Periodic Fever Syndrome Genetic Panel: Autoinflammatory Genes and Results

A periodic fever syndrome genetic panel looks for inherited or newly occurring variants in genes that regulate innate immunity and inflammation. It can help diagnose monogenic autoinflammatory conditions such as familial Mediterranean fever, mevalonate kinase deficiency, TNF receptor–associated periodic syndrome, and cryopyrin-associated periodic syndromes. A positive pathogenic result can guide treatment, complication screening, family testing, and inheritance counseling. A negative result does not rule out an autoinflammatory disorder because some conditions are polygenic, mosaic, not yet genetically defined, or outside the panel’s technical reach. A variant of uncertain significance is not a diagnosis and should not direct treatment without supporting clinical evidence. The most useful evaluation combines the genetic result with the age attacks began, fever duration, symptom pattern, inflammatory markers during and between episodes, ancestry, family history, infection evaluation, and response to therapy. Testing usually requires blood or saliva and needs no fasting, though blood may be preferred when low-level mosaicism is suspected.

• A pathogenic variant can confirm a specific hereditary fever syndrome when the symptoms and inheritance pattern fit.
• A negative panel does not exclude PFAPA, undifferentiated autoinflammation, low-level mosaicism, or a gene not included in the assay.
• A variant of uncertain significance should not be treated as disease-causing until stronger evidence emerges.
• Testing is most informative when fever episodes are documented with dates, duration, associated symptoms, and CRP or serum amyloid A levels.
• Seek urgent care for fever with severe illness, breathing difficulty, stiff neck, confusion, dehydration, or signs of sepsis rather than assuming an inherited flare.

Table of Contents

• What a periodic fever panel tests
• Common conditions and genes
• Who may benefit from testing
• Sample collection and test methods
• How to interpret positive, negative, and uncertain results
• How genetics fits with the clinical diagnosis
• Inheritance and family testing
• Next steps and long-term follow-up

What a periodic fever panel tests

Periodic fever syndromes are disorders in which the innate immune system triggers repeated episodes of inflammation without the usual infection or autoantibody-driven cause. Fever may occur with abdominal or chest pain, rash, mouth sores, swollen glands, eye inflammation, joint pain, muscle pain, headaches, hearing changes, or other features.

A panel analyzes several genes at once because symptoms overlap. Most laboratories use next-generation sequencing to examine coding regions and nearby splice sites. Many also test for exon-level deletions or duplications. Larger panels may include dozens or hundreds of autoinflammatory and immune-dysregulation genes.

The panel does not test “fever” itself. It looks for DNA variants that can disrupt inflammasomes, cytokine pathways, protein folding, cell death, metabolism, or other innate immune functions. The exact gene list differs by laboratory, so two tests with the same name may not be equivalent.

A focused panel may include MEFV, MVK, TNFRSF1A, and NLRP3. An expanded panel may add genes such as NLRC4, NOD2, PSTPIP1, IL1RN, IL36RN, ADA2, LPIN2, PSMB8, OTULIN, TNFAIP3, RIPK1, WDR1, and many others. Some panels include genes for cyclic neutropenia, immune deficiency, hemophagocytic lymphohistiocytosis, or interferonopathies because these conditions can resemble periodic fever.

Before ordering, review:

• the complete gene list;
• whether deletion and duplication analysis is included;
• whether mitochondrial, deep intronic, repeat, or structural variants are detectable;
• the laboratory’s ability to detect mosaic variants below 20% allele fraction;
• whether parental samples can be tested;
• whether the report follows current variant-classification standards.

A multigene panel test increases efficiency but also increases the chance of uncertain or incidental findings. The widest panel is not automatically the best; phenotype-guided selection improves interpretation.

Common conditions and genes

Several classic hereditary recurrent fever syndromes have recognizable but overlapping patterns.

Condition	Main gene	Typical pattern	Common inheritance
Familial Mediterranean fever	MEFV	Attacks often last 1–3 days with fever, abdominal or chest pain, arthritis, or erysipelas-like rash	Usually autosomal recessive, with important exceptions
Mevalonate kinase deficiency	MVK	Fever with lymph nodes, abdominal symptoms, rash, mouth ulcers, or joint pain; attacks may follow vaccines or stress	Autosomal recessive
TNF receptor–associated periodic syndrome	TNFRSF1A	Longer attacks, migratory rash, severe muscle pain, abdominal pain, or swelling around the eyes	Autosomal dominant
Cryopyrin-associated periodic syndromes	NLRP3	Cold-triggered or persistent urticaria-like rash, fever, joint symptoms, hearing loss, or neurologic inflammation	Autosomal dominant; mosaicism is common in some later-onset cases
Deficiency of adenosine deaminase 2	ADA2	Fever, livedo, strokes, vasculitis, cytopenias, or immune deficiency	Autosomal recessive
PAPA syndrome	PSTPIP1	Sterile arthritis, severe acne, and pyoderma gangrenosum	Autosomal dominant

Other genes cause severe early-onset inflammation, bowel disease, pustular skin disease, recurrent macrophage activation, sterile bone inflammation, or interferon-driven disease. The phenotype can broaden as new patients are recognized.

