BACKGROUND: Copy number variation sequencing (CNV-seq) is crucial in prenatal diagnosis, but its limitations in detecting polyploidy, maternal cell contamination (MCC), and uniparental disomy (UPD) restrict its application in the analysis of products of conception (POCs). This study aimed to investigate an optimal genetic testing strategy for POCs in the era of CNV-seq.
METHODS: CNV-seq and quantitative fluorescent polymerase chain reaction (QF-PCR) were performed in all 4,211 spontaneous miscarriage cases. Different testing strategies were compared and the optimal testing strategies were proposed.
RESULTS: Of the 4,211 cases, 2561 (60.82%) exhibited clinically significant chromosomal abnormalities. CNV-seq alone, without QF-PCR, might misdiagnose 311 (7.39%) cases, including 278 polyploidy, 13 UPD, and 20 MCC. In 20 MCC cases identified by QF-PCR, CNV-seq successfully pinpointed the cause of miscarriage in 13 cases. Furthermore, in cases where QF-PCR suggested polyploidy, CNV-seq improved the diagnostic accuracy in 54 (1.28%) hypo/hypertriploidy cases. After comparing four different strategies, the sequential approach (initiating with CNV-seq followed by QF-PCR if necessary) emerged as advantageous, reducing approximately 70% of the cost associated with QF-PCR while maintaining result accuracy.
CONCLUSIONS: We propose an initial CNV-seq followed by QF-PCR if needed-an efficient and cost-effective strategy for the genetic analysis of POCs.

BACKGROUND: Quantitative fluorescent polymerase chain reaction (QF-PCR) is a rapid prenatal diagnostic method for abnormalities on chromosomes 21, 18, and 13 and sex chromosomal aneuploidy. However, the value of QF-PCR in diagnosing chromosomal structural abnormalities is limited. In this article, we report a confusing QF-PCR finding in a pregnant woman who underwent amniocentesis.
METHODS: The short tandem repeat marker AMXY (Xp22.2/Yp11.2) located on the sex chromosome exhibited a trisomic biallelic pattern, indicating that the karyotype of the fetus might be 47,XYY. Chromosome analysis performed on cultured amniocytes showed a normal male karyotype of the fetus. Copy number variation sequencing confirmed a 500 kb duplication at Yp11.2-Yp11.2 (chrY:6610001_ 7110000) and a 250 kb duplication at Yp11.2-Yp11.2 (chrY:7110001_7360000).
CONCLUSIONS: In conclusion, the comprehensive application of different methods could achieve a higher detection rate and accuracy for the prenatal diagnosis of chromosomal disorders through chromosomal testing.

OBJECTIVE: We present rapid confirmation of trisomy 13 of maternal origin by quantitative fluorescent polymerase chain reaction (QF-PCR) following postmortem tissue cell culture failure in a pregnancy with trisomy 13 at amniocentesis and fetal postaxial polydactyly and facial cleft.
METHODS: A 34-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,XX,+13. Prenatal ultrasound revealed postaxial polydactyly. The pregnancy was subsequently terminated, and a malformed fetus was delivered with facial cleft and postaxial polydactyly of the hand and foot. Postmortem cytogenetic analysis of the fetal tissue revealed no growth of the cells due to culture failure, but QF-PCR analysis on the DNA extracted from placenta, umbilical cord and parental bloods confirmed trisomy 13 and maternal origin of the extra chromosome 13.
CONCLUSIONS: QF-PCR analysis is useful for rapid perinatal confirmation of trisomy 13 and the parental origin of the extra chromosome 13, especially under the circumstance of tissue cell culture failure, and the acquired information is useful for genetic counseling.

OBJECTIVE: We present the application of quantitative fluorescent polymerase chain reaction (QF-PCR) for the rapid confirmation of trisomy 13 of maternal origin in a pregnancy with fetal holoprosencephaly (HPE), cyclopia, polydactyly, omphalocele and cell culture failure.
METHODS: A 21-year-old, gravida 2, para 0, woman was referred for termination of the pregnancy at 17 weeks of gestation because of the abnormal ultrasound finding of alobar HPE. The pregnancy was subsequently terminated, and a 118-g malformed male fetus was delivered with cyclopia, bilateral postaxial polydactyly of the hands and ruptured omphalocele. Postmortem cell culture of the placental tissue and umbilical cord was not successful. The parental karyotypes were normal. QF-PCR analysis using the polymorphic DNA markers of D13S1810, D13S790 and D13S251 on the DNA extracted from placenta, umbilical cord and parental bloods showed trisomy 13 of maternal origin.
CONCLUSIONS: Perinatal diagnosis of concomitant HPE, polydactyly and omphalocele should raise a suspicion of fetal trisomy 13. QF-PCR analysis is useful for rapid confirmation of trisomy 13 and the parental origin especially under the circumstance of cell culture failure, and the information acquired is very useful for genetic counseling of the parents.

