OBJECTIVE: To analyze the prognosis of fetuses identified with de novo variants of unknown significance (VOUS) by chromosome microarray analysis (CMA). METHODS: A total of 6 826 fetuses who underwent prenatal CMA detection at the Prenatal Diagnosis Center of Drum Tower Hospital from July 2017 to December 2021 were selected as the study subjects. The results of prenatal diagnosis, and outcome of fetuses identified with VOUS of de novo origin were followed up. RESULTS: Among the 6 826 fetuses, 506 have carried VOUS, of which 237 were detected for the parent-of-origin and 24 were found to be de novo. Among the latters, 20 were followed up for 4 to 24 months. Four couples had opted elective abortion, 4 had developed clinical phenotypes after birth, and 12 were normal. CONCLUSION Fetuses with VOUS should be continuously follow-up, in particular those carrying de novo VOUS, in order to clarify their clinical significance.
Pregnancy ; Female ; Humans ; DNA Copy Number Variations ; Follow-Up Studies ; Prenatal Diagnosis/methods* ; Chromosomes ; Microarray Analysis/methods* ; Fetus ; Chromosome Aberrations

OBJECTIVE: To provide prenatal diagnosis, pedigree analysis and genetic counseling for a pregnant woman who had given birth to a child featuring global developmental delay. METHODS: A pregnant woman who underwent prenatal diagnosis at the Affiliated Hospital of Southwest Medical University in August 2021 was selected as the study subject. Peripheral blood samples were collected from the woman, her husband and child, in addition with amniotic fluid sample during mid-pregnancy. Genetic variants were detected by G-banded karyotyping analysis and copy number variation sequencing (CNV-seq). Pathogenicity of the variant was predicted based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Candidate variant was traced in the pedigree to assess the recurrence risk. RESULTS: The karyotypes of the pregnant woman, her fetus, and affected child were 46,XX,ins(18)(p11.2q21q22), 46,X?,rec(18)dup(18)(q21q22)ins(18)(p11.2q21q22)mat and 46,XY,rec(18)del(18)(q21q22)ins(18)(p11.2q21q22)mat, respectively. Her husband was found to have a normal karyotype. CNV-seq has revealed a 19.73 Mb duplication at 18q21.2-q22.3 in the fetus and a 19.77 Mb deletion at 18q21.2-q22.3 in her child. The duplication and deletion fragments were identical to the insertional fragment in the pregnant woman. Based on the ACMG guidelines, the duplication and deletion fragments were both predicted to be pathogenic. CONCLUSION The intrachromosomal insertion of 18q21.2-q22.3 carried by the pregnant woman had probably given rise to the 18q21.2-q22.3 duplication and deletion in the two offspring. Above finding has provided a basis for genetic counseling for this pedigree.
Child ; Female ; Humans ; Pregnancy ; DNA Copy Number Variations ; East Asian People ; Pedigree ; Prenatal Diagnosis/methods* ; Chromosomes, Human, Pair 18/genetics* ; Male ; Fetus ; INDEL Mutation

OBJECTIVE: To explore the genetic basis for a fetus with severe heart defect and mosaic trisomy 12, and the correlation between chromosomal abnormalities and clinical manifestations and pregnancy outcome. METHODS: A 33-year-old pregnant woman who presented at Lianyungang Maternal and Child Health Care Hospital on May 17, 2021 due to abnormal fetal heart development revealed by ultrasonography was selected as the study subject. Clinical data of the fetus were collected. Amniotic fluid sample of the pregnant women was collected and subjected to G-banded chromosomal karyotyping and chromosomal microarray analysis (CMA). The CNKI, WanFang and PubMed databases were searched with key words, with the retrieval period set as from June 1, 1992 to June 1, 2022. RESULTS: For the 33-year-old pregnant woman, ultrasonography at 22+6 gestational weeks had revealed abnormal fetal heart development and ectopic pulmonary vein drainage. G-banded karyotyping showed that the fetus has a karyotype of mos 47,XX,+12[1]/46,XX[73], with the mosaicism rate being 1.35%. CMA results suggested that about 18% of fetal chromosome 12 was trisomic. A newborn was delivered at 39 weeks of gestation. Follow-up confirmed severe congenital heart disease, small head circumference, low-set ears and auricular deformity. The infant had died 3 months later. The database search has retrieved 9 reports. Literature review suggested that the liveborn infants with mosaic trisomy 12 had diverse clinical manifestations depending on the affected organs, which had included congenital heart disease and/or other organs and facial dysmorphisms, resulting in adverse pregnancy outcomes. CONCLUSION Trisomy 12 mosaicism is an important factor for severe heart defects. The results of ultrasound examination have important value for evaluating the prognosis of the affected fetuses.
Infant, Newborn ; Child ; Pregnancy ; Female ; Humans ; Adult ; Trisomy/genetics* ; Amniocentesis/methods* ; Chromosome Disorders ; Mosaicism ; Fetus ; Heart Defects, Congenital/genetics*

