Informed Decision-Making in the Context of Prenatal Chromosomal Microarray

Disparities in the acceptance of chromosomal microarray at the time of prenatal genetic diagnosis

OBJECTIVE

Chromosomal microarray (CMA) increases the diagnostic yield of prenatal genetic diagnostic testing but is not universally performed. Our objective was to identify provider and patient characteristics associated with the acceptance of CMA at the time of prenatal genetic diagnostic testing.

METHODS

Retrospective cohort study of patients undergoing prenatal genetic diagnostic testing (chorionic villus sampling or amniocentesis) at a single institution between 2014 and 2020. Primary outcome was the acceptance of CMA based on the genetic counselor ,GC who saw the patient. Secondary analyses assessed patient characteristics associated with the acceptance of CMA.

RESULTS

2372 participants were included. Fifty-eight percent of participants accepted CMA. Acceptance of CMA varied significantly by GC, ranging from 31% to 90%. Patients with public insurance and those who identified as Black or Hispanic/Latina were less likely to have CMA performed (aOR 0.24, 95% CI 0.20-0.30, and 0.68, 95% CI 0.50-0.92). Even among those with a structural anomaly present, public insurance was associated with significantly lower odds of CMA being performed (aOR 0.39, 95% CI 0.25-0.61).

CONCLUSIONS

Acceptance of CMA at the time of prenatal genetic diagnostic testing varied based on the GC performing the counseling. Public insurance was associated with lower frequency of accepting CMA.

Retrospective identification of prenatal fetal anomalies associated with diagnostic neonatal genomic sequencing results

OBJECTIVE

To determine which types of fetal anomalies are associated with postnatal diagnoses of genetic diseases by genomic sequencing and to assess how prenatal genomic sequencing could affect clinical management.

METHOD

This was a secondary analysis of the second Newborn Sequencing in Genomic Medicine and Public Health study that compared fetal imaging results in critically ill infants who had actionable versus negative postnatal genomic sequencing results.

RESULTS

Of 213 infants who received genomic sequencing, 80 had available prenatal ultrasounds. Twenty-one (26%) of these were found to have genetic diseases by genomic sequencing. Fourteen (67%) of the 21 with genetic diseases had suspected anomalies prenatally, compared with 33 (56%) of 59 with negative results. Among fetuses with suspected anomalies, genetic diseases were 4.5 times more common in those with multiple anomalies and 6.7 times more common in those with anomalies of the extremities compared to those with negative results. Had the genetic diseases been diagnosed prenatally, clinical management would have been altered in 13 of 14.

CONCLUSION

Critically ill infants with diagnostic genomic sequencing were more likely to have multiple anomalies and anomalies of the extremities on fetal imaging. Among almost all infants with suspected fetal anomalies and diagnostic genomic sequencing results, prenatal diagnosis would have likely altered clinical management.

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.

Maternity health care professionals' views and experiences of fetal genomic uncertainty: A review

The field of prenatal screening and diagnosis for fetal anomalies has been marked by a rapid succession of technological advances, including most notably, chromosomal microarray analysis, and next generation sequencing. Despite the diagnostic advantages of these technologies, their incorporation into prenatal testing has created additional challenges of revealing genomic variants of unknown or uncertain significance, and secondary findings. While detailed posttest counseling about uncertain variants is best performed by medical geneticists, many of the screening and diagnostic tests that lead to this information are actually ordered by general maternity health care professionals (HCPs), such as obstetricians, midwives, and family physicians. Maternity HCPs support pregnant women through to the conclusion of their pregnancy and the postpartum period, and thus are close observers of the psychosocial impart of fetal genomic uncertainty on women and their families. While there have been many studies exploring the handling of genomic uncertainty by genetics HCPs, there has been relatively less attention paid to maternity HCPs without speciality training in genetics. This review explores the current literature surrounding nongenetic maternity HCPs' views and experiences of genomic uncertainty and returning uncertain results in the prenatal setting.