Clinical utility of expanded non-invasive prenatal screening compared with chromosomal microarray analysis in over 8000 pregnancies without major structural anomaly

OBJECTIVES

To evaluate the theoretical added value of two types of non-invasive prenatal screening (NIPS) expansions in pregnancies without major structural anomalies over the commonly used NIPS for chromosomes 13, 18, 21, X and Y (5-NIPS) and to compare them with the added value of chromosomal microarray analysis (CMA).

METHODS

This was a retrospective cohort study based on CMA results of all pregnancies with normal ultrasound (including pregnancies with soft markers and with abnormal maternal serum screening) that had undergone amniocentesis between January 2013 to February 2022 and were registered in the database of the Rabin Medical Center genetic laboratory. We calculated the theoretical yield of 5-NIPS and compared the added value of expanded 5-NIPS for common microdeletions (1p36.3-1p36.2, 4p16.3-4p16.2, 5p15.3-5p15.1, 15q11.2-15q13.1 and 22q11.2) and genome-wide NIPS (including variants > 5 Mb) with the added value of CMA in the overall cohort and in subgroups according to indication for invasive testing.

RESULTS

Among the 8605 examined pregnancies, 122 (1.4%) clinically significant CMA results were demonstrated. Of these, 44 (36.1%) were theoretically detectable on 5-NIPS, with the rates of 1.56% in 642 pregnancies with abnormal maternal serum screening, 0.63% in 318 pregnancies with soft markers, 0.62% in 4378 women with advanced maternal age (≥ 35 years) and 0.15% in 3267 women younger than 35 years. In addition to aneuploidies detectable on 5-NIPS, three (0.03%) cases detectable on 5-NIPS expanded for common microdeletions and nine (0.10%) cases detectable on genome-wide NIPS (excluding common microdeletions) were identified in the overall cohort. The added value of expanded NIPS tools over 5-NIPS was significantly lower compared with that of CMA, for the overall cohort and subgroups.

CONCLUSIONS

5-NIPS and even genome-wide NIPS would miss 63.9% and 54.1% of clinically significant CMA findings, respectively. The added value of 5-NIPS expanded to detect common microdeletions over 5-NIPS is about 0.035%, and the overall added value of genome-wide NIPS aimed at large CNVs is about 0.14%, both much lower compared with the added value of CMA (0.91%). These findings should assist healthcare practitioners in guiding couples towards informed decision-making regarding the choice between prenatal invasive testing and NIPS. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Microarray analysis has no additional value in fetal aberrant right subclavian artery: description of 268 pregnancies and systematic literature review

OBJECTIVES

Fetal aberrant right subclavian artery (ARSA) is a relatively common sonographic finding. Several studies have reported a significant association between ARSA and Down syndrome, as well as 22q11.2 microdeletion. The objective of this study was to assess the risk of abnormal chromosomal microarray analysis (CMA) findings in a large cohort of pregnancies with fetal ARSA as an isolated, as well as a non-isolated, sonographic anomaly. A secondary objective was to review the literature, examining the frequency of chromosomal microarray aberrations in fetuses with isolated ARSA.

METHODS

Data from all pregnancies referred for invasive testing and CMA due to sonographic diagnosis of fetal ARSA, between 2013 and 2017, were obtained retrospectively from the computerized database of the Israeli Ministry of Health. The rate of clinically significant CMA findings in these fetuses was compared to that in a local control population of 2752 low-risk pregnancies with normal ultrasound and serum screening results. In addition, a literature search was conducted in PubMed, from inception to February 2018, of original studies in the English language describing the frequency and nature of microscopic and submicroscopic aberrations in fetuses with isolated ARSA.

RESULTS

Of 246 pregnancies with isolated ARSA that underwent CMA analysis, a clinically significant finding was detected in one (0.4%) pregnancy (trisomy 21). This rate did not differ significantly from that in the control population (P = 0.1574). Of 22 fetuses with non-isolated ARSA, one (4.5%) additional case of trisomy 21 was noted. The frequency of trisomy 21 in this cohort also did not differ from that in the control population (relative risk, 5.5 (95% CI, 0.8-37.6)). The literature search yielded 13 additional relevant papers, encompassing 333 cases of isolated ARSA. Of 579 cases overall (including those of the present study), 13 (2.2%) cases of trisomy 21 were detected, with no cases of 22q11.2 microdeletion.

CONCLUSION

While an association may exist between non-isolated ARSA and Down syndrome, isolated ARSA might better serve as a soft marker for Down syndrome, rather than a routine indication for invasive prenatal testing. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cut-off value of nuchal translucency as indication for chromosomal microarray analysis

OBJECTIVES

An association between isolated, increased nuchal translucency thickness (NT) and pathogenic findings on chromosomal microarray analysis (CMA) has been reported. A recent meta-analysis reported that most studies use a NT cut-off value of 3.5 mm. However, considering NT distribution and the commonly accepted 5% false-positive rate in maternal serum screening, NT cut-off levels should be reconsidered. The aim of this study was to assess different NT cut-off levels as indication for CMA and to determine whether CMA should be recommended for mildly increased NT of 3.0-3.4 mm.

