRs, indicating dizygotic twinning and CHM of monospermy.ConclusionPrenatal sonographic diagnosis of placentomegaly with many grape-like vesicles should include a differential diagnosis of CHM, partial hydatidiform mole (PHM), placental mesenchymal dysplasia (PMD), and recurrent hydatidiform mole. Microsatellite genotyping for molar pregnancy testing and zygosity testing is useful in cases of prenatal diagnosis of placentomegaly associated with many grape-like vesicles and a twin pregnancy with a living fetus in the first trimester.     

Female pseudohermaphroditism in a prenatally diagnosed cloacal malformation with hydronephrosis,dilated bladder,hydrometrocolpos, and oligohydramnios

ObjectiveTo present female pseudohermaphroditism in a prenatally diagnosed cloacal malformation.Case reportA 29-year-old, primigravid woman referred for counseling at 17 weeks of gestation because of oligohydramnios and an intra-abdominal cyst in the fetus. The woman was not exposed to any virilizing agent during this pregnancy. She did not undergo any assisted reproductive technology for this pregnancy. Level II ultrasound showed a singleton with fetal biometry equivalent to 16 weeks, oligohydramnios, hydrometrocolpos, dilated bladder, and bilateral hydronephrosis. A diagnosis of cloacal malformation was made. The parents elected to terminate the pregnancy at 18 weeks of gestation. A 196-g fetus was delivered with a distended abdomen, a phallus-like structure, a small perineal opening below the phallus-like structure, and an imperforate anus. At birth, the fetus was misdiagnosed as a male with an imperforate anus and a perineal fistula. Cytogenetic analysis of the cord blood revealed a karyotype of 46,XX. Array comparative genomic hybridization analysis of the fetal tissues revealed no genomic imbalance. The phallus-like structure was an enlarged clitoris and contained accessory phallic urethra.ConclusionPrenatal diagnosis of cloacal malformation with ambiguous genitalia should be paid attention to avoid misdiagnosis of a male with an imperforate anus and a perineal fistula. Cytogenetic analysis is helpful to determine the sex under such circumstances.     

Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from 2q11.1-q12.1 associated with fetal bilateral radial dysplasia

ObjectiveWe present prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from 2q11.1-q12.1 associated with fetal bilateral radial dysplasia.Case reportA 27-year-old woman underwent amniocentesis at 18 weeks of gestation because of club hands on fetal ultrasound. The internal organs of the fetus were normal. Amniocentesis revealed a karyotype of 47,XY,+mar [13]/46,XY [11]. The parental karyotypes were normal. Simultaneous array comparative genomic hybridization (aCGH) analysis of the DNA extracted from uncultured amniocytes revealed the result of arr 2q11.1q12.1 (95,529,039–102,825,556) × 3.0 [GRCh37 (hg19)]. The pregnancy was terminated at 20 weeks of gestation, and a malformed fetus was delivered with isolated bilateral radial dysplasia. The cord blood had a karyotype of 47,XY,+mar[24]/46,XY[16]. Polymorphic DNA marker analysis of the DNAs extracted from umbilical cord and parental bloods excluded uniparental disomy for chromosome 2. Metaphase fluorescence in situ hybridization analysis confirmed an sSMC derived from chromosome 2q11.1-q12.1 in cultured amniocytes.ConclusionHigh-level mosaicism for an sSMC derived from chromosome 2q11.1-q12.1 can be associated with fetal abnormalities.     