PFAPA—periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis—is common in children with regular episodes, but no single diagnostic gene explains most cases. PFAPA can cluster in families and may have polygenic contributors. A negative periodic fever panel is therefore expected in many clinically typical PFAPA cases.

Cyclic neutropenia can mimic periodic fever and is often related to ELANE variants. A complete blood count repeated two or three times weekly for about six weeks may reveal the cycling pattern more directly than a one-time count.

Who may benefit from testing

Testing is most helpful when the history suggests a monogenic autoinflammatory disorder. Features that raise the yield include:

• onset in infancy or childhood;
• repeated episodes with a similar duration and symptom pattern;
• elevated C-reactive protein, erythrocyte sedimentation rate, or serum amyloid A during attacks;
• persistent inflammation between attacks;
• rash, serositis, aseptic meningitis, hearing loss, vasculitis, severe mouth ulcers, sterile bone inflammation, or unexplained cytopenias;
• several affected relatives;
• ancestry associated with a founder variant, while recognizing that any ancestry can be affected;
• unexplained kidney protein, amyloidosis, or growth impairment;
• poor fit with infection, malignancy, autoimmune disease, and PFAPA;
• a treatment response characteristic of a pathway, such as colchicine response in suspected FMF.

Testing may have lower yield when fevers are irregular, clearly infectious, or accompanied by normal inflammatory markers and no consistent features. That does not mean symptoms are unimportant; it means other evaluations may be more informative first.

Before genetic testing, clinicians often review infection history, medication use, travel, immunization, inflammatory markers, blood counts, liver and kidney function, urinalysis, immunoglobulins, autoantibodies when appropriate, and imaging or specialist findings. Malignancy and immune deficiency can produce recurrent fever and must not be overlooked.

A fever diary improves interpretation. Record the date, maximum temperature, duration, associated symptoms, triggers, medication response, and whether the person is completely well between episodes. Photographs of rash or swelling and laboratory tests during an attack can be valuable.

Urgent illness should be evaluated as urgent illness. A known periodic fever syndrome does not protect a person from pneumonia, appendicitis, meningitis, sepsis, or another emergency.

Sample collection and test methods

Blood is the most common sample, though saliva or cheek cells may be accepted. No fasting is needed. Anti-inflammatory drugs and biologics do not alter germline DNA, but they can change symptoms and laboratory inflammation.

Blood may be preferable when low-level somatic mosaicism is suspected. Mosaicism means a pathogenic variant arose after conception and is present in only a portion of cells. NLRP3 and other autoinflammatory genes can cause disease through mosaic variants that standard germline pipelines may miss. Testing another tissue or using deep sequencing may be needed.

Most panels use next-generation sequencing. Confirmatory Sanger sequencing may be performed for selected variants, though it is less sensitive for low-level mosaicism. Copy-number analysis detects larger exon deletions or duplications. Exome or genome sequencing may be considered when a panel is negative and suspicion remains high.

Technical blind spots can include:

• deep intronic variants;
• balanced rearrangements;
• repeat expansions;
• complex structural changes;
• low-level mosaicism below the assay threshold;
• variants in poorly covered exons;
• genes discovered after the panel was designed;
• epigenetic or multifactorial disease.

The report should state coverage and limitations. A “negative” test means no reportable variant was found by that method, not that every possible genetic cause was excluded.

Some MEFV assays historically tested only common founder variants. Full-gene sequencing is more informative in atypical ancestry or presentation, although even comprehensive testing cannot replace clinical judgment in FMF.

How to interpret positive, negative, and uncertain results

A pathogenic or likely pathogenic variant can establish a molecular diagnosis when the gene, inheritance pattern, and symptoms fit. In a dominant condition, one disease-causing variant may be sufficient. In a recessive condition, two pathogenic variants usually need to be found on opposite chromosome copies, called in trans.

A person with two variants in a recessive gene may need parental testing to determine phase. If both variants came from one parent and sit on the same chromosome, the other gene copy may be unaffected. Phase can change the diagnosis.

A variant of uncertain significance, or VUS, has insufficient evidence for or against a disease-causing role. It should not be used alone to label a child, start lifelong treatment, predict relatives’ health, or make reproductive decisions. Evidence can change as population databases, functional studies, and case reports grow.

