Should prenatal chromosomal microarray analysis be offered for isolated fetal growth restriction? A French multicenter study

Chromosomal Microarray Analysis in Fetuses with Ultrasound Abnormalities

Objective

To explore and evaluate the value of chromosomal microarray analysis (CMA) in prenatal diagnosis of fetuses with ultrasound abnormalities.

Methods

A retrospective analysis was performed on 370 fetuses with ultrasound abnormalities received invasive prenatal diagnosis at Meizhou People's Hospital from October 2022 to December 2023. Fetal specimens were analyzed by CMA, and the detection rates of aneuploidy and pathogenic (P)/likely pathogenic (LP) copy number variations (CNVs) in ultrasound structural abnormalities (malformations of fetal anatomy) and non-structural abnormalities (abnormalities of fetal nonanatomical structure) were analyzed.

Results

There were 114 (30.8%) cases with isolated ultrasound structural abnormalities, 226 (61.1%) cases with isolated non-structural abnormalities (182 isolated ultrasound soft markers abnormalities, 30 isolated fetal growth restriction (FGR), and 8 isolated abnormalities of amniotic fluid volume), and 30 (8.1%) cases with both structural and non-structural abnormalities. The overall detection rate of aneuploidy and P/LP CNVs in isolated ultrasonic structural abnormalities was 5.3%, among which cardiovascular system abnormalities were the highest. In addition, the largest number of fetuses with non-structural abnormalities was nuchal translucency (NT) thickening (n = 81), followed by ventriculomegaly (n = 29), and nasal bone dysplasia (n = 24). The detection rate of chromosomal abnormalities of fetuses with abnormal ultrasound soft markers was 9.9%, and the detection rate in single abnormal ultrasound soft marker, and multiple ultrasound soft markers abnormalities was 9.7% (16/165) and 11.8% (2/17), respectively. Moreover, the detection rate of chromosomal abnormalities of fetuses with FGR and structural abnormalities combined with non-structural abnormalities was 6.7% (2/30), and 13.3% (4/30), respectively.

Conclusion

The incidence of chromosomal abnormalities (aneuploidy and P/LP CNVs) varies among different fetal ultrasound abnormalities.

Antenatal ultrasound features of isolated recurrent copy number variation in 7q11.23 (Williams syndrome and 7q11.23 duplication syndrome)

OBJECTIVE

We aimed to gather fetal cases carrying a 7q11.23 copy number variation (CNV) and collect precise clinical data to broaden knowledge of antenatal features in these syndromes.

METHODS

We retrospectively recruited unrelated cases with 7q11.23 deletion, known as Williams-Beuren syndrome (WBS), or 7q11.23 duplication who had prenatal ultrasound findings. We collected laboratory and clinical data, fetal ultrasound, cardiac ultrasound and fetal autopsy reports from 18 prenatal diagnostic centers throughout France.

RESULTS

40 fetuses with WBS were collected and the most common features were intra-uterine growth retardation (IUGR) (70.0%, 28/40), cardiovascular defects (30.0%, 12/40), polyhydramnios (17.5%, 7/40) and protruding tongue (15.0%, 6/40). Fetal autopsy reports were available for 11 cases and were compared with ultrasound prenatal features. Four cases of fetuses with 7q11.23 microduplication were collected and prenatal ultrasound signs were variable and often isolated.

CONCLUSION

This work strengthens the fact that 7q11.23 CNVs are associated with a broad spectrum of antenatal presentations. IUGR and cardiovascular defects were the most frequent ultrasound signs. By reporting the biggest series of antenatal WBS, we aim to better delineate distinctive signs in fetuses with 7q11.23 CNVs.

Contribution of amniocentesis in fetuses small for gestational age without other sonographic signs

OBJECTIVE

Our study evaluated the contribution of amniocentesis in the diagnostic approach of small-for-gestational-age fetuses (SGA) without morphological abnormality identified on ultrasound by studying FISH (fluorescence in situ hybridization) for chromosomes 13, 18 and 21, CMV PCR (cytomegalovirus polymerase chain reaction), karyotype and CGH (genomic hybridization array) METHODS: Our single-center retrospective cohort study included pregnant women referred for prenatal diagnosis for a SGA fetus in whom amniocentesis was performed between 2016 and 2019. A SGA fetus was defined as a fetus with an estimated fetal weight (EFW) below the 10th percentile according to referral growth curves in use. We evaluated the number of amniocenteses with an abnormal result and identified factors that may be associated with this outcome.

