Diagnostic yield of whole exome data in fetuses aborted for conotruncal malformations

Diagnostic yield after next-generation sequencing in pediatric cardiovascular disease

Genetic testing with exome sequencing and genome sequencing is increasingly offered to infants and children with cardiovascular diseases. However, the rates of positive diagnoses after genetic testing within the different categories of cardiac disease and phenotypic subtypes of congenital heart disease (CHD) have been little studied. We report the diagnostic yield after next-generation sequencing in 500 patients with CHD from diverse population subgroups that were enrolled at three different sites in the Clinical Sequencing Evidence-Generating Research consortium. Patients were ascertained due to a primary cardiovascular issue comprising arrhythmia, cardiomyopathy, and/or CHD, and corresponding human phenotype ontology terms were selected to describe the cardiac and extracardiac findings. We examined the diagnostic yield for patients with arrhythmia, cardiomyopathy, and/or CHD and phenotypic subtypes of CHD comprising conotruncal defects, heterotaxy, left ventricular outflow tract obstruction, septal defects, and "other" heart defects. We found a significant increase in the frequency of positive findings for patients who underwent genome sequencing compared to exome sequencing and for syndromic cardiac defects compared to isolated cardiac defects. We also found significantly higher diagnostic rates for patients who presented with isolated cardiomyopathy compared to isolated CHD. For patients with syndromic presentations who underwent genome sequencing, there were significant differences in the numbers of positive diagnoses for phenotypic subcategories of CHD, ranging from 31.7% for septal defects to 60% for "other". Despite variation in the diagnostic yield at each site, our results support genetic testing in pediatric patients with syndromic and isolated cardiovascular issues and in all subtypes of CHD.

The evolving genetic etiology of conotruncal anomalies

OBJECTIVE

To assess the diagnostic yield of genetic testing for antenatally detected conotruncal defects.

METHOD

This was a retrospective analysis of all antenatally detected cases of conotruncal anomalies over a 4-year period. Patients were offered antenatal and postnatal genetic testing including QF-PCR, microarray and exome sequencing (ES) antenatally or genome sequencing (GS) postnatally on a case-by-case basis.

RESULTS

There were 301 cases included. Overall, there were pathogenic genetic findings in 27.6% of the cases tested (53/192). The commonest finding was 22q11.21 deletion (20/192 cases, 10.4%), followed by trisomy 21 (6/192, 3.1%). There were 249 cases of isolated conotruncal anomalies, of which 59.8% (149/249) had genetic testing and 22.8% (34/149) had pathogenic findings. ES/GS was performed in five cases with no pathogenic findings. There were 52 cases of non-isolated contruncal anomalies, of which 82.7% (43/52) had genetic testing. ES/GS was performed in 11 cases in this group and increased the yield of clinically significant diagnoses from 32.6% (14/43) to 44.2% (19/43).

CONCLUSION

Genetic abnormalities are present in over one quarter of cases of antenatally detected conotruncal anomalies. The commonest abnormality is 22q11.21 deletion. Exome sequencing or genome sequencing leads to a significant increase in genetic diagnosis in non-isolated cases.

Relationship between diagnosis of conus arteriosus malformation and genetic diagnosis results in fetal cardiac axis abnormalities by echocardiography during middle pregnancy

Objective

To explore the clinical value of echocardiography in detecting fetal cardiac axis abnormalities during middle pregnancy for diagnosing conus arteriosus malformation, and to compare and analyze the genetic diagnosis results, in order to provide evidence for clinical diagnosis and intervention.

Methods

Four hundred twenty-one fetuses with conus arteriosus malformation from January 2020 to October 2023 were included as the conus arteriosus malformation group, and 917 healthy fetuses (all single fetuses) matched at the same gestational age were selected as the healthy group.

Results

There was no significant difference in gestational weeks between two groups (P > 0.05). The age of pregnant women in conus arteriosus malformation group was lower compared to healthy group (P < 0.05), and the fetal cardiac axis in conus arteriosus malformation group was significantly higher compared to healthy group (P < 0.05). Among the fetuses with conus arteriosus malformation, tetralogy of Fallot (TOF), transposition of the great arteries (TGA) and double outlet right ventricle (DORV) had the highest proportions, accounting for 38.00%, 18.29% and 17.58%, respectively. Among all types of conus arteriosus malformations, atresia pulmonary valve syndrome associated with TOF, persistent truncus arteriosus and DORV exhibited higher proportions of fetal cardiac axis abnormalities, at 75.00%, 36.84% and 27.03%, respectively, while TGA and interrupted aortic arch associated with B-type interruption had lower proportions of fetal cardiac axis abnormalities, at 2.60% and 4.55%, respectively. Genetic testing was conducted on 73 cases (17.34%) of fetuses with conus arteriosus malformation in this study. Among them, fetal cardiac axis abnormalities were considered positive for genetic results due to factors such as aneuploidy, copy number abnormalities, and single-gene pathogenicity. A total of 31 cases tested positive for genetic anomalies, with a positive rate of approximately 42.47%.

Conclusion

In the middle pregnancy, the fetal cardiac axis in cases of conus arteriosus malformation was significantly higher than in normal fetuses. Moreover, there were variations in fetal cardiac axis among different types of conus arteriosus malformations, and these differences were notably associated with genetic diagnostic results.