ABCA4 rs768278935: Understanding Carrier Status
The rs768278935 variant is located within the ABCA4 gene, which plays a critical role in retinal health. It is currently identified in genetic databases as a marker associated with carrier status for Stargardt disease, an inherited condition affecting vision.
What each genotype means
Typical ABCA4 genotype
This genotype represents the common, non-variant form of this specific location in the ABCA4 gene. It is not associated with the increased risk of Stargardt disease linked to the T allele.
This is the most common genotype observed across all global populations.
Stargardt disease carrier status
Individuals with this genotype carry one copy of the T variant, which is associated with Stargardt disease. Because this condition is typically inherited in an autosomal recessive pattern, carrying a single copy generally does not cause the disease, though you should consult with a genetic counselor or clinician to understand your specific reproductive risks.
This genotype is rare, with an overall frequency of approximately 0.007% in the gnomAD database, though it may be more common in specific ancestral groups.
Potential Stargardt disease risk
This genotype indicates the presence of two copies of the T variant. Research indicates this variant is associated with Stargardt disease, an inherited retinal disorder, and individuals with this genotype should discuss these findings with an ophthalmologist or genetic specialist for clinical evaluation.
This genotype is extremely rare in the general population.
What is the rs768278935 Variant?
The rs768278935 variant is a specific change in the DNA sequence of the ABCA4 gene. In genomics, an rsID (reference SNP identification number) acts as a unique label for a specific location in the human genome where a single nucleotide polymorphism (SNP) or other small variation may occur. This particular variant is categorized as a carrier status marker. When researchers study such variants, they look at how the presence of a specific allele—one of the two versions of the DNA sequence at that spot—correlates with biological traits or disease risks. Because this variant is rare, it is primarily studied in the context of clinical genetics to understand its potential impact on protein function and its inheritance patterns within families.
The Role of the ABCA4 Gene
The ABCA4 gene provides instructions for making a protein called the ATP-binding cassette transporter, sub-family A, member 4. This protein is primarily found in the retina, the light-sensitive tissue at the back of the eye. Its main function is to act as a 'flippase,' a type of transporter that moves vitamin A derivatives out of photoreceptor cells. By clearing these substances, the ABCA4 protein prevents the accumulation of toxic byproducts that could otherwise damage the retina. When the ABCA4 gene is altered, the resulting protein may function poorly or not at all. This loss of function is the underlying cause of several inherited retinal disorders, most notably Stargardt disease, which is characterized by the progressive degeneration of the macula, the part of the retina responsible for sharp, central vision.
Research and Evidence Strength
Current evidence linking rs768278935 to clinical outcomes is classified as moderate. Stargardt disease is inherited in an autosomal recessive pattern, meaning an individual typically needs to inherit two pathogenic variants—one from each parent—to manifest the condition. As a carrier, an individual possesses one copy of a variant and one functional copy of the gene, usually showing no symptoms of the disease themselves. Research into ABCA4 is complex due to the gene's large size and the high number of different variants that can contribute to disease. Scientists use longitudinal studies and functional assays to determine how specific variants affect mRNA splicing or protein stability. Because many ABCA4 variants are rare, establishing a definitive clinical impact for every single SNP requires ongoing data collection and large-scale genomic sequencing efforts.
Population Frequency
The rs768278935 variant is considered rare across global populations. In genetic studies, 'rare' typically indicates that the variant is found in a very small percentage of the general population. Because it is not a common polymorphism, its frequency does not vary significantly in a way that suggests a strong founder effect in most major ethnic groups. Researchers rely on databases like gnomAD to track these frequencies, which helps distinguish between common benign variations and rare, potentially pathogenic ones. If you are interested in your own genetic profile, it is important to remember that population-level statistics describe groups, not individuals. The rarity of this variant means that most people will not carry it, and even for those who do, the clinical implications depend heavily on the presence of other variants in the same gene.
Navigating Genetic Information
Understanding your carrier status for a condition like Stargardt disease can be a significant piece of health information, but it should be approached with care. A carrier status result does not mean you have the disease, nor does it guarantee that you will pass it on to your children in a way that causes symptoms, as this depends on the genetic status of your partner. You cannot use this information to diagnose yourself or predict future vision health. If you have concerns about your results or family history, the most appropriate step is to consult with a certified genetic counselor or an ophthalmologist specializing in retinal genetics. These professionals can help interpret your specific findings in the context of your overall health and provide guidance on whether further clinical testing or family screening is appropriate.
How common is this variant?
The rs768278935 variant is rare in the general population, with low allele frequencies observed across major ancestral groups in databases like gnomAD.
Frequently asked questions
What does it mean to be a carrier for Stargardt disease?
Being a carrier means you have one copy of a gene variant associated with the condition, but you typically do not show symptoms. Stargardt disease is recessive, so you would generally need to inherit a second variant from your other parent to be at risk for the disease.
Does having this variant mean I will go blind?
No. Being a carrier for a recessive condition like Stargardt disease does not mean you will develop the disease or experience vision loss. It is a status that primarily relates to reproductive planning and family health history.
Should I get my children tested if I am a carrier?
Genetic testing for children is a personal decision that should be discussed with a pediatrician or a genetic counselor. They can help you understand the likelihood of your children being carriers and whether testing provides any actionable health benefits.
How accurate are genetic tests for rare variants?
Modern sequencing technologies are highly accurate, but rare variants can sometimes be difficult to detect or interpret. Always confirm significant genetic findings with a clinical-grade test ordered by a healthcare provider.
Sources & further reading
Educational information only, last refreshed 9/28/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A well-documented pathogenic missense change in ABCA4 causing autosomal recessive Stargardt disease and cone-rod dystrophy.
This variant is associated with carrier status for Stargardt disease, an inherited retinal disorder.
Pathogenic missense variant in ABCA4 (p.Leu541Pro) causing Stargardt disease and juvenile macular dystrophy.
This variant is a pathogenic marker associated with ABCA4-related disorders, including Stargardt disease, cone-rod dystrophy, and retinitis pigmentosa.
Pathogenic missense variant (p.Gly1961Glu) in ABCA4 causing Stargardt disease and macular degeneration phenotypes.
A well-characterized hypomorphic missense variant (p.Gly1961Glu) in ABCA4 responsible for late-onset Stargardt disease with predominantly foveal-sparing macular atrophy.