The external limiting membrane in early-onset Stargardt disease

Area of Science:

• Ophthalmology
• Genetics
• Cell Biology

Background:

• Stargardt disease (STGD1) is a common inherited macular degeneration.
• Early-onset STGD1 is associated with mutations in the ABCA4 gene.
• Pathologic changes in the external limiting membrane (ELM) are not well-characterized in young STGD1 patients.

Purpose of the Study:

• To investigate and describe the pathological alterations of the external limiting membrane (ELM) in young individuals diagnosed with early-onset Stargardt disease (STGD1).

Main Methods:

• Studied 26 STGD1 patients under 20 with confirmed ABCA4 mutations and 30 age-matched controls.
• Utilized spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (AF), and color fundus photography (CFP).
• Collected data over 1-4 visits per patient, including full-field electroretinograms.

Main Results:

• All STGD1 patients displayed a thickened ELM, unlike controls.
• Reflective deposits were observed in the outer nuclear layer of all patients.
• Four patients showed foveal ELM bulging; longitudinal data confirmed ELM abnormality persistence.

Conclusions:

• The observed ELM structural changes in early-onset STGD1 suggest a gliotic response.
• This gliosis may be a reaction to cellular stress occurring at the photoreceptor level.
• Findings highlight ELM abnormalities as a potential biomarker in STGD1 progression.