Chromosomal microarray analysis in the prenatal diagnosis of orofacial clefts: Experience from a single medical center in mainland China

Prenatal Diagnosis and Pregnancy Outcomes of Fetuses With Orofacial Cleft: A Retrospective Cohort Study in Two Centres in Hong Kong

OBJECTIVE

To evaluate the local incidence of orofacial cleft (OFC) encountered in fetal morphology scan and prenatal diagnosis, genetic etiology of fetuses with or without other structural abnormalities, and their pregnancy outcomes.

DESIGN

Retrospective cohort study.

SETTING

Two maternal fetal medicine units, tertiary hospitals, Hong Kong.

PARTICIPANTS

All pregnant women with antenatal diagnosis of fetal OFC between January 2016 and December 2020 (N = 66).

RESULTS

OFC has an incidence of 0.13% among pregnancies in Hong Kong and 28.8% (19/66) were syndromic cleft that exhibited other fetal structural anomalies. There were 55 cases (84.6%) who opted for invasive prenatal diagnostic testing. Genetic defects were identified in 25.8% (17/66) of this cohort, including 14 pathogenic variants. The detection rate in the syndromic cases is 68.4% (13/19) which was significantly higher than 8.5% (4/47) among non-syndromic cases. Aneuploidies would be the most common cause, accounting for 9.1% (6/66). Chromosomal microarray analysis (CMA) provided an incremental diagnostic yield of 6.1% compared to conventional karyotyping. A total of 29 live births including 3 cases of a variant of uncertain significance and 26 cases without genetic abnormalities detected have continued pregnancy to birth. There were 87.5% (21/24) without detectable pathogenic genetic abnormality reported good long-term outcomes. The chance of OFC fetuses having a good long-term outcome was significantly higher if no genomic variant was detected (P < .001).

CONCLUSIONS

Invasive prenatal tests with CMA should be offered to pregnancies with OFC regardless of the type. It has provided incremental diagnostic yield over conventional karyotyping and helped in prenatal and genetic counseling. A negative result in non-syndromic OFC favors couples to keep the pregnancy.

Exome sequencing improves genetic diagnosis of congenital orofacial clefts

Objective: This retrospective study aims to evaluate the utility of exome sequencing (ES) in identifying genetic causes of congenital orofacial clefts (OFCs) in fetuses with or without other structural abnormalities, and to further explore congenital OFCs genetic causes. Methods: The study enrolled 107 singleton pregnancies diagnosed with fetal OFCs between January 2016 and May 2022, and categorized them into two groups: isolated cleft lip and/or palate (CL/CP) and syndromic CL/CP. Cases with positive karyotyping and chromosomal microarray analysis results were excluded. Whole-exome sequencing was performed on eligible fetuses and their parents. Monogenic variants identified by ES and perinatal outcomes were recorded and evaluated during postnatal follow-up. Results: Clinically significant variants were identified in 11.2% (12/107) of fetuses, with no significant difference in detection rate between the isolated CL/CP group and the syndromic CL/CP group (8/83, 9.6% vs. 4/24, 16.7%, p = 0.553). Additionally, sixteen (16/107, 15.0%) fetuses had variants of uncertain significance. We identified 12 clinically significant variations that correlated with clinical phenotypes in 11 genes from 12 fetuses, with CHD7 being the most frequently implicated gene (n = 2). Furthermore, we observed a significant difference in termination rates and survival rates between the isolated CL/CP and syndromic CL/CP groups (41.0% vs. 70.8% and 56.6% vs. 20.8%, p < 0.05 for both). Conclusion: Based on our findings, it is clear that ES provides a significant increase in diagnostic yield for the molecular diagnosis of congenital OFCs, thereby substantially improving the existing prenatal diagnostic capabilities. This study also sheds light on seven novel pathogenic variants, broadening our understanding of the genetic underpinnings of OFCs and expanding the disease spectrums of relevant genes.

Understanding the distinction between cleft lip and cleft palate: a critical step for successful prenatal detection

PURPOSE OF REVIEW

Orofacial clefts (OCs) are among the most common congenital anomalies, however, prenatal detection of cleft palate without cleft lip (CP) remains low. CP is associated with a higher risk of associated structural anomalies, recurrence risk and genetic aberrations. There is opportunity to optimize prenatal diagnosis, counseling and diagnostic genetic testing for OCs.

RECENT FINDINGS

Improving prenatal diagnosis of CP requires understanding that embryologically, the secondary palate develops from the 6th to the 10th week and fuses with the primary palate by the 12th week. Multiple first, second and third trimester 2D ultrasonographic markers for OCs have been described including the maxillary gap, frontal space, maxilla-nasion-mandible angle, retronasal triangle, palatino-maxillary diameter, equal sign, nonvisualization or gap in the soft to hard palate interface and loss of the superimposed line. We discuss the technique, evidence and limitations of each.

SUMMARY

Prenatal detection of OC can be optimized by employing 2D sonographic markers. Prenatal detection of CP may be improved by recognizing its high association with retrognathia/micrognathia.

