Defective visual phototransduction due to ABCA4 loss of function

ATP-binding cassette protein A4 (ABCA4, ABCR), expressed exclusively in retinal photoreceptors, is thought to be involved in the clearance of toxic by-products of the retinoid cycle. Defects in ABCA4 cause a diverse range of human diseases. One such disease is Stargardt's disease type 1 (STGD1, MIM:248200), an autosomal recessive form of juvenile macular degeneration leading to progressive irreversible loss of central vision and delayed dark adaptation. STGD1 was first identified by Stargardt in 1909 (Stargardt, Arch. Klin. Exp. Ophthal. 71: 534-549, 1909), has an approximate prevalence of 1 in 10,000 (see reviews Paskowitz et al. 2006, Walia & Fishman 2009) and is usually diagnosed within the first two decades of life.

Summary from Reactome (R-HSA-9918454), read 2026-09-23.