ABCA4
ATP binding cassette subfamily A member 4
Normal Function
Health Conditions Related to Genetic Changes
Cone-rod dystrophy
Many variants (also called mutations) in the ABCA4 gene have been found to cause a vision disorder called cone-rod dystrophy. The problems associated with this condition include a loss of visual sharpness (acuity), an increased sensitivity to light (photophobia), and impaired color vision. These vision problems worsen over time. It is estimated that ABCA4 gene variants account for 30 to 60 percent of cases of cone-rod dystrophy that are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder.
Most of the ABCA4 gene variants that cause cone-rod dystrophy change single protein building blocks (amino acids) in the ABCA4 protein. The altered protein cannot remove N-retinylidene-PE from photoreceptors. As a result, N-retinylidene-PE combines with another substance to produce a molecule called N-retinylidene-N-retinylethanolamine (A2E), which builds up in these cells. The buildup of A2E is toxic to photoreceptors and leads to their deterioration, causing progressive vision loss in people with cone-rod dystrophy. Cone-rod dystrophy caused by ABCA4 gene variants tends to be associated with more severe vision problems than cone-rod dystrophy caused by other genetic variants.
More About This Health ConditionRelated Conditions
Cone-rod dystrophyStargardt macular degenerationAge-related macular degenerationRetinitis pigmentosa
Health Conditions Related to Genetic Changes
Many variants (also called mutations) in the ABCA4 gene have been found to cause a vision disorder called cone-rod dystrophy. The problems associated with this condition include a loss of visual sharpness (acuity), an increased sensitivity to light (photophobia), and impaired color vision. These vision problems worsen over time. It is estimated that ABCA4 gene variants account for 30 to 60 percent of cases of cone-rod dystrophy that are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder.
Most of the ABCA4 gene variants that cause cone-rod dystrophy change single protein building blocks (amino acids) in the ABCA4 protein. The altered protein cannot remove N-retinylidene-PE from photoreceptors. As a result, N-retinylidene-PE combines with another substance to produce a molecule called N-retinylidene-N-retinylethanolamine (A2E), which builds up in these cells. The buildup of A2E is toxic to photoreceptors and leads to their deterioration, causing progressive vision loss in people with cone-rod dystrophy. Cone-rod dystrophy caused by ABCA4 gene variants tends to be associated with more severe vision problems than cone-rod dystrophy caused by other genetic variants.
More than 1,000 variants in the ABCA4 gene have been found to cause Stargardt macular degeneration. Variants in this gene are the most common cause of this eye disease. Stargardt macular degeneration is characterized by vision loss that worsens over time.
Most of these variants change amino acids in the ABCA4 protein. A malfunctioning ABCA4 protein cannot remove N-retinylidene-PE from photoreceptors. As a result, N-retinylidene-PE combines with another substance to produce a fatty yellow pigment called lipofuscin, which builds up in retinal cells. The buildup of lipofuscin is toxic to the cells of the retina and causes progressive vision loss in people with Stargardt macular degeneration.
MedlinePlus Genetics provides information about Age-related macular degeneration
MedlinePlus Genetics provides information about Retinitis pigmentosa