Exome sequencing and targeted gene panels: a simulated comparison of diagnostic yield using data from 158 patients with rare diseases

Prenatal exome and genome sequencing for fetal structural abnormalities

As prenatal exome sequencing becomes integrated into clinical care, it is critical that providers caring for women with fetal anomalies recognize not only the benefits, but also the challenges and considerations related to this technology. This overview of prenatal sequencing includes information about indications for sequencing, methods, diagnostic yield, clinical utility, variant interpretation, ethical considerations and dilemmas, practical considerations (ie, turnaround time and cost), pre- and posttest counseling points, and psychological impact of testing on families.

Clinical and psychological implications of secondary and incidental findings in cancer susceptibility genes after exome sequencing in patients with rare disorders

Background/Objectives

Exome sequencing may identify pathogenic variants unrelated with the purpose of the analysis. We investigated the frequency of secondary and incidental findings (SF/IF) in cancer susceptibility genes (CSG), their clinical actionability and the psychological impact in individuals with an SF/IF (cases) compared with individuals tested due to their cancer history (controls).

Methods

This study analysed 533 exomes ordered for non-cancer conditions. Medical records were reviewed for clinical actionability of SF/IF. Psychological impact was analysed using the Multidimensional Impact of Cancer Risk Assessment (MICRA) scale and compared between cases and controls with a propensity score weighting method.

Results

The frequency of SF/IF in CSG was 2.1% (95% CI 1.1% to 3.8%): threeBRCA2, threePMS2, twoSDHB, and one each inBRCA1,MLH1andRAD51C. Among the relatives, 18 were carriers. Twenty enrolled for surveillance, and a neoplasm was diagnosed in 20%: three paragangliomas and one breast cancer. Cases presented higher MICRA mean scores than controls (21.3 vs 16.2 in MICRA total score, 6.3 vs 4.2 in the distress subscale, and 8.3 vs 6.6 in the uncertainty subscale; all p<0.001).

Conclusion

SF/IF in CSG were identified in 2.1% of patients. Despite a numerically higher psychological impact, the identification of SF/IF allowed early detection and cancer prevention in families without cancer history.