Clinical spectrum, genetics and management insights of PAX2-related disorder in nine children.

Renal coloboma syndrome (RCS) is a rare autosomal dominant genetic disorder associated with the paired box gene 2 (PAX2). Over the past three decades, PAX2 variants have manifested with vast phenotype and genotype heterogeneity, with limited experience gained regarding its clinical progression and management strategies. We included nine Chinese children diagnosed with PAX2-related disorder at Beijing Children's Hospital. The medical records were retrospectively reviewed, and the demographic data, clinical manifestations, genetic testing results, imaging examination findings, laboratory tests, and renal biopsy results were recorded and analyzed. Eight distinct PAX2 pathogenic variants, including four novel variants, were identified in nine children. All patients exhibited developmental abnormalities of the urinary system, while two presented with ocular abnormalities with retinal myelinated nerve fibers identified as a novel manifestation of PAX2-related disorder. Cranial imaging examinations were performed on three patients, revealing vascular anatomical abnormalities. Five patients received empirical treatment with angiotensin-converting enzyme inhibitors (ACEIs), resulting in varied therapeutic outcomes. PAX2 variants exhibit significant clinical diversity, and our findings further expand the genotype-phenotype spectrum of PAX2-related disorder. The variable efficacy of ACEIs highlights the importance of personalized evaluation and treatment strategies and extended follow-up periods in the future.