Purpose
To document the temporal changes in SD OCT and AF findings in 3 young siblings initially seen at ages 4, 5 and 8, with genetically confirmed Stargardt Disease (STGD).
Methods
Serial evaluation of 3 siblings with fundus photography, OCT, full field ERGs, ultra-widefield auto fluorescence (UWF-AF) and genetic testing.
Results
At initial presentation, only the 8 yo brother had visual symptoms with VA reduced to 20/200 in each eye. Although ophthalmoscopy appeared normal, SD OCT showed profound macula thinning and loss of much of the outer retina. FAF revealed hyper AF within the arcades as well as small hyper and hypo AF pisciform lesions that were quite symmetric in both eyes. ERGs were normal and genetic testing revealed an ABCA4 (Pro1380Leu) mutation.<br /> Both the 4 and 5 yo sisters had no visual symptoms initially, VA of 20/25 in each eye, normal fundi, but each demonstrated a thickened, hyper-reflective ELM (external limiting membrane) and attenuated EZ (elipsoid zone) on SD OCT. The 8 yo brother had no detectable ELM or EZ in the central 4 mm of the scans.<br /> Over the next 2 yrs the brother's VA worsened to 20/400 OU as did both the OCT and UWF AF abnormalities. The older sister did not appear to change significantly during the first year of follow-up but about a year later (at age 7) showed marked changes on SD OCT. The ELM, which 1 and 2 years earlier was grossly thickened throughout the entire 6 mm scan was almost completely absent in the central macula except at the fovea as a concave protuberance. Less dramatic was the loss of the EZ in the central macula in both eyes. At presentation, only the older sister had an obvious bull's eye on AF OU. All 3 siblings had progressive AF changes.
Conclusions
In this pedigree, the thickened ELM was a transient biomarker for STGD that was imaged in a 4 and 5 year old. The thickened ELM occurred both before symptoms and VA loss. Since treatment for STGD may well be a reality in the near future, knowledge of this biomarker and its natural course during the first decade may be helpful in deciding who to treat and to determine drug efficacy.