Factors Influencing the Delayed Diagnosis of Stargardt Disease and Impact on Therapeutic Opportunities.

Purpose: To characterize the delay between symptom onset and diagnosis in patients with early, intermediate, and late-onset Stargardt Disease (STGD) and identify possible factors contributing to this delay.

Methods: Chart review was conducted for patients with confirmed STGD molecular diagnosis seen by an inherited retinal disease (IRD) specialist at a tertiary academic institution.

Results: Eighty-seven patients were included. Average time from symptom onset to first IRD specialist visit was 10.95 years (SD=12.74). Average time between seeing a sub-specialist and IRD specialist was 8.09 years (SD=12.2), with the intermediate-onset group having a significantly longer delay (mean 13.1 years) compared to early-onset (mean 5.01 years, p=0.025) and late-onset group (mean 3.1 years, p=0.02). Visual acuity significantly decreased between seeing a sub-specialist and IRD specialist (p=0.047). Late-onset STGD patients were more likely to have intact subfoveal ellipsoid zone compared to early and intermediate-onset patients.

Conclusions: STGD patients face long delays from symptom onset to molecular diagnosis, with progressive vision loss and missed opportunities for clinical trial enrollment. Contributing factors include age of onset, types of initial symptoms, and transitions in care from sub-specialist to IRD specialist. Multimodal screening, more streamlined referral pathways, expedited genetic testing, and greater awareness of highly variable STGD phenotypes may mitigate these delays.