ABCA4 and Stargardt disease: Stargardt disease (STGD1; Online Mendelian Inheritance in Man identifier, 248200) is an autosomal recessive retinal dystrophy resulting from dysfunction in the photoreceptor-specific ATP-binding cassette transporter ABCA4. To date, more than 1000 mutations in ABCA4 have been reported, associated with phenotypes that include macular, cone, or cone–rod dystrophies.1