OBJECTIVE: To explore the genetic basis for fetus with bilateral lateral ventriculomegaly. METHODS: Fetus umbilical cord blood and peripheral blood samples of its parents were collected. The fetus was subjected to chromosomal karyotyping, whilst the fetus and its parents were subjected to array comparative genomic hybridization (aCGH). The candidate copy number variation (CNV) were verified by qPCR, Application goldeneye DNA identification system was used to confirm the parental relationship. RESULTS: The fetus was found to have a normal karyotype. aCGH analysis indicated that it has carried a 1.16 Mb deletion at 17p13.3, which partially overlapped with the critical region of Miller-Dieker syndrome (MDS), in addition with a 1.33 Mb deletion at 17p12 region, which is associated with hereditary stress-susceptible peripheral neuropathy (HNPP). Its mother was also found to harbor the 1.33 Mb deletion at 17p12. qPCR analysis confirmed that the expression levels of genes from the 17p13.3 and 17p12 regions were about the half of that in the normal control, as well as the maternal peripheral blood sample. Parental relationship was confirmed between the fetus and its parents. Following genetic counseling, the parents has chosen to continue with the pregnancy. CONCLUSION The fetus was diagnosed with Miller-Dieker syndrome due to the de novo deletion at 17p13.3. Ventriculomegaly may be an important indicator for prenatal ultrasonography in fetuses with MDS.
Pregnancy ; Female ; Humans ; Classical Lissencephalies and Subcortical Band Heterotopias ; Comparative Genomic Hybridization ; DNA Copy Number Variations ; Fetus ; Hydrocephalus ; Prenatal Diagnosis ; Chromosome Deletion

OBJECTIVE: To analyze the result of prenatal diagnosis and outcome of pregnancy for fetuses with rare autosomal trisomies (RATs) suggested by non-invasive prenatal testing (NIPT). METHODS: A total of 69 608 pregnant women who underwent NIPT at Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2020 were selected as study subjects. The result of prenatal diagnosis and outcome of pregnancy for those with a high risk for RATs were retrospectively analyzed. RESULTS: Among the 69 608 pregnant women, the positive rate of NIPT for high-risk RATs was 0.23% (161/69 608), with trisomy 7 (17.4%, 28/161) and trisomy 8 (12.4%, 20/161) being the most common, and trisomy 17 (0.6%, 1/161) being the rarest. For 98 women who had accepted invasive prenatal diagnosis, 12 fetal chromosomal abnormalities were confirmed, and in 5 cases the results were consistent with those of NIPT, which yielded a positive predictive value of 5.26%. Among the 161 women with a high risk for RATs, 153 (95%) were successfully followed up. 139 fetuses were ultimately born, with only one being clinically abnormal. CONCLUSION Most women with a high risk for RATs by NIPT have good pregnancy outcomes. Invasive prenatal diagnosis or serial ultrasonography to monitor fetal growth, instead of direct termination of pregnancy, is recommended.
Pregnancy ; Female ; Humans ; Trisomy/genetics* ; Pregnancy Outcome ; Retrospective Studies ; Prenatal Diagnosis/methods* ; Fetus ; Trisomy 18 Syndrome/genetics* ; Aneuploidy