Detection of de novo del(18)(q22.2) and a familial of 15q13.2-q13.3 microduplication in a fetus with congenital heart defects

ObjectiveWe present detection of de novo del(18)(q22.2) and a familial 15q13.2-q13.3 microduplication in a fetus with congenital heart defects (CHD).Case reportA 27-year-old, primigravid woman was referred for genetic counseling because of fetal CHD. Prenatal ultrasound at 17 weeks of gestation revealed pericardial effusion, cardiomegaly and a large ventricular septal defect. The pregnancy was subsequently terminated at 18 weeks of gestation, and a 192-g female fetus was delivered with facial dysmorphism. Cytogenetic analysis of the umbilical cord revealed a karyotype of 46,XX,del(18)(q22.2). The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) of the placental tissue revealed a 2.08-Mb 15q13.2-q13.3 microduplication encompassing KLF13 and CHRNA7, and a 10.74-Mb 18q22.2-q23 deletion encompassing NFATC1. The phenotypically normal father carried the same 2.08-Mb 15q13.2-q13.3 microduplication. Polymorphic DNA marker analysis confirmed a paternal origin of the distal 18q deletion.ConclusionPrenatal diagnosis of CHD should include a complete genetic study of the embryonic tissues, and the acquired information is useful for genetic counseling.     

Prenatal diagnosis and molecular cytogenetic characterization of a chromosome 1q42.3-q44 deletion in a fetus associated with ventriculomegaly on prenatal ultrasound

ObjectiveWe present prenatal diagnosis and molecular cytogenetic characterization of a chromosome 1q42.3-q44 deletion in a fetus associated with ventriculomegaly on prenatal ultrasound, and we discuss the genotype–phenotype correlation.Case reportA 36-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XX,del(1) (q42.3q44). Simultaneous array comparative genomic hybridization analysis on uncultured amniocytes revealed arr 1q42.3q44 (234,747,397–246,081,267) × 1 [GRCh37 (hg19)] with an 11.33-Mb 1q42.3-q44 deletion encompassing RGS7, FH, CEP170, AKT3, ZBTB18 and HNRNPU. The parental karyotypes were normal. Prenatal ultrasound at 20 weeks of gestation revealed bilateral ventriculomegaly and dilation of the third ventricle. The pregnancy was subsequently terminated, and a malformed female fetus was delivered with characteristic facial dysmorphism. Postnatal conventional and molecular cytogenetic analyses confirmed the prenatal diagnosis. Polymorphic DNA marker analysis showed a paternal origin of the distal 1q deletion in the fetus.ConclusionFetuses with a chromosome 1q42.3-q44 deletion may present ventriculomegaly on prenatal ultrasound. Prenatal diagnosis of ventriculomegaly should include a differential diagnosis of chromosome 1q distal deletions, and aCGH is useful under such a circumstance.     

Rapid detection of de novo P253R mutation in FGFR2 using uncultured amniocytes in a pregnancy affected by polyhydramnios,Blake's pouch cyst,and Apert syndrome

ObjectiveTo present prenatal ultrasound and molecular genetic diagnosis of Apert syndrome.Case ReportA 30-year-old, gravida 3, para 2 woman was referred for genetic counseling at 32 weeks of gestation because of polyhydramnios and craniofacial and digital abnormalities in the fetus. She had undergone amniocentesis at 18 weeks of gestation because of maternal anxiety. Results of amniocentesis revealed a karyotype of 46,XX. A prenatal ultrasound at 32 weeks of gestation revealed a female fetus with a fetal biometry equivalent to 32 weeks, polyhydramnios with an increased amniotic fluid index of 26.1 cm, frontal bossing, midface hypoplasia, hypertelorism, Blake's pouch cyst with an apparent posterior fossa cyst in communication with the fourth ventricle on axial images, digital fusion, and bilateral syndactyly of the hands and feet. A DNA testing for the FGFR2 gene was immediately performed using uncultured amniocytes obtained by repeated amniocentesis, which revealed a heterozygous c.758C>G, CCT>CGT transversion leading to a p.Pro253Arg (P253R) mutation in the FGFR2 gene. Subsequently, a diagnosis of Apert syndrome was made. Molecular analysis of the FGFR2 gene in the parents did not reveal such a mutation. The fetus postnatally manifested frontal bossing, midface hypoplasia, and bilateral syndactyly of the hands (mitten hands) and feet.ConclusionPrenatal diagnosis of polyhydramnios, frontal bossing, and midface hypoplasia associated with brain and digital abnormalities should include a differential diagnosis of Apert syndrome. A molecular analysis of FGFR2 using uncultured amniocytes is useful for rapid confirmation of Apert syndrome at prenatal diagnosis.     