A negative result has several meanings. The symptoms may be caused by a nongenetic condition, a polygenic syndrome such as many PFAPA cases, an untested gene, a variant the method cannot detect, or a currently unknown mechanism. Clinical diagnosis can still be valid for FMF or another syndrome in selected patients without a definitive genotype.

A single pathogenic MEFV or MVK variant requires nuance. One variant in a recessive gene may indicate carrier status, but some MEFV variants show variable or dominant-like effects, and symptomatic heterozygotes occur. The allele, ancestry, phenotype, and expert assessment matter.

A result may also reveal a low-penetrance or risk allele. Such variants can modify inflammation without acting like fully penetrant mutations. Laboratories should distinguish them from classic pathogenic variants.

The pathogenic, benign, and VUS categories describe evidence, not symptom severity. A pathogenic result can cause mild disease in one person and severe disease in another.

How genetics fits with the clinical diagnosis

Periodic fever diagnosis begins with the pattern. Attack duration, symptom combinations, triggers, and wellness between episodes can point toward a pathway. Genetics can confirm or refine that impression, but discordant findings require reassessment.

Inflammatory markers should be checked during attacks when possible. CRP and serum amyloid A usually rise in active autoinflammation. Persistent serum amyloid A elevation matters because chronic inflammation can lead to AA amyloidosis, especially in untreated FMF and some TRAPS cases. Urine protein and kidney function help screen for this complication.

Treatment response can support but not prove a diagnosis. Colchicine often prevents FMF attacks and amyloidosis. Interleukin-1 blockers can be highly effective in cryopyrin-associated syndromes and several other conditions. TNF or interleukin-6 blockade has roles in selected diseases. Steroids may shorten PFAPA attacks but can also shorten the interval to the next episode.

Do not use a short medication trial as a substitute for excluding infection or malignancy. Biologics suppress immunity and require a firm specialist plan, vaccination review, and infection screening.

Ancestry is helpful but should not restrict testing. FMF is more frequent in Armenian, Turkish, Arab, Jewish, North African, and Mediterranean populations, yet it occurs worldwide. TRAPS and CAPS likewise affect diverse families.

A periodic fever panel may uncover a condition whose main feature is not fever, such as immune deficiency, vasculitis, or bowel inflammation. Results should be reviewed by pediatric rheumatology, adult rheumatology, clinical immunology, or medical genetics according to the presentation.

Inheritance and family testing

Autosomal dominant conditions generally require one pathogenic variant. An affected parent has a 50% chance of passing that variant to each child, but penetrance and severity can vary. A new, or de novo, variant can arise in a child with unaffected parents.

Autosomal recessive conditions generally require pathogenic variants in both gene copies. When both parents carry one variant in the same gene, each pregnancy has a 25% chance of an affected child, a 50% chance of a carrier, and a 25% chance of a child with neither familial variant.

X-linked, mitochondrial, digenic, and mosaic inheritance can occur in expanded panels. The laboratory and genetic counselor should explain the specific result rather than applying a generic rule.

Testing relatives is most informative after a familial pathogenic variant is identified. Testing only the known variant is usually faster and easier to interpret than repeating a broad panel. Healthy relatives with the variant may need evaluation because penetrance can be incomplete.

A VUS should not usually be used for predictive testing of healthy relatives, although carefully selected family studies may help the laboratory determine whether it tracks with symptoms. Carrier testing and reproductive options can be discussed for confirmed recessive conditions.

Family history may appear negative because the variant is new, relatives were misdiagnosed, symptoms were mild, family size is small, or recessive carriers are healthy. Lack of family history does not exclude a genetic syndrome.

Next steps and long-term follow-up

Review the full report with the ordering specialist or a genetic counselor. Confirm the variant, classification, inheritance, panel coverage, and whether parental testing or biochemical confirmation is recommended.

For a positive diagnosis, follow disease-specific monitoring. This may include serum amyloid A, CRP, urine protein, kidney and liver tests, hearing tests, eye examination, neurologic assessment, blood counts, growth monitoring, or vaccination planning. Treatment should target the pathway and complication risk rather than fever alone.

For a VUS, continue clinical care based on symptoms. Ask whether the laboratory offers reanalysis and how updates will be communicated. Reclassification can take years and may move toward benign as often as toward pathogenic.

For a negative result with strong suspicion, options include panel reanalysis, a broader panel, exome or genome sequencing, mosaic testing, RNA studies, or referral to a specialty center. Repeating an identical test immediately is rarely useful.

Maintain a plan for ordinary fever. The clinician should define which symptoms can be managed as a familiar flare and which require infection testing or emergency care. New focal pain, breathing difficulty, severe lethargy, neck stiffness, dehydration, low blood pressure, or a different fever pattern deserves prompt assessment.

