Thesis defense Esmee Runhart (Donders series 522)

4 November 2021

Promotors: C.B. Hoyng, F.P.M. Cremers

Stargardt disease - ABCA4 and beyond

Stargardt disease is an as yet untreatable, hereditary macular degeneration that leads to blindness. The aim of this study was to obtain a more complete picture of the genetic causes and disease course, to improve patient counseling and the chance of finding a treatment. The research showed that many patients (almost 50%) have a mild DNA change (in the ABCA4 gene) and that they often develop first symptoms at a later age. However, the age of onset among these patients varied widely, also among siblings harboring the same ABCA4 changes. Moreover, the mild ABCA4 changes did not lead to disease in everyone and women seemed to be more often affected than men. These findings complicate counseling to patients and relatives, and raise new questions about the disease causes, which until now have only been sought in the ABCA4 gene. The dissertation offers guidelines for genetic counseling to patients and their families. In addition, the knowledge of the new mild ABCA4 changes offers an opportunity for ophthalmologists to distinguish late-onset Stargardt disease from age-related macular degeneration, which is much more common, may resemble Stargardt disease and requires a different management. Further research into possible additional disease causes outside the ABCA4 gene is needed to improve our knowledge of the disease and the chances of finding a treatment.