Osteogenesis imperfecta type I: second-trimester diagnosis and incidental identification of a dominant COL1A1 deletion mutation in the paucisymptomatic father

ObjectiveTo present second-trimester ultrasound and molecular diagnosis for osteogenesis imperfecta (OI) type I in a female fetus and incidental identification of a dominant COL1A1 deletion mutation in her paucisymptomatic father.Case ReportA 30-year-old, primigravid woman was referred for genetic counseling in the second trimester because of bowing of the fetal lower limbs. She and her husband were non-consanguineous, and there was no family history of skeletal dysplasias. Prenatal ultrasound at 22 weeks of gestation revealed short and curved right femur and left tibia, and a short left fibula. The lengths of other long bones were normal. The husband was 158 cm tall, had blue sclerae, a history of habitual subluxation and dislocation of bilateral elbows and left knee, and an episode of left ulna fracture, and was not aware of his being affected with OI type I. The woman underwent amniocentesis. Cytogenetic analysis revealed a karyotype of 46,XX. Molecular analysis of the amniocytes revealed a heterozygous deletion mutation of c.1064_1068delCTGGT in exon 17 of the COL1A1 gene. By genetic testing the husband was found to carry the same mutation. Despite counseling of favorable outcome for OI type I with the parents, the woman elected to terminate the pregnancy. Postnatal skeletal X-ray findings were consistent with OI type I.ConclusionPrenatal ultrasound diagnosis of mild forms of OI should include molecular analysis of type I collagen genes in both fetus and parents. Molecular genetic analysis of the family may incidentally identify a collagen gene mutation in the paucisymptomatic affected parent.     

Short rib-polydactyly syndrome type II (Majewski): prenatal diagnosis, perinatal imaging findings and molecular analysis of the NEK1 gene

ObjectiveTo demonstrate perinatal imaging findings and to investigate the mutation in the NEK1 gene in a fetus with type II short rib-polydactyly syndrome (SRPS) (Majewski).Case ReportA 34-year-old woman with a past history of fetal SRPS was referred to the hospital at 16 weeks of gestation because of sonographic diagnosis of short limbs in the fetus. Fetal ultrasound revealed short ribs, short limbs, absence of tibiae, polydactyly, syndactyly and choroid plexus cysts. At 21 weeks of gestation, polycystic kidneys were found. The pregnancy was terminated, and a fetus was delivered with facial dysmorphism, a median cleft lip, a narrow chest, micromelia, aplasia of tibiae, hypoplastic nails, syndactyly and postaxial polydactyly. The karyotype was 46,XX. Molecular analysis of fetal tissues showed a paternal-origin heterozygous splice site mutation in intron 7 (c.465-1 G>A) in the NEK1 gene, but no mutations in the genes of WDR35, DYNC2H1, IFT80, EVC and EVC2. The NEK1 mutation causes an alteration of the splice acceptor site of intron 7 (IVS7-1 G>A). No second mutation was identified.ConclusionTibial aplasia, choroid plexus cysts and polycystic kidneys can be prominent prenatal ultrasound findings of type II SRPS. The present case provides evidence for a correlation of NEK1 mutation with type II SRPS.     

Prenatal diagnosis of maternal uniparental disomy 16 associated with mosaic trisomy 16 at amniocentesis,and pericardial effusion and intrauterine growth restriction in the fetus

