HEXA rs386833394: Understanding This Splice-Junction Variant
The rs386833394 variant is a specific genetic change located in the HEXA gene, which provides instructions for making an enzyme essential for nerve cell function. This variant is classified as a pathogenic splice-junction mutation and is associated with carrier status for Tay-Sachs disease.
What each genotype means
Typical risk profile
You do not carry the pathogenic c.1073+1G>A splice variant in the HEXA gene associated with Tay-Sachs disease. Having this typical genotype means you are not an identified carrier for this specific mutation, though standard genetic carrier screening evaluates additional variants across the HEXA gene. Your likelihood of passing this particular altered allele to offspring is not increased.
Carried by greater than 99.9% of individuals across global populations in gnomAD.
Tay-Sachs disease carrier
You carry one copy of the c.1073+1G>A splice-site variant in the HEXA gene, identifying you as an asymptomatic carrier of Tay-Sachs disease. Carriers typically have sufficient beta-hexosaminidase A enzymatic activity to remain completely healthy without developing symptoms. If having children, prospective parents often consider carrier status information and genetic counseling to understand reproductive risks.
Very rare in the general population (~1 in 50,000 individuals in gnomAD), but enriched among individuals of Ashkenazi Jewish ancestry.
Tay-Sachs disease risk
You carry two copies of the c.1073+1G>A pathogenic variant, which disrupts the canonical donor splice site in the HEXA gene. In genetic research, homozygous or compound heterozygous loss-of-function variants in HEXA cause Tay-Sachs disease due to severe hexosaminidase A deficiency. Individuals with this genotype should review their findings with a medical geneticist or clinical genetics professional.
Extremely rare across all populations, estimated at far less than 1 in 1,000,000 births outside specific founder groups.
What is the rs386833394 Variant?
The variant rs386833394, also known in clinical literature as c.1073+1G>A or IVS9+1G>A, is a single nucleotide change located within the HEXA gene. This gene is situated on chromosome 15. Specifically, this variant occurs at a canonical splice-donor site in intron 9. Splice sites are critical sequences in DNA that act as signals for the cellular machinery to correctly assemble the final messenger RNA (mRNA) transcript by removing non-coding regions called introns. When a mutation occurs at a splice-junction, it can disrupt the normal splicing process, often leading to the production of an unstable or non-functional protein. Because this variant directly interferes with the accurate processing of the HEXA gene's instructions, it is categorized as a pathogenic variant, meaning it has the potential to cause disease if inherited in a specific manner.
The Role of the HEXA Gene
The HEXA gene provides the blueprint for the alpha subunit of an enzyme called beta-hexosaminidase A. This enzyme is primarily active in lysosomes, which are the recycling centers of the cell. Its main job is to break down a fatty substance known as GM2 ganglioside. In a healthy individual, this process prevents the toxic buildup of fatty materials within nerve cells (neurons) in the brain and spinal cord. When the HEXA gene contains pathogenic variants that significantly reduce or eliminate the activity of beta-hexosaminidase A, GM2 ganglioside accumulates to dangerous levels. This accumulation leads to the progressive destruction of neurons, which is the underlying mechanism of GM2 gangliosidoses, a group of neurodegenerative disorders that includes Tay-Sachs disease. The severity of the condition often depends on how much residual enzyme activity remains.
Research and Clinical Significance
Research has established that rs386833394 is a pathogenic variant associated with Tay-Sachs disease. Tay-Sachs is an autosomal recessive condition, meaning an individual must typically inherit two copies of a pathogenic variant—one from each parent—to manifest the disease. Individuals who carry only one copy of this variant are generally considered carriers and typically do not show symptoms of the disease. However, if two carriers conceive a child, there is a statistical risk of passing on the condition. While this variant is well-documented in clinical databases like ClinVar, it is important to note that the evidence strength for specific clinical outcomes can vary based on the broader genetic context of the individual. Genetic testing for such variants is often used in carrier screening programs to help families understand their reproductive risks and make informed decisions with the guidance of a genetic counselor.
Population Frequency
The frequency of the rs386833394 variant varies across different ancestral groups. According to data from the Genome Aggregation Database (gnomAD), the allele frequency is approximately 0.00002. While it is found at low levels globally, it has been noted as being enriched in individuals of Ashkenazi Jewish ancestry. Historically, Tay-Sachs disease has been more frequently observed in this population, leading to widespread carrier screening initiatives. It is also important to recognize that this variant has been reported in non-Ashkenazi Jewish populations of European descent, indicating that it is not exclusive to any single ethnic group. Because carrier frequencies can differ significantly between populations, understanding one's own ancestral background and family history is a key component of interpreting genetic screening results.
What You Can Do With This Information
If you have received information regarding your status for the rs386833394 variant, it is essential to approach the data with professional guidance. This information is intended for educational purposes and does not constitute a medical diagnosis. If you are concerned about your carrier status or reproductive risks, the most appropriate step is to consult with a board-certified genetic counselor or a medical geneticist. These professionals can help you interpret your results in the context of your personal and family health history. They can also explain the implications of being a carrier, discuss the limitations of current genetic testing, and provide information on available screening options for partners. Never make reproductive or medical decisions based solely on a genetic report without first discussing the findings with a qualified healthcare provider who can offer personalized clinical context.
How common is this variant?
The rs386833394 variant is rare, with a gnomAD allele frequency of approximately 0.00002, though it shows enrichment in individuals of Ashkenazi Jewish ancestry.
Frequently asked questions
What is Tay-Sachs disease?
Tay-Sachs disease is a rare, inherited neurodegenerative disorder caused by the buildup of a fatty substance called GM2 ganglioside in nerve cells. This accumulation occurs because the body lacks a necessary enzyme, beta-hexosaminidase A, due to mutations in the HEXA gene.
Does having this variant mean I have Tay-Sachs?
Not necessarily. Being a carrier (having one copy of the variant) typically does not cause symptoms. Tay-Sachs is an autosomal recessive condition, meaning it usually requires inheriting two copies of a pathogenic variant to manifest the disease.
Should I be tested for this variant?
Carrier screening is a personal decision often discussed with a healthcare provider or genetic counselor. It is particularly relevant for individuals with a family history of Tay-Sachs or those from populations with a higher known carrier frequency.
Can this variant be treated?
There is currently no cure for Tay-Sachs disease, and management focuses on supportive care to address symptoms. If you have concerns about your genetic status, please consult a medical professional to discuss your specific situation.
Sources & further reading
Educational information only, last refreshed 10/12/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Canonical splice junction variant (c.1073+1G>A) causing Tay-Sachs disease.
Pathogenic splice donor variant (c.1421+1G>C) in HEXA underlying carrier status for autosomal recessive infantile Tay-Sachs disease.
This HEXA variant is associated with Tay-Sachs disease, particularly late-onset forms.
Pathogenic splice junction mutation (c.1421+1G>C) in HEXA leading to Tay-Sachs disease.
Pathogenic HEXA splice donor site mutation (c.1073+1G>A) causing Tay-Sachs disease, common in carrier screening panels for Ashkenazi Jewish and French Canadian ancestry.
A canonical splice-donor variant (c.1421+1G>C) in HEXA resulting in absent functional beta-hexosaminidase A, representing a classical Tay-Sachs carrier allele.