ABCA4 is a gene that provides instructions for making a protein involved in the transport of certain molecules in the retina, the light-sensitive tissue at the back of the eye. This protein plays a crucial role in the visual cycle, helping to clear out waste products that can accumulate during the process of vision. Mutations in the ABCA4 gene can lead to various eye disorders, including Stargardt disease and retinitis pigmentosa. These conditions can cause progressive vision loss and are often inherited in an autosomal recessive manner, meaning that both copies of the gene must be mutated for the disease to manifest.