ELP1 rs121908298: Understanding the Familial Dysautonomia Variant
The rs121908298 variant, also known as c.2204+6T>C, is a well-documented genetic mutation in the ELP1 gene. It is primarily recognized as a founder mutation associated with familial dysautonomia, an autosomal recessive condition that affects the development and survival of sensory and autonomic neurons.
What each genotype means
Typical genotype
This genotype represents the typical sequence at this location in the IKBKAP gene. It is not associated with the splicing defect that causes familial dysautonomia.
This is the most common genotype in the general population.
Carrier status
You carry one copy of the c.2204+6T>C mutation, which is a known founder mutation for familial dysautonomia. As this is an autosomal recessive condition, carriers typically do not exhibit symptoms of the disease, but you may wish to consult with a genetic counselor regarding reproductive risks.
This genotype is found in approximately 1 in 30 individuals of Ashkenazi Jewish ancestry.
Increased risk genotype
This genotype indicates the presence of two copies of the c.2204+6T>C mutation, which is the primary cause of familial dysautonomia (Riley-Day syndrome). This condition is an autosomal recessive neurodegenerative disorder characterized by sensory and autonomic nerve dysfunction; please consult with a medical professional for clinical evaluation and guidance.
This genotype is rare and is primarily observed in individuals of Ashkenazi Jewish descent who have inherited the mutation from both parents.
What is the rs121908298 Variant?
The variant rs121908298, often referred to in clinical literature as c.2204+6T>C or IVS20+6T>C, is a specific change in the DNA sequence of the ELP1 gene (formerly known as IKBKAP). This variant is located near a splice site, which is a critical region that tells the cell how to assemble the final blueprint for a protein. By altering this site, the mutation disrupts the normal splicing process of the ELP1 gene's messenger RNA. This disruption leads to the production of a reduced amount of functional ELP1 protein, particularly in specific tissues like the brain. Because this variant is a single-point mutation that significantly impacts gene expression, it has been extensively studied in the context of hereditary conditions.
The Role of the ELP1 Gene
The ELP1 gene provides the instructions for creating a protein that acts as a scaffolding unit for the Elongator complex. This complex is involved in various cellular processes, including the regulation of gene expression and the development of the nervous system. In individuals with functional ELP1, the protein supports the growth, survival, and proper function of sensory and autonomic neurons. When the ELP1 protein is deficient, as seen in individuals who inherit two copies of the pathogenic mutation, the nervous system fails to develop or maintain itself correctly. This leads to the clinical features of familial dysautonomia, also known as Riley-Day syndrome, which includes difficulties with breathing, blood pressure regulation, temperature control, and sensory perception.
Research and Clinical Evidence
The evidence linking rs121908298 to familial dysautonomia is robust and well-established in clinical genetics. It is classified as a pathogenic founder mutation, meaning it is highly prevalent within a specific ancestral group due to historical genetic drift. Research indicates that this single variant accounts for approximately 99% of the disease-causing alleles in the Ashkenazi Jewish population. Because the condition is autosomal recessive, an individual must inherit two copies of the mutation—one from each parent—to manifest the symptoms of the syndrome. While the mutation is most common in individuals of Ashkenazi Jewish descent, it has been identified in compound heterozygous cases in other populations, where it is paired with a different mutation in the same gene.
Population Frequency
The rs121908298 variant is most frequently observed in individuals of Ashkenazi Jewish ancestry. Studies have consistently reported a carrier frequency of approximately 1 in 30 to 1 in 32 within this population. Because it is a recessive condition, being a carrier (having one copy of the variant) typically does not result in the symptoms of familial dysautonomia. However, the high carrier rate makes it a standard component of carrier screening panels for couples of Ashkenazi Jewish descent who are planning a pregnancy. In the general population outside of this specific ancestry, the variant is extremely rare.
What This Information Means for You
Understanding your carrier status for rs121908298 is primarily relevant for family planning. If you are a carrier, it means you have one copy of the variant, which does not cause the disease. However, if both parents are carriers, there is a 25% chance for each pregnancy that the child will inherit two copies of the mutation and develop familial dysautonomia. This information is not a medical diagnosis and does not predict your own health outcomes. If you have concerns about your genetic status or family history, it is essential to consult with a certified genetic counselor or a medical professional. They can provide context based on your specific ancestry and family history, and guide you through the implications of carrier screening results.
How common is this variant?
The carrier frequency for this variant is approximately 1 in 30 among individuals of Ashkenazi Jewish ancestry, while it is extremely rare in the general population.
Frequently asked questions
What is familial dysautonomia?
Familial dysautonomia, or Riley-Day syndrome, is a rare, inherited disorder that affects the development and survival of sensory and autonomic neurons. It leads to issues with basic bodily functions like blood pressure, temperature regulation, and pain sensitivity.
Do I need to be tested for rs121908298?
Carrier screening is typically recommended for individuals of Ashkenazi Jewish descent who are pregnant or planning a pregnancy. You should discuss the necessity of this test with your healthcare provider or a genetic counselor.
If I am a carrier, will I get sick?
No, being a carrier means you have one copy of the mutation, but you do not have the disease. Familial dysautonomia is an autosomal recessive condition, meaning it only manifests when an individual inherits two copies of the mutation.
Can this variant be treated?
There is no cure for familial dysautonomia, but there are treatments to manage the symptoms and improve quality of life. Research into gene-targeting therapies is ongoing, but these are not standard clinical treatments.
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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Founder splice-site mutation in ELP1/IKBKAP (c.2204+6T>C) conferring carrier status for familial dysautonomia (Riley-Day syndrome).
A classic splice-donor variant (c.2204+6T>C) in ELP1 (IKBKAP) leading to exon 20 skipping and determining carrier status for familial dysautonomia.
This variant is a primary mutation accounting for the majority of familial dysautonomia cases in Ashkenazi Jewish populations.