Understanding the etiology of Stargardt's disease.

Stargardt's disease is a form of juvenille macular degeneration. Patients with Stargardt's disease typically present in the first or second decade of life, complaining of decreased visual acuity. Recent research allows for a three-step explanation of the pathophysiology of Stargardt's disease: 1) Defective Rim Protein, a protein encoded by the ABCA4 gene, causes an accumulation of protonated N-retinylidene-PE in the rod outer segments; 2) A2-E, a byproduct of N-retinylidene-PE, then accumulates in the RPE cells and is toxic to them; 3) Photoreceptors eventually die secondary to loss of the RPE support function. With our new knowledge of the etiology of Stargardt's disease, we can devise future studies directed at treating affected patients.