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) and trio-whole exome sequencing (trio-WES) for fetuses with increased nuchal translucency (NT) thickness. METHODS: Sixty two pregnant women who had visited Urumqi Maternal and Child Care Health Hospital between June 2018 and June 2020 for NT ≥ 3.0 mm at 11 ~ 13⁺⁶ gestational weeks were selected as study subjects. Relevant clinical data were collected. The patients were divided into 3.0 ~ ＜3.5 mm (n = 33) and ≥3.5 mm groups (n = 29). Chromosome karyotyping analysis and chromosomal microarray analysis were carried out. And trio-WES analysis was performed on 15 samples with NT thickening but negative CMA results. The distribution and incidence of chromosomal abnormalities in the two groups were compared by using chi-square test. RESULTS: The median age of the pregnant women was 29 years old (22 ~ 41 years old), the median thickness of NT was 3.4 mm (3.0 ~ 9.1 mm), and the median gestational age at the detection was 13⁺⁴ weeks (11⁺⁵ ~ 13⁺⁶ weeks). Chromosome karyotyping analysis has detected 12 cases of aneuploidies and 1 case of derivative chromosome. The detection rate was 20.97% (13/62). CMA has detected 12 cases of aneuploidies, 1 case of pathogenic CNV and 5 cases of variant of uncertain significance (VUS), with a detection rate of 29.03% (18/62). The aneuploidy rate for the NT ≥ 3.5 mm group was higher than that for the 3.0 ≤ NT < 3.5 mm group [3.03% (1/33) vs. 41.38% (12/29), χ² = 13.698, P < 0.001]. There was no statistically significant difference between the two groups in the detection rate of fetal pathogenic CNV and VUS (χ² = 0.028, P > 0.05). Trio-WES analysis of 15 samples with negative CMA result and no structural abnormality has identified 6 heterozygous variants, including SOS1: c.3542C>T (p.A1181V) and c.3817C>G (p.L1273V), COL2A1: c.436C>T (p.P146S) and c.3700G>A (p.D1234N), LZTR1: c.1496T>C (p.V499A), and BRAF: c.64G>A (p.D22N), respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), all of the variants were rated as VUS. CONCLUSION NT thickening can indicate chromosome abnormality, and CMA and trio-WES may be used for the prenatal diagnosis.
Pregnancy ; Humans ; Female ; Adult ; Infant ; Nuchal Translucency Measurement/methods* ; Prenatal Diagnosis/methods* ; Chromosome Aberrations ; Aneuploidy ; Fetus/diagnostic imaging* ; Ultrasonography, Prenatal ; DNA Copy Number Variations ; Transcription Factors

OBJECTIVE: To explore the genetic etiology of 5 cases of monochorionic-diamniotic (MCDA) with genetic discordance. METHODS: 148 cases of MCDA twins who were diagnosed by amniocentesis at the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region from January 2016 to June 2020 were selected as the study subjects. Relevant clinical data of the pregnant women were collected, and amniotic fluid samples of the twins were collected separately. Chromosomal karyotyping analysis and single nucleotide polymorphism array (SNP array) assay were carried out. RESULTS: The results of chromosomal karyotyping analysis showed that 5 of the MCDA twins had inconsistent chromosome karyotypes, with an incidence of 3.4% (5/148). SNP array assay showed that 3 fetuses were mosaics. CONCLUSION Genetic discordance occurs among MCDA twins, and prenatal counseling for such cases should be given by doctors with experience in medical genetics and fetal medicine, and personalized clinical management should be recommended.
Child ; Pregnancy ; Female ; Humans ; China ; Twins/genetics* ; Amniocentesis ; Karyotyping ; Fetus ; Twins, Monozygotic/genetics* ; Ultrasonography, Prenatal ; Retrospective Studies