ObjectiveWe present prenatal diagnosis of maternal uniparental disomy (UPD) 16 associated with mosaic trisomy 16 at amniocentesis, and pericardial effusion and intrauterine growth restriction (IUGR) in the fetus.Case reportA 38-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age, and the result was 47,XX,+16[2]/46,XX[54]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed 14% mosaicism for trisomy 16 and a paternally inherited 319-kb microdeletion of 15q11.2 encompassing the genes of TUBGCP5, CYFIP1, NIPA2 and NIPA1. Prenatal ultrasound revealed persistent left superior vena cava, pericardial effusion and severe IUGR. Cordocentesis at 23 weeks of gestation revealed a karyotype of 46,XX, but polymorphic DNA marker analysis revealed maternal UPD 16. Repeat amniocentesis was performed at 27 weeks of gestation and revealed a karyotype of 46, XX in 21/21 colonies. Molecular cytogenetic analysis on uncultured amniocytes revealed 22.4% mosaicism (26/116 cells) for trisomy 16 on interphase fluorescence in situ hybridization (FISH) analysis, and 20% mosaicism for trisomy 16 on aCGH. Polymorphic DNA marker analysis on the DNAs extracted from uncultured amniocytes and parental bloods revealed maternal UPD 16. The pregnancy was subsequently terminated, and a fetus was delivered with facial dysmorphism and severe IUGR. The umbilical cord had a karyotype of 47,XX,+16[28]/46,XX[16]. Polymorphic DNA marker analysis on placenta confirmed a maternal origin of trisomy 16.ConclusionCytogenetic discrepancy between cultured amniocytes and uncultured amniocytes may present in mosaic trisomy 16 at amniocentesis. Prenatal diagnosis of mosaic trisomy 16 should alert the association of maternal UPD 16 which may be associated with congenital heart defects and severe IUGR on prenatal ultrasound.     

Risk of miscarriage in women conceiving after medically assisted reproduction with an ultrasound-verified viable pregnancy at 6–8 weeks’ gestation

Research questionWhat is the risk of miscarriage after a viable fetus verified on ultrasound at 6–8 weeks’ gestation among women who conceive with medically assisted reproduction (MAR), stratified by type of fertility treatment?DesignA nationwide register-based cohort study of women identified in the Danish ART-Registry with a viable singleton pregnancy at 6–8 weeks’ gestation between 2007 and 2010 (n = 10,011). Women were identified from The Danish Fetal Medicine Database (DFMD), which holds information on early (between 6–8 and 11–14 weeks) and late (between 11–14 and 22 weeks) miscarriages. The late miscarriage rate was compared with a control group of naturally conceived pregnancies with a viable fetus at 11–14 weeks’ gestation from 2008 to 2010, identified in the DFMD (n = 146,932).ResultsIn the MAR1 cohort, the overall miscarriage rate was 11.8% (1091/9261) after an ultrasound verified viable pregnancy at 6–8 weeks’ gestation. Most miscarriages occurred before the 11–14-week scan (1035/1091 [94.9%]). The early miscarriage rate was slightly higher in women who conceived with frozen embryo transfer compared with intrauterine insemination (IUI), corresponding to an adjusted OR of 1.31 (1.02 to 1.68). We found no significant risk associated with IVF and intracytoplasmic sperm injection compared with IUI pregnancies. The late miscarriage rate was 0.8% in women conceiving with MAR and 0.6% among controls (P = 0.013).ConclusionsAfter adjustment for maternal characteristics, none of the fertility treatment types were associated with an increased risk of miscarriage compared with naturally conceiving women.     

Prenatal diagnosis of low-level mosaic trisomy 17 with maternal uniparental disomy 17 by amniocentesis in a pregnancy with a favorable outcome

