P821: Long-read sequencing resolves CYP21A2 alleles in congenital adrenal hyperplasia*

We sought to evaluate clinical utility of long-read sequencing (LRS) de novo assemblies and optical genome mapping (OGM) in a research clinical setting for rare disease diagnosis. We focused on regions of the genome of critical importance for disambiguation of Differences of Sex Development (DSD) conditions refractory to diagnosis with short-read sequencing because of complexity of the genomic architecture. DSD, designated an underserved population by the NIH, are among the most difficult conditions to diagnose clinically, with a large molecular diagnostic gap.