METHODS

This was a retrospective, multicenter study of singleton pregnancies with CMA results and either normal NT and no other finding or with increased NT as the only medical indication for CMA at the time of an invasive procedure (increased NT was considered an isolated finding in cases of advanced maternal age). Women with normal fetal NT who underwent CMA did so at their own request. A single laboratory performed all genetic analyses. Comparative genomic hybridization microarray analysis or single nucleotide polymorphism array technology was used for CMA. If combined first-trimester screening (NT and biochemistry) indicated increased risk for common aneuploidies, the case was excluded. NT was used to divide cases into three groups (≤ 2.9 mm, 3.0-3.4 mm and ≥ 3.5 mm) and their CMA results were compared.

RESULTS

CMA results were recorded in 1588 pregnancies, among which 770 fetuses had either normal NT with no other finding or isolated increased NT. Of these, 462 had NT ≤ 2.9 mm, 170 had NT of 3.0-3.4 mm and 138 had NT ≥ 3.5 mm. Pathogenic copy number variants were found in 1.7%, 6.5% and 13.8% of cases, respectively.

CONCLUSION

Our results suggest that CMA should be recommended when fetuses have isolated, mildly increased NT (3.0-3.4 mm). Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Homozygous deletion of RAG1, RAG2 and 5' region TRAF6 causes severe immune suppression and atypical osteopetrosis

Mutations of several genes have been implicated in autosomal recessive osteopetrosis (OP), a disease caused by impaired function and differentiation of osteoclasts. Severe combined immune deficiencies (SCID) can likewise result from different genetic mutations. We report two siblings with SCID and an atypical phenotype of OP. A biallelic microdeletion encompassing the 5' region of TRAF6, RAG1 and RAG2 genes was identified. TRAF6, a tumor necrosis factor receptor-associated family member, plays an important role in T cell signaling and in RANKL-dependent osteoclast differentiation and activation but its role in human OP has not been previously reported. The RAG proteins are essential for recombination of B and T cell receptors, and for the survival and differentiation of these cells. This is the first study to report a homozygous deletion of TRAF6 as a cause of human disease.

Chromosomal microarray analysis in fetuses with aberrant right subclavian artery

OBJECTIVE

To evaluate the association between aberrant right subclavian artery (ARSA), with or without additional risk factors for aneuploidy or ultrasound abnormality, and results of chromosomal microarray analysis (CMA).

METHODS

This was a multicenter study of fetuses diagnosed with ARSA that underwent genetic analysis by CMA, all samples being analyzed in the same laboratory. Clinical investigation included nuchal translucency measurement, first- and second-trimester maternal serum screening, early and late second-trimester fetal anatomy scans and fetal echocardiography. Comparative genomic hybridization microarray analysis or single-nucleotide polymorphism array technology was used for CMA of DNA samples obtained from amniotic fluid.

RESULTS

CMA results were available for 63 fetuses with ARSA. In 36 fetuses, ARSA was an isolated finding, and no pathogenic variant was found. Additional ultrasound findings and/or risk factors for aneuploidy were present in 27 fetuses, five of which had pathogenic CMA results. Of these five, trisomy 21 was detected in a fetus with echogenic intracardiac focus (EIF), 22q11 deletion was detected in a fetus with EIF and an increased risk of trisomy 21 of 1:230 from maternal serum screening, 22q11 duplication was detected in a fetus with hypoplastic right kidney and choroid plexus cyst and 22q11 deletion was detected in a fetus with right aortic arch and clubfoot. The fifth fetus had increased nuchal translucency thickness (4 mm) and a ventricular septal defect, and CMA identified both 22q11 deletion and 1q21 duplication.

CONCLUSIONS

In fetuses with isolated ARSA, an invasive procedure for CMA is not indicated. However, CMA is recommended when additional ultrasound abnormalities or risk factors for aneuploidy are observed. The chromosomal findings in four of the five cases with an abnormal CMA result in our study would not have been detected by standard fetal chromosomal testing. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Blood pressure variability in acute ischemic stroke depends on hemispheric stroke location

The relationship between blood pressure (BP) variability and stroke location was examined in 85 patients admitted with acute ischemic stroke. The patients were divided into three groups according to stroke location: right hemisphere (32 patients), left hemisphere (30 patients) and non-localized (23 patients). BP upon admission was 147.94/76.53 +/- 20.72/13.70 mmHg in the right hemisphere group, 151.81/76.10 +/- 25.69/16.23 mmHg in the left hemisphere and 155.23/83.41 +/- 30.45/15.74 in the non-localized group. The left hemisphere group had significantly (p < 0.01) greater variations in systolic and diastolic BP between days 2 and 3 and in systolic BP between days 3 and 4 after stroke compared with the other groups. BP in the left hemisphere group was less stable than in the other two groups. Non-localized patients without pre-existing hypertension had a significantly lower and more stable BP during the week following stroke than non-localized patients with pre-existing hypertension. Non-localized patients with pre-existing hypertension had the highest BP and showed no improvement during the week. Systolic BP tended to be higher and less stable in left hemisphere patients than in right hemisphere, whereas among non-localized ischemic stroke patients BP was higher in those who had a prior diagnosis of hypertension.