OBJECTIVE: We present rapid diagnosis of trisomy 13 of maternal origin by quantitative fluorescent polymerase chain reaction (QF-PCR) in a pregnancy with multiple fetal abnormalities.
METHODS: A 35-year-old, primigravid woman was referred for amniocentesis at 24 weeks of gestation because of multiple congenital anomalies in the fetus. Prenatal ultrasound at 23 weeks of gestation revealed holoprosencephaly, premaxillary agenesis, postaxial polydactyly of the left hand and overriding aorta. Amniocentesis was performed subsequently, and QF-PCR analysis using the polymorphic DNA markers of D13S789 (13q22.3), D13S790 (13q31.1) and D13S767 (13q31.3) on the DNA extracted from uncultured amniocytes and parental bloods showed trisomy 13 of maternal origin. Conventional cytogenetic analysis on the cultured amniocytes confirmed trisomy 13. The pregnancy was subsequently terminated, and a malformed fetus was delivered with multiple anomalies consistent with the prenatal diagnosis.
CONCLUSIONS: QF-PCR analysis is useful for rapid confirmation of trisomy 13 and the parental origin when prenatal ultrasound findings are suspicious of fetal trisomy 13.

OBJECTIVE: We 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.
METHODS: A 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.
CONCLUSIONS: QF-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.

OBJECTIVE: We present detection of paternal origin of fetal trisomy 21 in a pregnancy with isolated ventriculomegaly but without advanced parental age.
METHODS: A 29-year-old pregnant woman was admitted to the hospital at 18 weeks of gestation for tocolytic treatment because of irregular uterine contractions. Her husband was 30 years old. The couple had a healthy daughter. Prenatal ultrasound incidentally found isolated ventriculomegaly, and subsequent amniocentesis revealed a karyotype of 47,XX,+21 in 20/20 colonies of cultured amniocytes. The pregnancy was terminated, and the fetus manifested characteristic craniofacial appearance of Down syndrome and hyposplastic middle phalanx of the fifth finger. Postnatal polymorphic DNA marker analysis on the DNAs extracted from the cord blood and parental bloods using quantitative fluorescent polymerase chain reaction (QF-PCR) showed a paternal origin of fetal trisomy 21. The father had a karyotype of 46, XY in 40/40 blood lymphocytes.
CONCLUSIONS: QF-PCR is useful for rapid confirmation of prenatally detected fetal trisomy 21 and determination of paternal origin of fetal trisomy 21 especially in pregnancies with fetal structural abnormalities but without advanced parental age.

OBJECTIVE: To present the prenatal diagnosis and molecular cytogenetic characterization of a de novo unbalanced reciprocal translocation.
METHODS: A 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.
CONCLUSIONS: The aCGH and QF-PCR analyses helped in delineating the genomic imbalance and parental origin of prenatally detected de novo unbalanced reciprocal translocation.

OBJECTIVE: This paper aims to present molecular cytogenetic and epigenetic evaluation of placental mesenchymal dysplasia (PMD).
METHODS: A 33-year-old woman was referred to the hospital at 18 weeks of gestation because of a multicystic mass in the placenta. Ultrasound showed a normal amount of amniotic fluid and a normal singleton fetus. Amniocentesis revealed a karyotype of 46,XX. Array comparative genomic hybridization analysis of amniocytes revealed no genomic imbalance. Preterm labor and premature rupture of the membranes occurred, and a female fetus was delivered with no structural abnormality. The placenta was enlarged and filled with many grape-like vesicles. In the placental cystic mass, interphase fluorescence in situ hybridization revealed diploidy and array comparative genomic hybridization revealed no genomic imbalance. Quantitative fluorescent polymerase chain reaction (QF-PCR), methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA), and methylation-specific PCR were performed in the placental cystic mass.
RESULTS: MS-MLPA analysis showed hypermethylation (methylation index = 0.8) at H19 differentially methylated region (DMR) [imprinting center 1 (IC1)] at 11p15.5 and hypomethylation (methylation index = 0.2) at KvDMR1(IC2) at 11p15.5. Methylation-specific PCR assay identified hypomethylation of PEG1/MEST at 7q32, and hypermethylation at H19DMR and hypomethylation at KvDMR1 at 11p15.5. QF-PCR analysis identified androgenetic/biparental mosaicism in the placenta. The placental cystic mass was consistent with the diagnosis of PMD.
CONCLUSIONS: MS-MLPA and methylation-specific PCR are useful methods for rapid detection of epigenetic alternations in PMD, and QF-PCR is useful in the diagnosis of androgenetic/biparental mosaicism.

We present prenatal diagnosis and array comparative genomic hybridization characterization of 3q26.31-q29 duplication and 9q34.3 microdeletion in a fetus with omphalocele, ventricular septal defect, increased nuchal translucency, abnormal first-trimester maternal screening and facial dysmorphism with distinct features of the 3q duplication syndrome and Kleefstra syndrome. The 26.61-Mb duplication of 3q26.31-q29 encompasses EPHB3, CLDN1 and CLDN16, and the 972-kb deletion of 9q34.3 encompasses EHMT1. We review the literature of partial trisomy 3q associated with omphalocele and discuss the genotype-phenotype correlation in this case.