High‐Resolution Genomic Characterization of <scp>WAGR</scp> Spectrum Disorder: Insights From a Novel Cohort and Literature Synthesis, and Validation of Patient‐Reported Data

WAGR spectrum disorder (WAGRSD) is an ultra-rare congenital disorder caused by heterozygous deletion of chromosome 11p13. While classically associated with Wilms tumor, Aniridia, Genitourinary anomalies, and a Range of developmental delays, accurate delineation of the deletion is critical for prognosis because the phenotypic spectrum extends well beyond this tetrad. To improve diagnostic resolution, we developed and validated a high-density custom CGH-SNP array for precise breakpoint mapping of 11p13. We present a molecularly confirmed cohort of 23 new patients and integrate these with 91 published cases, forming the largest combined cohort to date (N = 114) with detailed genotype-phenotype information. Key findings include: (1) the custom array provided superior genomic resolution compared to standard clinical arrays; (2) seven patients (6.1%) were found to have a dual diagnosis of WAGRSD and Potocki-Shaffer syndrome (PSS)-a contiguous-gene syndrome characterized by multiple osteochondromas that requires distinct surveillance; (3) in 42 patients with fully defined deletions (n = 42, 38% of the cohort), no statistically significant association was observed between deletion of LMO2 (or other candidate genes) and Wilms tumor risk; and (4) phenotypic frequencies in this medically validated cohort closely aligned with prior caregiver-reported registry data, validating patient-driven registries as a reliable resource for rare disease research. Together, these findings underscore the necessity of high-resolution genomic testing to guide counseling, refine anticipatory management-including screening for PSS-related complications-and expand the phenotypic understanding of 11p13 deletion disorders.