Prenatal detection of chromosomal abnormalities and copy number variants in fetuses with congenital gastrointestinal obstruction

A novel genotype-phenotype between persistent-cloaca-related VACTERL and mutations of 8p23 and 12q23.1

The mechanism underlying anorectal malformations (ARMs)-related VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, and renal and limb abnormalities) remains unclear. Copy number variation (CNV) contributed to VACTERL pathogenicity. Here, we report a novel CNV in 8p23 and 12q23.1 identified in a case of ARMs-related VACTERL association. This 12-year-old girl presented a cloaca (urethra, vagina, and rectum opening together and sharing a single tube length), an isolated kidney, and a perpetuation of the left superior vena cava at birth. Her intelligence, growth, and development were slightly lower than those of normal children of the same age. Array comparative genomic hybridization revealed a 9.6-Mb deletion in 8p23.1-23.3 and a 0.52-Mb duplication in 12q23.1 in her genome. Furthermore, we reviewed the cases involving CNVs in patients with VACTERL, 8p23 deletion, and 12q23.1 duplication, and our case was the first displaying ARMs-related VACTERL association with CNV in 8p23 and 12q23.1. These findings enriched our understanding between VACTERL association and the mutations of 8p23 deletion and 12q23.1 duplication. IMPACT: This is a novel case of a Chinese girl with anorectal malformations (ARMs)-related VACTERL with an 8p23.1-23.3 deletion and 12q23.1 duplication. Cloaca malformation is presented with novel copy number variation in 8p23.1-23.3 deletion and 12q23.1 duplication.

Fetal congenital gastrointestinal obstruction: prenatal diagnosis of chromosome microarray analysis and pregnancy outcomes

OBJECTIVE

The aim of this study was to investigate the incidence of chromosome anomalies in different types of congenital gastrointestinal obstruction and assess pregnancy outcomes of fetuses with congenital gastrointestinal obstruction.

METHODS

A total of 64 cases with gastrointestinal obstruction between January 2014 and December 2020 were enrolled in this study. They were divided into three groups according to sonographic images. Group A: isolated upper gastrointestinal obstruction; Group B: isolated lower gastrointestinal obstruction; Group C: non-isolated gastrointestinal obstruction. The rate of chromosome anomalies in different groups was calculated. Pregnant women with amniocentesis were followed up by medical records and telephone. The follow-up included pregnancy outcomes and development of the live born infants.

RESULT

From January 2014 to December 2020, there were 64 fetus with congenital gastrointestinal obstruction underwent chromosome microarray analysis(CMA), the overall detection rate of CMA testing was 14.1%(9/64). The detection rate of Group A, B and C were 16.2%, 0 and 25.0% respectively. 9 fetuses with abnormal CMA results were all terminated. Among 55 fetuses with normal chromosomes, 10(18.2%) fetuses were not found to have any gastrointestinal obstruction after birth. 17(30.9%) fetuses were diagnosed with gastrointestinal obstruction and underwent surgical treatment after birth, one of which had lower gastrointestinal obstruction combined with biliary obstruction and died due to liver cirrhosis. 11(20.0%) pregnancy were terminated due to multiple abnormalities. 5(9.1%) fetuses were intrauterine death. 3(5.5%) fetuses were neonatal deaths. 9(16.4%) fetuses were lost to follow-up.

CONCLUSION

It is crucial to understand whether the gastrointestinal tract abnormality is isolated or associated to other findings. The risk of chromosomal abnormalities in fetuses with isolated lower gastrointestinal obstruction is lower than upper gastrointestinal obstruction. While genetic abnormalities excluded, a promising prognosis is expected for fetuses with congenital gastrointestinal obstruction.

Additional diagnostic value of CNV-seq over conventional karyotyping in prenatal diagnosis: A systematic review and meta-analysis

OBJECTIVE

To identify the additional diagnostic value of CNV-seq over conventional karyotyping on the part of chromosomal abnormalities in prenatal diagnosis.

METHOD

This was a systematic review conducted in accordance with PRISMA criteria. In order to clarify related research, PubMed, Web of Science databases (including Core Collection, BIOSIS Previews, MEDLINE, and so on), The Cochrane Library and Wiley Online Library were searched with the terms: "prenatal diagnosis," "CNV-seq," "karyotyping," published from January 2010 to May 2022. No language restrictions. RenMan 5.4 was used for the meta-analysis.

RESULTS

Eight studies were included in this systemic review and meta-analysis, including 11 091 pregnant women with high-risk pregnancy factors or with structurally abnormal fetus under ultrasound. CNV-seq detected a 2% (95% CI, -0% to 4%) additional chromosomal anomalies over conventional karyotyping in the six series. A 4% (95% CI, 3%-6%) pooled mean incremental yield of pathogenic CNVs by CNV-seq over karyotyping was observed, with a 1%-16% range.

CONCLUSION

CNV-seq, applied in prenatal diagnosis, may detect more chromosomal abnormalities when compared with karyotyping. With the advantages of wide coverage, high throughput, high resolution, no culture, good compatibility, and adjustable sequencing depth, CNV-seq has high application value in prenatal diagnosis.

Chromosomal Abnormalities and Pregnancy Outcomes for Fetuses With Gastrointestinal Tract Obstructions

Fetal gastrointestinal tract obstruction (GITO) is the most frequently encountered gastrointestinal defect in the prenatal period. This study aimed to investigate the genetic disorders and pregnancy outcomes of fetal GITO. We reviewed data from 70 pregnancies that were referred for invasive prenatal testing because of fetal GITO. According to the level of obstruction, they were classified into esophageal atresia/stenosis, duodenal atresia/stenosis, jejunal or ileal atresia/stenosis, or anal atresia. Traditional karyotyping was performed on all the 70 pregnancies, and chromosomal microarray analysis (CMA) was performed on 32 of them in parallel. Traditional karyotyping revealed twelve (17.1%) chromosomal abnormalities, including 11 cases of trisomy 21 (Down syndrome), and one case of a supernumerary marker chromosome related to Cat eye syndrome. According to the absence or presence of other ultrasound anomalies, they were categorized into isolated GITO (n = 36) and non-isolated GITO (n = 34). The rate of chromosomal abnormalities in the non-isolated GITO pregnancies was significantly higher than that in the isolated GITO pregnancies (29.4 vs. 5.5%, p < 0.05); the survival rate in the isolated group was significantly higher than that in the non-isolated group (67.6 vs. 34.4%, p < 0.05). Among the 32 cases where CMA was performed, an additional one (3.1%) copy number variant with clinical significance was noted in a fetus with normal karyotype. The microduplication on 7q12 was considered to be the genetic etiology of duodenal stenosis, although it was inherited from a phenotypically normal mother. Our study supports the strong association between Down syndrome and fetal GITO, especially duodenal stenosis. Our findings suggested that the risk of chromosomal abnormalities was increased when GITO was accompanied by other ultrasound anomalies; thus, chromosomal abnormalities and fetal anatomy should be carefully evaluated for pregnancy management of fetal GITO.