OBJECTIVE: To explore the genetic basis for a fetus with Cardiac-urogenital syndrome (CUGS). METHODS: A fetus with congenital heart disease identified at the Maternal Fetal Medical Center for Fetal Heart Disease, Beijing Anzhen Hospital Affiliated to Capital Medical University in January 2019 was selected as the study subject. Clinical data of the fetus was collected. Copy number variation sequencing (CNV-seq) and trio-whole exome sequencing (trio-WES) were carried out for the fetus and its parents. Candidate variants were verified by Sanger sequencing. RESULTS: Detailed fetal echocardiographic examination had revealed hypoplastic aortic arch. The results of trio-WES revealed that the fetus has harbored a de novo splice variant of the MYRF gene (c.1792-2A>C), for which both parents were of the wild-type. Sanger sequencing confirmed the variant to be de novo. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic. CNV-seq has identified no chromosomal anomalies. And the fetus was diagnosed with Cardiac-urogenital syndrome. CONCLUSION The de novo splice variant of the MYRF gene probably underlay the abnormal phenotype in the fetus. Above finding has enriched the spectrum of MYRF gene variants.
Female ; Humans ; DNA Copy Number Variations ; Fetal Diseases ; Fetus/abnormalities* ; Heart Defects, Congenital/genetics* ; Mutation ; Transcription Factors/genetics*

OBJECTIVE: To explore the prenatal ultrasonographic features and genetic basis for an abortus suspected for type II Cornelia de Lange syndrome (CdLS2). METHODS: A fetus diagnosed with CdLS2 at the Shengjing Hospital Affiliated to China Medical University on September 3, 2019 was selected as the study subject. Clinical data of the fetus and family history was collected. Following induced labor, whole exome sequencing was carried out on the abortus. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Prenatal ultrasonography (33 weeks of pregnancy) has revealed multiple anomalies in the fetus, which included slightly widened cavity of septum pellucidum, blurred corpus callosum, slightly reduced frontal lobe volume, thin cortex, fusion of lateral ventricles, polyhydramnios, small stomach bubble, and digestive tract atresia. Whole exome sequencing has revealed a heterozygous c.2076delA (p.Lys692Asnfs*27) frameshifting variant in the SMC1A gene, which was found in neither parent and was rated as pathogenic based on the guidelines of American College of Medical Genetics and Genomics (ACMG). CONCLUSION The CdLS2 in this fetus may be attributed to the c.2076delA variant of the SMC1A gene. Above finding has provided a basis for genetic counseling and assessment of reproductive risk for this family.
Pregnancy ; Female ; Humans ; Cell Cycle Proteins/genetics* ; De Lange Syndrome/diagnosis* ; Phenotype ; Ultrasonography, Prenatal ; Fetus/diagnostic imaging* ; Mutation

OBJECTIVE: To explore the genetic etiology for a fetus with Walker-Warburg syndrome(WWS). METHODS: A fetus with WWS diagnosed at Gansu Provincial Maternity and Child Health Care Hospital in June 9, 2021 was selected as the study subject. Genomic DNA was extracted from amniotic fluid sample of the fetus and peripheral blood samples from its parents. Trio-Whole exome sequencing (trio-WES) was carried out. Candidate variants were verified by Sanger sequencing. RESULTS: The fetus was found to harbor compound heterozygous variants of the POMT2 gene, namely c.471delC (p.F158Lfs*42) and c.1975C>T (p.R659W), which were respectively inherited from its father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), they were respectively rated as pathogenic (PVS1+PM2_Supporting+PP4) and likely pathogenic (PM2_Supporting+PM3+PP3_Moderate+PP4). CONCLUSION Trio-WES may be used for the prenatal diagnosis of WWS. The compound heterozygous variants of the POMT2 gene probably underlay the disorder in this fetus. Above finding has expanded the mutational spectrum of the POMT2 gene and enabled definite diagnosis and genetic counseling for the family.
Pregnancy ; Child ; Female ; Humans ; Walker-Warburg Syndrome ; Prenatal Diagnosis ; Fetus ; Genetic Counseling ; Genomics ; Mutation