Real world outcomes and implementation pathways of exome sequencing in an adult genetic department

Purpose: This study aimed to correlate the indications and diagnostic yield of exome sequencing (ES) in adult patients across various clinical settings. The secondary aim was to examine the clinical utility of ES in adult patients. Methods: Data on demographics, clinical indications, results, management changes, and cascade testing were collected for 250 consecutive patients who underwent ES through an adult genetics department between 2016 and 2021. Data were analyzed using descriptive and inferential statistics. Testing in which traditional gene panels were in standard use, such as in heritable cancers, was excluded. Results: The average age at testing was 43 years (range = 17-80 years). A molecular diagnosis was identified in 29% of patients. Older age at symptom onset did not pre-exclude a substantial diagnostic yield. Patients with syndromic intellectual disability and multiple system disorders had the highest yield. In >50% of patients with an exome diagnosis, the results changed management. Cascade testing occured in at least one family member for 30% of patients with a diagnosis. Diagnostic results had reproductive implications for 26% of patients and 31% of patients’ relatives. Conclusion: ES has a robust diagnostic yield and clear clinical utility in adult patients across a range of ages and phenotypes.