A nationwide Belgian randomized trial reported that genome sequencing substantially improved diagnostic yield for developmental disorders compared with standard testing workflows. In the trial of 567 patients, genome sequencing diagnosed 39.8% of cases versus exome sequencing plus chromosomal microarray, which achieved lower rates. The headline is the magnitude and replicability of the improvement, strengthening the case for earlier, broader genomic testing in children with complex developmental phenotypes where diagnostic odysseys delay targeted care. For labs and payers, the findings support workflow redesign—aligning consent, turnaround-time targets, and variant interpretation capacity to accommodate a shift toward whole-genome approaches.