Rapid targeted analysis of the genome: Rapid genomic sequencing in critically ill infants

We developed a genome sequencing-based test (Rapid Targeted Analysis of the Genome for Infants [rTAG-I]) to minimize turnaround time while maximizing diagnostic yield and access to rapid sequencing for critically ill infants. We sought to create a system of predicting which infants would have a molecular finding.

We performed a prospective observational study of infants referred for genetics consult who received rTAG-I testing, which analyzes 3183 curated genes with phenotype-agnostic prioritization of pathogenic and likely pathogenic variants. Infants were stratified by perceived likelihood of a diagnostic result and divided into "Likely," "Uncertain," and "Not Likely." We also assessed whether reportable findings correlated with patient phenotypes.

We identified reportable findings in 133/400 (33%) infants. Access to rapid testing increased from 1% to 20% of all infants hospitalized in the neonatal/infant intensive care unit and cardiac intensive care unit, with a median turnaround time of 4.9 days. rTAG-I performed as well as exome/genome sequencing. Clinically associated results were identified in 59% of the "Likely" group and 9% of the "Not Likely" group.

rTAG-I produced a high rate of reportable findings with a rapid turnaround time. Our ability to predict infants who would benefit most was imperfect, reinforcing that broad access to genome-based testing is still required.