Distinguishing attack patterns

Attack timing can narrow the differential before sequencing. FMF attacks are often short, with sharp abdominal or chest pain from serosal inflammation. TRAPS episodes often last longer and may include migrating muscle pain, rash, or swelling around the eye. Mevalonate kinase deficiency can produce cervical lymph nodes, diarrhea, vomiting, mouth ulcers, and attacks after vaccination or stress. Cryopyrin-associated disease often combines an urticaria-like rash with cold sensitivity, hearing loss, eye findings, or persistent inflammation.

These patterns overlap and are not rigid rules. Young children may not describe pain accurately, treatments can shorten attacks, and a person can have more than one condition. A diary covering several untreated or minimally treated episodes is more useful than remembering one dramatic fever.

PFAPA often begins before age five and has strikingly regular episodes of fever with mouth ulcers, sore throat, and neck nodes. Children are usually well between attacks and grow normally. Infections can mimic PFAPA, and a child with recurrent bacterial tonsillitis needs a different approach. Genetic testing is generally used when the pattern is atypical, severe, familial, persistent into adulthood, or accompanied by features outside PFAPA.

Laboratory monitoring beyond CRP

A normal CRP between attacks can support a periodic pattern, while persistent elevation raises concern for ongoing inflammation, another autoinflammatory disease, infection, inflammatory bowel disease, or malignancy. Serum amyloid A is particularly useful when available because continued elevation predicts risk of AA amyloid deposition.

Urinalysis and urine protein-to-creatinine ratio can detect early kidney involvement from amyloidosis. Creatinine may remain normal until later, so urine screening matters. Complete blood count can reveal neutropenia, anemia, thrombocytopenia, or leukocytosis that points toward another pathway.

Ferritin, liver enzymes, triglycerides, fibrinogen, and soluble interleukin-2 receptor may be used when macrophage activation syndrome or hemophagocytic lymphohistiocytosis is suspected. These are urgent inflammatory states and should not wait for panel results.

Treatment implications of selected diagnoses

A confirmed MEFV-related FMF diagnosis supports regular colchicine, which prevents attacks and greatly reduces amyloidosis risk. Adherence is important even when attacks improve. Persistent inflammation despite an adequate tolerated dose may lead to interleukin-1 therapy under specialist care.

NLRP3-associated cryopyrin disease often responds dramatically to interleukin-1 blockade, and early treatment can protect hearing, the nervous system, joints, and kidneys. TRAPS treatment may also use interleukin-1 inhibition; prolonged steroid dependence is generally undesirable. Mevalonate kinase deficiency management depends on severity and may include biologic treatment.

Genotype can sometimes inform expected severity, but phenotype remains decisive. Low-penetrance variants should not trigger lifelong biologics in a person whose symptoms do not fit. Conversely, a severely affected person may require treatment while molecular testing remains unresolved.

Vaccination and infection plans should be reviewed before biologic therapy. Families should know that fever after starting immune-modifying treatment could be an infection, not merely a flare.

A normal temperature recorded at one clinic visit does not weaken a well-documented recurrent pattern. Many patients are completely well between attacks. Conversely, fever every day for weeks may point toward chronic infection, malignancy, systemic inflammatory disease, or a severe autoinflammatory condition rather than a classic periodic syndrome.

The clinical team should periodically revisit the diagnosis when the pattern changes. New neurologic symptoms, hearing loss, persistent protein in urine, growth failure, or inflammation between attacks can signal progression or a different disorder and may justify expanded testing.

A child’s growth chart and school attendance can provide objective evidence of disease burden even when attacks are not witnessed in clinic.

References

• Updates in the Management of Hereditary Periodic Fever Syndromes 2025 (Review)
• EULAR/PReS endorsed recommendations for the management of familial Mediterranean fever (FMF): 2024 update 2025 (Guideline)
• Autoinflammatory Diseases: A Review 2024 (Review)
• The riddle of recurrent fever: a clinical approach to pediatric autoinflammatory diseases 2024 (Review)
• Predictive Clinical and Biological Criteria for Gene Panel Positivity in Suspected Inherited Autoinflammatory Diseases 2023
• Guidelines for the genetic diagnosis of hereditary recurrent fevers 2012 (Guideline)

Disclaimer

This article provides general information and cannot diagnose a periodic fever syndrome or distinguish an inherited flare from an acute infection. Genetic results require interpretation with the clinical pattern, inflammatory markers, and specialist evaluation. Seek urgent medical care for severe or unusual fever symptoms, and do not start colchicine, steroids, biologics, or other treatment based only on a genetic report.