Study Examines Differences in ABCA4-Associated Retinopathies

Certain phenotypes across the spectrum of ABCA4-associated retinopathies (ABCA4R) have preferential photoreceptor degeneration, while others have substantial alterations in the retinal pigment epithelium (RPE) and choriocapillaris, according to results published in Ophthalmology Retina. Anna Paola Salvetti, MD, and colleagues examined the clinical and genotypic differences in the spectrum of ABCA4R among 66 patients (132 eyes) with biallelic ABCA4 variants. Age at disease onset was younger for cone-rod dystrophy (CRD; 12±8 years) and older for late-onset Stargardt disease (LO-SD; 59±9 years; all P<0.01). Cone dystrophy-bull’s eye maculopathy (CD-BEM) and SD commonly involved central vision loss at presentation, while patients with LO-SD mainly experienced issues adapting to the dark. Patients with LO-SD experienced larger areas of decreased autofluorescence (DDAF), a marker of RPE atrophy, and choriocapillaris flow deficits (both P<0.01). Repeatability of DDAF measurements was low for certain phenotypes, including CD-BEM and CRD, and atrophic areas of less than 7.5 mm2. The study team found a significant association between resorbed flecks with CRD and LO-SD (P<0.01). They recommend that clinical trials use these imaging features to improve interpretation of results.