Cleft Lip and/or Cleft Palate: Prenatal Accuracy, Postnatal Course, and Long-Term Outcomes

Orofacial clefts include cleft lip (CL) and cleft palate (CP). This retrospective study assessed the efficacy of prenatal sonographic diagnosis of isolated and non-isolated cases of CL/CP and the postnatal outcomes of these children. Data regarding patients diagnosed and treated in the tertiary orofacial clinic from 2000 to 2020 were retrieved from electronic medical records and telephone-based questionnaires. Isolated CL was found in 7 cases (7.2%), isolated CP in 51 (53%), and combined CL/CP in 38 (39.5%), and 22 cases (23%) were associated with other anomalies. Among 96 cases, 39 (40.6%) were diagnosed prenatally. Isolated CL was diagnosed in 5/7 (71.5%), combined clefts in 29/38 (76.3%), and CP in 7/51 (13.8%). Prenatal chromosomal analysis performed in 32/39 (82%) cases was normal for all. The rate of surgical intervention in the first year of life was 36/38 (94.7%) for combined clefts, 5/7 (71.4%) for CL, and 20/51 (39%) for isolated CP. Most children had speech therapy (23/38 (60.5%), 3/7 (42.8%), and 41/51 (80.3%), respectively) and psychotherapy (6/38 (15.7%), 3/7 (42.8%) and, 15/51 (29.4%), respectively). The accuracy rate of sonographic prenatal diagnosis is low. Our results emphasize the suggested work-up of fetuses with CL and/or CP and improvements to parental counseling, as well as their understanding and compliance regarding post-natal therapeutic plans.

Molecular Approaches in Fetal Malformations, Dynamic Anomalies and Soft Markers: Diagnostic Rates and Challenges-Systematic Review of the Literature and Meta-Analysis

Fetal malformations occur in 2-3% of pregnancies. They require invasive procedures for cytogenetics and molecular testing. "Structural anomalies" include non-transient anatomic alterations. "Soft markers" are often transient minor ultrasound findings. Anomalies not fitting these definitions are categorized as "dynamic". This meta-analysis aims to evaluate the diagnostic yield and the rates of variants of uncertain significance (VUSs) in fetuses undergoing molecular testing (chromosomal microarray (CMA), exome sequencing (ES), genome sequencing (WGS)) due to ultrasound findings. The CMA diagnostic yield was 2.15% in single soft markers (vs. 0.79% baseline risk), 3.44% in multiple soft markers, 3.66% in single structural anomalies and 8.57% in multiple structural anomalies. Rates for specific subcategories vary significantly. ES showed a diagnostic rate of 19.47%, reaching 27.47% in multiple structural anomalies. WGS data did not allow meta-analysis. In fetal structural anomalies, CMA is a first-tier test, but should be integrated with karyotype and parental segregations. In this class of fetuses, ES presents a very high incremental yield, with a significant VUSs burden, so we encourage its use in selected cases. Soft markers present heterogeneous CMA results from each other, some of them with risks comparable to structural anomalies, and would benefit from molecular analysis. The diagnostic rate of multiple soft markers poses a solid indication to CMA.

The application of three-dimensional ultrasound with reformatting technique in the diagnosis of fetal cleft lip/palate

OBJECTIVE

To evaluate the clinical value of three-dimensional ultrasound (3D-US) with reformatting technique in the diagnosis of fetal cleft lip/palate (CL/P), especially those involving the secondary palate.

METHODS

A total of 113 fetuses suspected with cleft lip (CL) on two-dimensional ultrasound (2D-US) were further evaluated by 2D-US and 3D-US with reformatting technique, in order to clarify the type of oral cleft. Lesions were classified as cleft lip (CL), cleft lip and alveolus (CLA), and cleft lip and palate (CLP) (including primary and secondary palate). All fetuses were followed until birth or termination of pregnancy. The diagnostic accuracies of 2D-US and 3D-US with reformatting technology were compared.

RESULTS

Both 2D-US and 3D-US with reformatting successfully detected CLs in the final 103 participants. Among these, 29, 25, and 49 cases were confirmed to have CL, CLA, and CLP, respectively. CL, CLA, and CLP were diagnosed by 2D-US in 34, 66, and 3 cases, respectively, and by 3D-US with reformatting technology in 31, 27, and 45 cases, respectively. The sensitivities of 2D-US and 3D-US with reformatting technology in the diagnosis of CLA were 80% (20/25) and 92.0% (23/25), respectively, and the difference was not statistically significant. For CLP, however, the sensitivities were 6.1% (3/49) and 91.8% (45/49), respectively (P < .001).

CONCLUSIONS

Both 2D-US and 3D-US with reformatting technique have high diagnostic accuracy for CL and CLA. However, 3D-US has a much higher diagnostic accuracy for CLP.

Identification of genomic imbalances in oral clefts

OBJECTIVE

This article presents a clinical and cytogenomic approach that focuses on the diagnosis of syndromic oral clefts (OCs).

METHODS

The inclusion criteria were individuals with OC presenting four or more minor signs and no major defects (non-syndromic oral clefts [NSOCs]) as well as individuals with OC presenting at least another major defect, regardless of the number of minor signs (syndromic oral clefts [SOCs]). The exclusion criteria included NSOC with less than four minor signs, SOC with known etiology, as well as atypical oral clefts.

RESULTS

Of 1647 individuals with OC recorded in the Brazilian Database of Craniofacial Anomalies, 100 individuals were selected for chromosome microarray analysis (CMA). Among these, 44 individuals were clinically classified as NSOC and 56 as SOC. CMA was performed for both groups, and abnormal CMA was identified in 9%, all previously classified as SCO. The clinical and CMA data analyses showed a significant predominance of abnormal CMA in individuals classified as SOC (p = 0.0044); prematurity, weight, length, and head circumference at birth were significantly lower in the group with abnormal CMA. Besides, minor signs were significantly higher in this group (p = 0.0090).

CONCLUSION

The rigorous selection of cases indicates that the significant variables could help in early recognition of SOC. This study reinforces the importance of applying the CMA technique to establish the diagnosis of SOC. This is an important and universal issue in clinical practice for intervention, care, and genetic counseling.