CRX rs104894488: Understanding This Rare Genetic Variant
The rs104894488 variant is a rare genetic change located within the CRX gene, which provides instructions for proteins essential to eye development. This variant has been associated with inherited retinal conditions, including autosomal dominant cone-rod dystrophy and Leber congenital amaurosis.
What each genotype means
Typical retinal development
This genotype represents the common, non-variant sequence for this location in the CRX gene. It is not associated with the rare, inherited retinal dystrophies linked to pathogenic mutations in this gene.
This is the most common genotype found in the general population.
Potential retinal dystrophy risk
This genotype indicates the presence of a rare variant in the CRX gene, which is associated with autosomal dominant cone-rod dystrophy or Leber congenital amaurosis. Because this condition can show significant phenotypic variability even within families, clinical evaluation by an ophthalmologist or genetic counselor is recommended to understand its specific implications for your vision health.
This genotype is ultra-rare, with an allele frequency reported at less than 0.00001 in global population databases.
Potential retinal dystrophy risk
This genotype indicates the presence of two copies of a rare variant in the CRX gene, which is associated with autosomal dominant cone-rod dystrophy or Leber congenital amaurosis. Given the association of CRX variants with progressive retinal degeneration, professional clinical assessment is essential to determine if this finding correlates with any symptoms or clinical signs.
This genotype is extremely rare and is not typically observed in general population cohorts.
What is the rs104894488 Variant?
The rs104894488 variant is a specific change in the DNA sequence of the CRX gene. In genetics, an rsID (reference SNP cluster ID) acts as a unique identifier for a particular location in the human genome where a variation may occur. This specific variant is found on chromosome 19. Because the human genome is vast, researchers use these identifiers to track where specific changes occur and to study whether those changes correlate with physical traits or health conditions. For rs104894488, the variation is considered ultra-rare, meaning it is found in a very small fraction of the general population. Geneticists study such variants to understand how even minor alterations in our DNA code can influence the complex biological processes that allow our bodies to function, particularly in specialized tissues like the retina.
The Role of the CRX Gene
The CRX gene, which stands for cone-rod homeobox, plays a critical role in the development and maintenance of the eye. It encodes a transcription factor, a type of protein that acts like a master switch, binding to DNA to turn other genes on or off. Specifically, the CRX protein is vital for the differentiation of photoreceptor cells in the retina. These cells, known as rods and cones, are responsible for detecting light and color. Rods allow us to see in low-light conditions, while cones are essential for bright light and color vision. By regulating the expression of genes necessary for these cells to mature and survive, the CRX protein ensures that the retina can effectively process visual information. When the CRX gene is altered, the resulting protein may not function correctly, which can disrupt the health and survival of these light-sensitive cells.
Research and Clinical Associations
Scientific research has linked various mutations in the CRX gene to a spectrum of inherited retinal diseases. These conditions include cone-rod dystrophy, where patients experience progressive loss of visual acuity, sensitivity to light, and impaired color vision, as well as Leber congenital amaurosis, a severe form of retinal degeneration that often presents in childhood. The evidence for these associations is grounded in clinical studies where researchers have identified specific CRX variants in families affected by these conditions. However, it is important to note that the evidence strength for any single variant can vary. While the CRX gene is well-established as a cause of these retinal disorders, the clinical impact of a specific variant like rs104894488 requires careful interpretation by medical professionals. Because these conditions are rare, ongoing research is essential to fully understand the range of symptoms and the underlying mechanisms of how these genetic changes lead to vision loss.
Population Frequency and Interpretation
According to large-scale genomic databases like gnomAD, the rs104894488 variant is classified as ultra-rare, with an allele frequency of less than 0.00001. This means the variant is extremely uncommon across the diverse populations studied. Because it is so rare, there is limited data on how it manifests across different ancestral backgrounds. For individuals who may encounter this information, it is crucial to understand that the presence of a genetic variant does not automatically equate to a medical diagnosis. Genetic testing results should always be interpreted in the context of a person's clinical history, family history, and physical examination by a qualified healthcare provider, such as a genetic counselor or an ophthalmologist specializing in retinal diseases. This information is for educational purposes and should not be used to make personal health decisions or to diagnose any condition.
How common is this variant?
The rs104894488 variant is ultra-rare, with a reported allele frequency of less than 0.00001 in gnomAD, making it extremely uncommon across all studied populations.
Frequently asked questions
What is the CRX gene?
The CRX gene provides instructions for making a protein that is essential for the development and function of photoreceptor cells in the retina. These cells are responsible for detecting light and color.
Is rs104894488 associated with blindness?
Variants in the CRX gene are associated with inherited retinal diseases that can lead to progressive vision loss. However, the clinical outcome depends on the specific mutation and other individual factors.
Should I get tested for this variant?
Genetic testing is typically recommended only if you have symptoms of a retinal condition or a family history of inherited eye disease. You should discuss the necessity of testing with a genetic counselor or an eye specialist.
What does 'autosomal dominant' mean?
Autosomal dominant means that a person only needs to inherit one copy of a mutated gene from one parent to potentially develop the associated condition. It does not skip generations in the same way as recessive traits.
Sources & further reading
Educational information only, last refreshed 9/22/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Pathogenic homeodomain mutation associated with autosomal dominant cone-rod dystrophy and Leber congenital amaurosis.
A dominant missense variant in the CRX homeobox transcription factor causing Leber congenital amaurosis and cone-rod dystrophy.
A missense variant in the CRX homeodomain disrupting retinal photoreceptor cell differentiation and survival.
Pathogenic missense variant in the CRX homeodomain associated with autosomal dominant cone-rod dystrophy and severe visual impairment.
Encodes the Glu80Ala missense change in the cone-rod homeobox factor, causing autosomal dominant cone-rod dystrophy and severe visual acuity decline.
This pathogenic variant in the CRX gene is linked to Retinitis pigmentosa, affecting retinal photoreceptor development.