RESULTS

Among the 79 amniocenteses performed, there were 5 (6.3%) abnormalities: karyotype (1.3%) and CGH (5.1%). No complications were described. We did not find any statistically significant factors associated with abnormal amniocentesis findings even if some elements seemed reassuring such as late discovery (p = 0.31), moderate SGA (p = 0.18), normal head, abdomen and femur measurements (p = 0.57), but without statistically significant difference.

CONCLUSION

Our study found 6.3% pathological analysis of amniocenteses, of which several would have been missed by conventional karyotyping. Patients must be informed about the risk of detecting abnormalities of low severity, with low penetrance or with unknown fetal consequences that could be source of anxiety.

Fetal genetic findings by chromosomal microarray analysis and karyotyping for fetal growth restriction without structural malformations at a territory referral center: 10-year experience

BACKGROUND

Prenatal invasive genetic testing is commonly recommended to pregnancies of early-onset FGR or FGR combined with a structural defect. Our study aimed to explore the genetic findings for FGR without structural malformations according to cytogenetic karyotyping and single nucleotide polymorphism array (SNP array) technology over a 10-year period.

METHODS

A total of 488 pregnancies diagnosed with FGR without structural malformation were retrospectively reviewed. Cytogenetic karyotyping was performed on all the subjects, and SNP array was available from 272 of them. Based on the gestational age at onset, the cohort was classified into four groups: ≤ 24, 25-28, 29-32, and > 32 weeks of gestation. According to the ultrasound findings, they were grouped into isolated FGR, FGR with soft markers, and FGR with non-structural anomalies. In pregnancies of young maternal age, based on the results of maternal serum screening (MSS), they were categorized into high-risk and low-risk MSS groups.

RESULTS

Nineteen (3.9%) cases of chromosomal abnormalities were detected by cytogenetic karyotyping, including 11 cases of numerical abnormalities, 5 cases of structural abnormalities, and 3 cases of mosaicism. Trisomy 21 was the most frequent abnormality. Abnormal karyotypes were more frequently observed in cases diagnosed at ≤ 24 weeks (7.2%) than those in any other group. Among pregnancies with normal karyotype, an incremental yield of 4.2% were revealed by SNP array technology regarding clinically relevant aberrations. The additional detection rates by SNP array in cases diagnosed at ≤ 24 weeks (6.5%), cases with soft markers (9.5%), and cases with high-risk MSS (12.0%) were higher than those in other groups within each classification. All the cases with abnormal karyotypes and 7 out of 11 pregnancies with clinically relevant anomalies revealed by SNP array alone resulted in pregnancy terminations.

CONCLUSION

Chromosome abnormality is an important etiology for FGR with no associated structural malformations, and plays a crucial role in pregnancies decision-making. SNP array improves the detection of genetic anomalies especially in FGR diagnosed at ≤ 24 weeks, FGR combined with soft makers, and FGR combined with high-risk MSS.

Genetics Etiologies Associated with Fetal Growth Restriction

Fetal growth restriction (FGR) is associated with multiple adverse perinatal outcomes, such as increased risk of intrauterine death, neonatal morbidity and mortality, and long-term adverse outcomes. Genetic etiological factors are critical in fetuses with intrauterine growth restriction, including chromosomal abnormalities, copy number variants, single gene disorders, uniparental disomy, epigenetic changes, and confined placental mosaicism. This paper aims to provide an overview of genetic defects related to FGR and to highlight the importance of prenatal genetic counseling and testing for precise diagnosis and management of FGR.

The Genetic and Clinical Outcomes in Fetuses With Isolated Fetal Growth Restriction: A Chinese Single-Center Retrospective Study

Objective: To evaluate the utility of a chromosomal microarray (CMA) in fetuses with isolated fetal growth restriction (FGR) and explore risk factors for the prediction of chromosomal aberration and perinatal adverse outcomes.

Method: This study included 271 fetuses of estimated fetal weight less than the 3rd percentile without other structural malformation. Early-onset and late-onset FGR were defined as gestational weeks less than 32 weeks and more than 32 weeks respectively. These patients underwent quantitative fluorescent polymerase chain reaction (QF-PCR) and CMA as the first-line genetic detection strategy. Chromosomal anomalies were compared after stratified analysis by the early-onset and the late-onset FGR, including the absence or presence of ultrasound soft markers, abnormal amniotic fluid, abnormal umbilical Doppler, and gestational disorders. The follow-up time was within 1 year after birth. Logistic regression was used to seek risk predictors of chromosomal aberration and perinatal adverse outcomes for isolated FGR.

