MEFV rs121908006: Understanding Carrier Status and FMF
The rs121908006 variant is a specific genetic change in the MEFV gene that results in a missense substitution known as p.Met694Ile. This variant is recognized as a marker for carrier status in familial Mediterranean fever (FMF), an autoinflammatory condition most frequently observed in North African Jewish and Arab populations.
What each genotype means
Typical MEFV genotype
This genotype represents the most common sequence for this position in the MEFV gene. It does not include the specific p.Met694Ile substitution associated with familial Mediterranean fever carrier status.
This is the most common genotype observed across all global populations.
Familial Mediterranean fever carrier
This genotype indicates you carry one copy of the p.Met694Ile variant, which is associated with carrier status for familial Mediterranean fever. While this condition is typically inherited in an autosomal recessive pattern, you should discuss the clinical implications of this carrier status with a genetic counselor or physician, especially if you have a family history of autoinflammatory symptoms.
This genotype is found at a low frequency, primarily observed in individuals of Middle Eastern and North African ancestry, with an allele frequency typically ranging from 0.005 to 0.015.
Potential familial Mediterranean fever
This genotype indicates you carry two copies of the p.Met694Ile variant. Because familial Mediterranean fever is an autoinflammatory condition, individuals with two variants in the MEFV gene may be at increased risk for symptoms such as recurrent fever and serositis; please consult with a medical professional for clinical evaluation and interpretation of your health status.
This genotype is very rare and is primarily identified in specific populations where the variant is more prevalent, such as North African Jewish and Arab communities.
What is the rs121908006 Variant?
The rs121908006 variant is a single nucleotide polymorphism (SNP) located within the MEFV gene. Specifically, it represents a c.2079A>G substitution, which leads to an amino acid change from methionine to isoleucine at position 694 (p.Met694Ile). This variant is categorized as a missense mutation, meaning the change in the DNA sequence alters the resulting protein's structure. In the context of genetic testing, this variant is often identified during screening for familial Mediterranean fever (FMF). Because FMF is typically inherited in an autosomal recessive pattern, identifying this variant helps determine carrier status. It is important to note that carrying a single copy of a variant associated with an autosomal recessive condition does not typically result in the full clinical expression of the disease, but it is a significant finding for family planning and genetic counseling purposes.
The Role of the MEFV Gene
The MEFV gene provides instructions for making a protein called pyrin. Pyrin is primarily expressed in white blood cells, specifically neutrophils, which are essential components of the immune system. The main function of pyrin is to regulate the inflammatory response by controlling the activation of the inflammasome, a complex that triggers the release of inflammatory cytokines like IL-1β. When the MEFV gene functions correctly, pyrin helps prevent unnecessary or excessive inflammation. However, certain mutations in this gene can disrupt the regulation of the inflammasome, leading to the recurrent, self-limiting episodes of fever and inflammation characteristic of familial Mediterranean fever. Research into MEFV continues to be a major focus in immunology, as understanding how these mutations affect pyrin function helps scientists develop better strategies for managing autoinflammatory conditions.
Research and Clinical Associations
Scientific literature identifies the MEFV gene as the primary site for mutations causing familial Mediterranean fever. While several variants in this gene are well-documented, rs121908006 is specifically noted for its presence in North African Jewish and Arab populations. Research indicates that FMF is an autoinflammatory disorder characterized by recurrent episodes of fever, peritonitis, pleuritis, and arthritis. The evidence linking specific MEFV variants to FMF is strong, though the clinical impact of any single variant can vary based on the presence of other mutations. Because FMF is autosomal recessive, individuals who are carriers (having one variant copy) are generally asymptomatic. However, the presence of this variant is a critical piece of information for clinicians when evaluating patients with symptoms of unexplained inflammation. As with all genetic findings, the clinical significance of this variant should be discussed with a healthcare provider or a genetic counselor who can interpret the results within the context of an individual's full medical and family history.
Population Frequency and Distribution
The frequency of MEFV variants varies significantly across different global populations, with the highest prevalence found in groups originating from the Mediterranean basin. According to data from the Genome Aggregation Database (gnomAD), the allele frequency for rs121908006 in Middle Eastern and African populations is estimated to be between 0.005 and 0.015. These frequencies reflect the historical genetic drift and founder effects that have influenced the distribution of FMF-related variants in these regions. Because these variants are more common in specific ancestral groups, genetic screening programs often prioritize these populations. It is important to remember that population-level statistics provide a broad overview and do not predict the specific genetic makeup of any single individual. Understanding these frequencies helps researchers track the evolution of the gene and assists clinicians in assessing the likelihood of carrier status in patients from these specific backgrounds.
What You Can Do With This Information
If you have received information regarding your status for the rs121908006 variant, the most important step is to consult with a qualified healthcare professional or a genetic counselor. This information is primarily used for carrier screening and family planning. Because this variant is associated with an autosomal recessive condition, being a carrier does not mean you have the disease, but it does mean there is a possibility of passing the variant to your children. You should not use this information to make medical decisions or to diagnose yourself with any condition. If you are experiencing symptoms such as recurrent fevers or unexplained inflammation, share your genetic report with your doctor, who can order appropriate clinical testing and provide a formal evaluation. Genetic information is complex, and a professional can help you understand what these results mean for your health and your family's future.
How common is this variant?
The rs121908006 variant is most common in Middle Eastern and North African populations, with an allele frequency typically ranging from 0.005 to 0.015 in these groups.
Frequently asked questions
What is familial Mediterranean fever?
Familial Mediterranean fever (FMF) is an inherited autoinflammatory disorder that causes recurrent episodes of fever, abdominal pain, and joint inflammation. It is caused by mutations in the MEFV gene and is most common in people of Mediterranean, Middle Eastern, and North African descent.
Does having this variant mean I have FMF?
Not necessarily. FMF is an autosomal recessive condition, meaning it usually requires two copies of a disease-causing mutation to manifest symptoms. If you only have one copy, you are considered a carrier and are typically asymptomatic.
Should I get tested for FMF if I am a carrier?
If you are a carrier or have a family history of FMF, you may want to speak with a genetic counselor. They can help you understand your risk and determine if further clinical testing is appropriate based on your personal health history.
Is there a cure for FMF?
While there is no cure for FMF, it is a manageable condition. Treatments, such as daily medication, are highly effective at preventing the recurrent inflammatory episodes and long-term complications like amyloidosis. Always consult your physician for personalized medical advice.
Sources & further reading
Educational information only, last refreshed 9/24/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Pathogenic missense variant in MEFV (p.Val726Ala) conferring carrier status or reduced-penetrance familial Mediterranean fever.
A missense mutation (c.2080A>G, p.Met694Val) in pyrin, a well-established pathogenic variant for familial Mediterranean fever (FMF) with high penetrance.
A missense variant (c.2040G>C, p.Met680Ile) in pyrin conferring carrier status for familial Mediterranean fever, widely observed across Eastern Mediterranean cohorts.
A missense substitution (c.2177T>C, p.Val726Ala) in MEFV establishing carrier status for autosomal recessive familial Mediterranean fever, common in Armenian and Arab lineages.
A missense substitution (c.1984G>A, p.Glu66Lys, often referred to as E148Q) associated with reduced penetrance for familial Mediterranean fever.
Carrier variant for Familial Mediterranean Fever (p.Met694Val), conferring carrier status for recurrent autoinflammatory febrile episodes.