Prenatal diagnosis of rearrangements in the fetal 22q11.2 region

Suping Li,Liping Wu,Ping Tang,Jinhua Dong,Yuxia Jin,Chiyan Zhou,Jie Chen,Huaxiang Shen,Jing Yang,Li Yang

doi:10.1186/s13039-020-00498-y

Suping Li, Liping Wu + Show 8 more

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https://doi.org/10.1186/s13039-020-00498-y

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Journal: Molecular Cytogenetics	Publication Date: Jul 8, 2020
Citations: 6	License type: open-access

Affiliation: Jiaxing University

Abstract

Background22q11.2 deletion syndrome (22q11.2DS) and 22q11.2 duplication syndrome (22q11.2DupS) are the most common copy number variations in humans. The clinical phenotypes of these two syndromes are variable, and there are no large sample data on the prenatal detection rate for these two syndromes in the Chinese population.ResultsWe recruited 411 pregnant women who showed either abnormal prenatal ultrasound findings or positive prenatal BoBs™ results or who had given birth to a child with chromosomal abnormalities. SNP-array analysis and interphase FISH analysis identified five fetuses with 22q11.2 copy number variants (CNVs), three of which were 22q11.2 deletion syndrome (22q11.2DS) (3/411) and two of which were 22q11.2 duplication syndrome (22q11.2DupS). In all 5 cases of diagnosed 22q11.2 abnormalities, inheritance could not be identified because the parents did not undergo further testing.ConclusionOur case reports provide a detection rate of 22q11.2 CNVs for fetuses with prenatal diagnostic indications, and early diagnosis of these two syndromes was essential for prenatal intervention in these cases. SNP-array technology is an effective tool in the prenatal diagnosis of 22q11.2 CNVs. The prenatal diagnosis of these two syndromes is helpful for early intervention, which is of great clinical significance.

Highlights

ResultsWe recruited 411 pregnant women who showed either abnormal prenatal ultrasound findings or positive prenatal BACs on BEADSTM (BoBsTM) results or who had given birth to a child with chromosomal abnormalities
Fluorescence in situ hybridization (FISH) Fluorescence in situ hybridization analysis was performed according to the manufacturer’s instructions (Abbott Laoratories, USA) for at least 30 interphase nuclei
The prenatal positive detection rate of 22q11.2 microdeletion was 7.30 in 1000 fetuses (3/411), and the positive detection rate of 22q11.2 microduplication was 4.87 in 1000 fetuses (2/411). These figures reflect the incidence of 22q11.2 copy number variants (CNVs) high-risk populations in China

Summary

Results

Among the 411 pregnant women who showed either abnormal prenatal ultrasound findings or positive prenatal BoBsTM results or who had given birth to a child with chromosomal abnormalities, SNP-array analysis identified five fetuses with 22q11.2 copy number variants (CNVs), three of which were 22q11.2DS and two of which were 22q11.2DupS (Table 1). The three fetuses with 22q11.2DS and ultrasound abnormalities were directly diagnosed by SNP-array analysis (Fig. 1d). Prenatal fetal ultrasound scanning of P1 at 23 weeks gestational age showed tetralogy of Fallot (Fig. 2a) and left kidney collection system separation (Fig. 2b). Prenatal ultrasound of the P2 fetus suggested a water cyst in the neck (Fig. 2c), and other growth indications were within the normal range. Prenatal ultrasound of the P4 fetus did not reveal any anomalies, so the pregnant woman chose to continue the pregnancy and have a normal birth. The child is a 2-year-old girl, and physical and mental examinations did not reveal any abnormalities (height 86 cm, weight 12 kg, head circumference 48 cm, heart and lung without murmur, liver and spleen without swelling, no skeletal abnormalities, normal speech and behavior development)

Conclusion

Background

Materials and methods

Discussion