ObjectiveWe present prenatal diagnosis low-level mosaic trisomy 17 with maternal uniparental disomy (UPD) 17 at amniocentesis in a pregnancy with a favorable outcome.Materials and methodsA 40-year-old, primigravid woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. This pregnancy was conceived by in vitro fertilization and embryo transfer. Amniocentesis revealed a karyotype of 47,XX,+17 [13]/ 46, XX [23]. Repeat amniocentesis was performed at 21 weeks of gestation. Conventional cytogenetic analysis was applied on cultured amniocytes, parental bloods and cord blood. Simultaneous molecular genetic analysis such as interphase fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and quantitative fluorescent polymerase chain reaction (QF-PCR) assays were applied on uncultured amniocytes. Interphase FISH was applied on postnatal buccal cells.ResultsRepeat amniocentesis revealed a karyotype of 47,XX,+17[6]/46,XX[28]. Genetic analyses on uncultured amniocytes showed the results of mosaic trisomy 17 (12/101 cells = 11.9%) in FISH analysis, no genomic imbalance in aCGH analysis and maternal UPD 17 in QF-PCR assays. The parental karyotypes were normal. Prenatal ultrasound findings were unremarkable. The parents decided to continue the pregnancy, and a 1449-g, phenotypically normal female baby was delivered prematurely at 31 weeks of gestation. The cord blood had a karyotype of 46,XX. She had a normal psychomotor development at age 22 months at follow-up. Interphase FISH analysis on buccal cells showed trisomy 17 signals in 1/66 cells (1.5%).ConclusionsLow-level mosaicism for trisomy 17 associated with maternal UPD 17 detected by amniocentesis without ultrasound abnormality can be associated with a favorable outcome. Molecular genetic analysis of uncultured amniocytes at repeat amniocentesis is useful for confirmation and genetic counseling under such as circumstance.     

Double aneuploidy with Edwards-Klinefelter syndromes (48,XXY,+18) of maternal origin: prenatal diagnosis and molecular cytogenetic characterization in a fetus with arthrogryposis of the left wrist and aplasia of the left thumb

ObjectiveTo present the prenatal diagnosis and molecular investigation of the parental origin and mechanism of nondisjunction underlying an 48,XXY,+18 karyotype in a fetus with congenital abnormalities, and to review the literature.Materials, Methods, and ResultsA 42-year-old woman was referred for amniocentesis at 18 weeks of gestation because of advanced maternal age. Prenatal ultrasound revealed bilateral choroid plexus cysts. Amniocentesis revealed a karyotype of 48,XXY,+18. The parental karyotypes were normal. Level II ultrasound revealed a flexion contracture deformity of the left wrist with absence of the thumb. The pregnancy was terminated at 22 weeks of gestation. A 332 g male fetus was delivered with clenched hands, arthrogryposis of the left wrist, aplasia of the left thumb, micrognathia, low-set ears, hypertelorism, rocker-bottom feet, and a normal penis. Quantitative fluorescent polymerase chain reaction assays using polymorphic DNA markers showed a triallelic pattern with a dosage ratio of 1:1:1 (paternal:maternal:maternal) for chromosome 18-specific markers, and a monoallelic pattern of a single maternal allele for chromosome X-specific markers. The fetus inherited two copies of two different maternal alleles on chromosome 18, and two copies of a single maternal allele on chromosome X. The molecular result, along with the karyotype of 48,XXY,+18, was consistent with the occurrence of nondisjunction of chromosome 18 in a maternal meiosis I error and nondisjunction of chromosome X in a maternal meiosis II error or less likely a postzygotic mitotic error.ConclusionThe present case provides evidence that abnormal separation of chromosomes 18 and X resulting in double aneuploidy may occur in different cell divisions, and such an occurrence is related to advanced maternal age.     

Chromosome 15q overgrowth syndrome: prenatal diagnosis, molecular cytogenetic characterization, and perinatal findings in a fetus with dup(15)(q26.2q26.3)

