In<unk> 1, the genetic defect causes malfunction of the ATP-binding cassette transporter (ABCA4) protein of the visual phototransduction cycle. Defective ABCA4 leads to improper shuttling of vitamin A throughout the retina, and accelerated formation of toxic vitamin A dimers (also known as bisretinoids), and associated degradation byproducts. Vitamin A dimers and other byproducts are widely accepted as the cause of<unk> 1. As such, slowing the formation of vitamin A dimers might lead to a treatment for<unk> . When vitamin A dimers and byproducts damage the retinal cells, fluorescent granules called lipofuscin in the retinal pigmented epithelium of the retina appear, as a reflecting such damage. In<unk> 4, a butterfly pattern of dystrophy is caused by mutations in a gene that encodes a membrane bound protein that is involved in the elongation of very long chain fatty acids (ELOVL4)
Stargardt disease
Akureyri disease
Pickardt syndrome
Batten disease
Keshan disease
Lafora disease
Thiel–Behnke dystrophy
Bosch-Boonstra-Schaaf optic atrophy syndrome