Prenatal phenotype of 22q11 micro-duplications: A systematic review and report on 12 new cases

The 22q11 region is prone to generating recurring Copy Number Variations (CNVs) as a result of the large numbers of Low Copy Repeats (LCRs). Typical duplications encompass the LCR-A-to-D region but atypical duplications of various sizes have also been reported. These duplications are responsible for highly variable phenotypes with incomplete penetrance and expressivity, which is challenging for adequate genetic counselling, especially in the prenatal period. To better delineate prenatal phenotypes associated with these CNVs, we report here a clinical and molecular description of twelve cases (9 foetuses and 3 deceased new-borns babies) carrying recurrent 22q11 duplications (diagnosed via aCGH), along with a review of the existing literature. 22q11 duplications were inherited from an apparently healthy parent in almost 60% of the cases. Other CNVs were diagnosed for 8% of the cases. Increased nuchal translucency and cardiac anomalies (CHD) were the most prominent phenotypes observed, along with mild renal and skeletal anomalies. Duplications encompassing the LCR-C-to-D region (and the CRKL gene) seemed more likely to generate CHDs and renal malformations. Cleft lip/palate were observed in foetuses with duplications encompassing the LCR-A-to-B region or the SPECC1L gene, as previously suggested. However, genotype-phenotype correlations remain difficult to ascertain. Second-hit point variants, epigenetic or environmental variations could play a role in the phenotypic variability of 22q11 duplications, but remain a challenge for assessment in the short period of pregnancy.

Predicting the risk of respiratory distress in newborns with congenital pulmonary malformations

OBJECTIVES

Most children with prenatally diagnosed congenital pulmonary malformations (CPM) are asymptomatic at birth. We aimed to develop a parsimonious prognostic model for predicting the risk of neonatal respiratory distress (NRD) in preterm and term infants with CPM, based on the prenatal attributes of the malformation.

METHODS

MALFPULM is a prospective population-based nationally representative cohort including 436 pregnant women. The main predictive variable was the CPM volume ratio (CVR) measured at diagnosis (CVR first) and the highest CVR measured (CVR max). Separate models were estimated for preterm and term infants and were validated by bootstrapping.

RESULTS

In total, 67 of the 383 neonates studied (17%) had NRD. For infants born at term (>37 weeks, N=351), the most parsimonious model included CVR max as the only predictive variable (ROC area: 0.70±0.04, negative predictive value: 0.91). The probability of NRD increased linearly with increasing CVR max and remained below 10% for CVR max<0.4. In preterm infants (N=32), both CVR max and gestational age were important predictors of the risk of NRD (ROC area: 0.85±0.07). Models based on CVR first had a similar predictive ability.

CONCLUSIONS

Predictive models based exclusively on CVR measurements had a high negative predictive value in infants born at term. Our study results could contribute to the individualised general risk assessment to guide decisions about the need for newborns with prenatally diagnosed CPM to be delivered at specialised centers.

Multicolor-FISH Characterization of a Prenatal Mosaicism for a Chromosomal Rearrangement Undetected by Molecular Cytogenetics

Fetal mosaicism for chromosomal rearrangements remains a challenge to diagnose, even in the era of whole-genome sequencing. We present here a case of fetal mosaicism for a chromosomal rearrangement explored in amniocytes and fetal muscle, consisting of a major cell population (95%) with partial monosomy 4q and a minor population (5%) with additional material replacing the 4qter deleted segment. Molecular techniques (MLPA, array-CGH) failed to assess the origin of this material. Only multicolor-FISH identified the additional segment on chromosome 4 as derived from chromosome 17. Due to the poor prognosis, the couple chose to terminate the pregnancy. Because of low-level mosaicism, chromosomal microarray analysis (CMA), now considered as first-tier prenatal genetic analysis, did not allow the identification of the minor cell line. In case of large CNVs (>5 Mb) detected by CMA, karyotyping may be considered to elucidate the mechanism of the underlying rearrangement and eliminate mosaicism.

Antenatal Management of Bronchopulmonary Sequestration by Intrafetal Vascular Laser Ablation under Ultrasound Control: Narrative Review of the Literature and Report of Three Cases

OBJECTIVE

The objective of this study is to assess the effectiveness and safety of intrafetal vascular laser ablation (VLA) for fetuses with bronchopulmonary sequestration (BPS) with hydrops.

METHODS

First, we present 3 cases of fetuses with BPS and hydrops treated by VLA. Second, we aimed to conduct a narrative review to identify all reported cases of fetuses with BPS treated by intrafetal VLA.

RESULTS

The review of the literature identified 41 fetuses treated by VLA for BPS with hydrops. The median gestational age of the VLA was 27+0 weeks' gestation [25+0-31+0] with an associated procedure at the same time in 43% of the cases (pleuroamniotic shunt, thoracentesis, and amniodrainage). A second procedure was required in 25% of cases for residual flow in the feeding vessel. No stillbirth or neonatal death was reported. The complications reported were a fetal thoracic hematoma complicated by fetal anemia and 4 preterm deliveries with a rate of 9%.

CONCLUSION

VLA of the feeding vessel can be an effective treatment but is not without complications. In cases demonstrating cardiac output failure, intrafetal VLA should be considered as a treatment for BPS.

Is laterality of congenital diaphragmatic hernia a reliable prognostic factor? French national cohort study

OBJECTIVES

The objective of this study was to assess whether the laterality of congenital diaphragmatic hernia (CDH) was a prognostic factor for neonatal survival.

METHODS

This was a cohort study using the French national database of the Reference Center for Diaphragmatic Hernias. The principal endpoint was survival after hospitalization in intensive care. We made a comparative study between right CDH and left CDH by univariate and multivariate analysis. Terminations and stillbirths were excluded from analyses of neonatal outcomes.

RESULTS

A total of 506 CDH were included with 67 (13%) right CDH and 439 left CDH (87%). Rate of survival was 49% for right CDH and 74% for left CDH (P < .01). Multivariate analysis showed two factors significantly associated with mortality: thoracic herniation of liver (OR 2.27; IC 95% [1.07-4.76]; P = .03) and lung-to-head-ratio over under expected (OR 2.99; IC 95% [1.41-6.36]; P < .01). Side of CDH was not significantly associated with mortality (OR 1.87; IC 95% [0.61-5.51], P = .26).

CONCLUSION

Rate of right CDH mortality is more important than left CDH. Nevertheless after adjusting for lung-to-head-ratio and thoracic herniation of liver, right CDH does not have a higher risk of mortality than left CDH.