Abstract
Purpose :
As treatment options for Stargardt disease evolve, early identification of patients will become increasingly critical. Therefore, we aimed to describe functional and structural characteristics of the retina in very young patients who have a secured diagnosis of Stargardt disease (biallelic mutations in ABCA4) and were first seen in clinic before the age of 7 years, to identify features of progressive disease.
Methods :
We saw 9 patients in clinic at age 1.2-6.8 (median 5.7) years at first visit; in total these subjects made 99 visits, 32 of which occurred before age 7 years. The length of follow up for these patients was 1-14 (median 2.1) years after their initial visit. We first saw four patients because of an older sibling with ABCA4 disease, and the remaining five patients due to concern for possible retinal degeneration. We included measures of visual acuity using age appropriate tests, full-field electroretinographic (ERG) stimulus response functions, dark-adapted visual threshold (DAT), and OCT images of the maculas. For analysis, acuities were expressed as log MAR.
Results :
We grouped patients by the nature of their mutations, (1) those with biallelic null mutations (n=2), (2) those with biallelic severe mutations including severe missense mutations, or a null mutation paired with a severe missense mutation (n=2), (3) those with one severe mutation and one mild mutation including mild splice site mutations (n=3), and (4) those with biallelic mild mutations (n=2). Visual acuity was abnormal except in the youngest of patients. In a three and four year old, we found normal acuities, despite early OCT changes at the photoreceptor – pigment epithelial interface. Another had normal acuity between ages 1.2 and 2.4 years, and by OCT maintained normal macular structure. As for the full-field ERGs, the amplitude of the saturated rod response, RROD (calculated a-waves stimulus/response data), was below the 95% limit for normal. DAT elevation was significant in fewer than half, changed little with time, and only one patient progressed from normal to abnormal.
Conclusions :
We were able to identify features of this progressive disease at an early age. Data in young patients like these may aid in determining an optimal window for treatment.
This is a 2020 ARVO Annual Meeting abstract.