Abstract
Purpose :
Distinguishing between ABCA4 and PRPH2-related diseases is clinically challenging due to their phenotypic similarities and is further complicated by highly variable expressivity of ABCA4-related disease. Therefore, clinicians typically rely on genetic testing in order to provide proper counseling and guidance on possible clinical trials and potential gene therapy treatments. The current study aimed to quantify specific examination and imaging features in order to determine differences present in these two disease states.
Methods :
A retrospective case series of patients managed at an urban retina-based practice between 2016 and 2022. Patients with ABCA4-confirmed Stargardt disease and/or PRPH2-confirmed pseudo-Stargardt pattern dystrophy (PSPD) were included. Color fundus photographs, fundus autofluorescence, and optical coherence tomography were analyzed by 3 masked graders (KCF, TCB, CW) independently. Features noted on clinical examination and during retrospective review of available imaging included optic nerve pallor, peripapillary sparing, flecks, dark green flecks, chorioretinal atrophy, and presence and location of intraretinal and subretinal fluid. This study was conducted in accordance with the Declaration of Helsinki under IRB-approved guidance. Statistical analysis was done with 2-tailed Student's t-tests.
Results :
In total, 62 eyes of 31 unique patients were included. 84% (52/62) of eyes were genetically confirmed ABCA4-related Stargardt disease and 16% (10/62) of eyes for PRPH2-related PSPD. ABCA4-related disease was significantly more associated with the following findings as compared to PRPH2-related PSPD: peripapillary sparing (83% vs. 38%, respectively, p = 0.004), macular flecks (71% vs. 25%, respectively, p = 0.011), and chorioretinal atrophy with sharp borders (24% vs 6%, respectively, p = 0.023). Notable features that were not statistically significantly different included central dark green pigmented flecks, bulls-eye or butterfly pattern, and presence of peripheral flecks (all p > 0.05).
Conclusions :
The current study reaffirmed that ABCA4-confirmed Stargardt disease and PRPH2-related PSPD share many clinical features and identified several examination and imaging findings such as peripapillary sparing, macular flecks, and/or chorioretinal atrophy with sharply demarcated borders that may be valuable in assisting clinical differentiation between the two diseases.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.