Clinical utility of genome sequencing in rare diseases: lessons from a single-center study of 1,452 Korean families.

Genome sequencing (GS) was applied to 3317 individuals from 1452 Korean families with suspected rare genetic disorders to assess diagnostic yield and clinical utility. Patients were categorized into 16 clinical subgroups with curated phenotypes, and variant interpretation was refined by post-analytic phenotype matching. A molecular diagnosis was achieved in 46.2% of families, influencing clinical management in 18.5% of diagnosed cases. Family-based GS had a higher yield than singleton testing (48.5% vs. 41.5%). Neuromuscular and neurodevelopmental disorders showed the highest yields. GS-specific variant types, including deep intronic, noncoding, complex structural variants, and tandem repeat expansions, accounted for 14.6% of diagnoses. Secondary findings were identified in 4.3% of individuals. Novel disease-associated genes such as RYBP, DNAJA3, CAMK2D, and small nuclear RNA genes were also reported. These results highlight the diagnostic power of GS and support its use as a first-tier test, especially in underrepresented populations.