Results: The CMA identified clinically significant variants in 18/271 (6.6%) fetuses, and variants of unknown significance (VOUS) in 15/271 (5.5%) fetuses. Stratified analysis showed that there was a higher incidence of clinically significant variants in fetuses with the early-onset FGR compared with late-onset FGR (8.7%, 17/195 vs. 1.3%, 1/76, p < 0.05). Regression analysis showed that early gestational age (GA) at diagnosis of FGR was the major risk factor for chromosomal aberration (OR = 0.846). By variable regression analysis, early GA at diagnosis and decreased estimated fetal weight (EFW) percentile of suspicion of FGR, asymmetrical FGR, abnormal amniotic fluid, and severe preeclampsia could all increase the risk of adverse outcomes of isolated FGR including intra-uterine fetal death (IUFD), termination of pregnancy (TOP), and preterm birth in pregnancies with FGR.

Conclusion: This study emphasized the value of microarrays for unbalanced genomic variants in fetuses with isolated FGR, especially since the gestational age of nullipara was less than 32 weeks. Perinatal adverse outcomes of isolated FGR were influenced by multiple factors including GA and estimated fetal weight (EFW) percentile of suspicion of FGR, asymmetrical FGR, abnormal amniotic fluid, and severe preeclampsia.

Differentially Expressed Genes Reveal the Biomarkers and Molecular Mechanism of Osteonecrosis

Osteonecrosis is one of the most refractory orthopedic diseases, which seriously threatens the health of old patients. High-throughput sequencing (HTS) and microarray analysis have confirmed as an effective way for investigating the pathological mechanism of disease. In this study, GSE7716, GSE74089, and GSE123568 were obtained from Gene Expression Omnibus (GEO) database and used to identify differentially expressed genes (DEGs) by R language. Subsequently, the DEGs were analyzed with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Moreover, the protein-protein interaction (PPI) network of DEGs was analyzed by STRING database and Cytoscape. The results showed that 318 downregulated genes and 58 upregulated genes were observed in GSE7116; 690 downregulated genes and 1148 upregulated genes were screened from 34183 genes in GSE74089. The DEGs involved in progression of osteonecrosis involved inflammation, immunological rejection, and bacterial infection-related pathways. The GO enrichment showed that osteonecrosis was related with extracellular matrix, external encapsulating structure organization, skeletal system development, immune response activity, cell apoptosis, mononuclear cell differentiation, and serine/threonine kinase activity. Moreover, PPI network showed that the progression of osteonecrosis of the femoral head was related with CCND1, CDH1, ESR1, SPP1, LOX, JUN, ITGA, ABL1, and VEGF, and osteonecrosis of the jaw is related with ACTB, CXCR4, PTPRC, IL1B, CXCL8, TNF, JUN, PTGS2, FOS, and RHOA. In conclusion, this study identified the hub factors and pathways which might play important roles in progression of osteonecrosis and could be used as potential biomarkers for diagnosis and treatment of osteonecrosis.

Highlighting the trajectory from intrauterine growth restriction to future obesity

During the last decades several lines of evidence reported the association of an adverse intrauterine environment, leading to intrauterine restriction, with future disease, such as obesity and metabolic syndrome, both leading to increased cardiovascular and cancer risk. The underlying explanation for this association has firstly been expressed by the Barker's hypothesis, the "thrifty phenotype hypothesis". According to this hypothesis, a fetus facing an adverse intrauterine environment adapts to this environment through a reprogramming of its endocrine-metabolic status, during the crucial window of developmental plasticity to save energy for survival, providing less energy and nutrients to the organs that are not essential for survival. This theory evolved to the concept of the developmental origin of health and disease (DOHaD). Thus, in the setting of an adverse, f. ex. protein restricted intrauterine environment, while the energy is mainly directed to the brain, the peripheral organs, f.ex. the muscles and the liver undergo an adaptation that is expressed through insulin resistance. The adaptation at the hepatic level predisposes to future dyslipidemia, the modifications at the vascular level to endothelial damage and future hypertension and, overall, through the insulin resistance to the development of metabolic syndrome. All these adaptations are suggested to take place through epigenetic modifications of the expression of genes without change of their amino-acid sequence. The epigenetic modifications leading to future obesity and cardiovascular risk are thought to induce appetite dysregulation, promoting food intake and adipogenesis, facilitating obesity development. The epigenetic modifications may even persist into the next generation even though the subsequent generation has not been exposed to an adverse intrauterine environment, a notion defined as the "transgenerational transfer of environmental information". As a consequence, if the increased public health burden and costs of non-communicable chronic diseases such as obesity, hypertension, metabolic syndrome and type 2 diabetes have to be minimized, special attention should be laid to the healthy lifestyle habits of women of reproductive age, including healthy diet and physical activity to be established long before any pregnancy takes place in order to provide the best conditions for both somatic and mental health of future generations.