ObjectiveTo present molecular cytogenetic characterization of a prenatally detected duplication of 15q26.2 → q26.3 in a fetus with overgrowth.Case ReportA 34-year-old para 0 woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a derivative chromosome 15, or der(15), with additional material at the end of the long arm of one chromosome 15. Parental karyotypes were normal. Fetal overgrowth was first noted at 21 weeks of gestation. Repeated amniocentesis was performed at 22 weeks of gestation. Array comparative genomic hybridization revealed a 4.71-Mb duplication from 15q26.2 to 15q26.3 encompassing the IGF1R gene. Fluorescence in situ hybridization analysis using the bacterial artificial chromosome clone probes specific for 15q26.2-q26.3 and the subtelomeric region of 15q showed a direct duplication and no terminal deletion in the der(15). Polymorphic DNA marker analysis determined a paternal origin of the duplication of 15q. Level II ultrasound at 23 weeks of gestation revealed a fetal biometry equivalent to 26 weeks. The pregnancy was subsequently terminated, and a 1062-g (>99^th centile) malformed fetus was delivered at 24 weeks of gestation with craniofacial dysmorphism, craniosynostosis, and overgrowth.ConclusionThe present case provides evidence for prenatal overgrowth, craniosynostosis, and characteristic facial dysmorphism in association with a duplication of 15q26.2 → q26.3 and a duplication of the IGF1R gene. Prenatal diagnosis of fetal overgrowth should include a differential diagnosis of the chromosome 15q overgrowth syndrome.     

Mosaic 45,X/46, XX at amniocentesis with high-level mosaicism for 45,X in a pregnancy with a favorable fetal outcome and postnatal decrease of the 45,X cell line

ObjectiveWe present mosaic 45,X/46, XX at amniocentesis with high-level mosaicism for 45,X in a pregnancy with a favorable fetal outcome and postnatal decrease of the 45,X cell line.Case reportA 20-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of the non-invasive prenatal testing (NIPT) result of −4.82 Z score in sex chromosome at 12 weeks of gestation suggestive of Turner syndrome in the fetus. Amniocentesis revealed a karyotype of 45,X [18]/46,XX [15], and simultaneous multiplex ligation-dependent probe amplification (MLPA) on the DNA extracted from uncultured amniocytes showed mosaic Turner syndrome. Prenatal ultrasound and parental karyotypes were normal. She was referred for genetic counseling at 24 weeks of gestation, and continuing pregnancy was encouraged. At 39 weeks of gestation, a 2550-g phenotypically normal female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 45,X [24]/46,XX [16], 45,X [23]/46,XX [17] and 45,X [28]/46,X,del(X) (q23)[12], respectively. When follow-up at age two months, the neonate was phenotypically normal in development. The peripheral blood had a karyotypes of 45,X [16]/46,XX [24]. Interphase fluorescence in situ hybridization (FISH) analysis on 103 buccal mucosal cells showed normal disomy X signals in all cells.ConclusionHigh-level mosaicism for 45,X in 45,X/46, XX at amniocentesis can be associated with a favorable fetal outcome, cytogenetic discrepancy in various tissues, and postnatal decrease of the 45,X cell line.     

Rapid diagnosis of trisomy 18 of maternal origin by quantitative fluorescent polymerase chain reaction analysis following tissue culture failure for conventional cytogenetic analysis in a fetus with holoprosencephaly,ventricular septal defect,arthrogryposis of bilateral wrists and aplasia of the thumbs

ObjectiveWe present rapid diagnosis of trisomy 18 of maternal origin by quantitative fluorescent polymerase chain reaction (QF-PCR) analysis following tissue culture failure for conventional cytogenetic analysis in a fetus with holoprosencephaly (HPE), ventricular septal defect (VSD), arthrogryposis of bilateral wrists and aplasia of the thumbs.Case reportA 22-year-old, primigravid woman was referred for first-trimester ultrasound screening at 13 weeks of gestation, and the fetus was found to have HPE and VSD. The pregnancy was subsequently terminated at 14 weeks of gestation, and a malformed fetus was delivered with cebocephaly, arthrogryposis of bilateral wrists and aplasia of the thumbs. The umbilical cord and placental tissues were collected for genetic analysis. However, tissue culture failure for conventional cytogenetic analysis occurred because of contamination. QF-PCR analysis using the polymorphic DNA markers of D18S1369 (18q12.2) and D18S1361 (18q22.3) confirmed trisomy 18 of maternal origin.ConclusionQF-PCR analysis is useful for rapid confirmation of trisomy 18 and the parental origin when tissue culture failure for conventional cytogenetic analysis occurs in pregnancy suspicious of fetal trisomy 18.