TNF Receptor-Associated Periodic Syndrome

1. Disease Information

Overview. TNF receptor-associated periodic syndrome (TRAPS) is the prototypic autosomal-dominant monogenic autoinflammatory disease (hereditary periodic fever syndrome), caused by heterozygous mutations in TNFRSF1A, the gene encoding the 55-kDa type 1 receptor for tumor necrosis factor (TNFR1/p55/CD120a). Clinically it is defined by recurrent, self-limited inflammatory attacks — fever, migratory myalgia with overlying rash, abdominal pain (sterile peritonitis), periorbital edema, conjunctivitis, and arthralgia — that characteristically last longer than the attacks of other periodic fevers (often 1–3 weeks), separating it from familial Mediterranean fever (FMF, attacks 1–3 days) and the cryopyrinopathies. The most feared long-term complication is systemic AA (reactive) amyloidosis.

Think of TNFR1 here like a smoke detector wired backwards: instead of quietly waiting at the cell surface for a real fire (TNF), the mutant receptor gets jammed inside the cell's "shipping department" and starts setting off the alarm on its own.

It was first delineated genetically in 1999, unifying several previously eponymous disorders — most famously "familial Hibernian fever" described in a large Irish/Scottish kindred — under a single molecular cause.

"In seven affected families, we found six different missense mutations of the 55 kDa TNF receptor (TNFR1), five of which disrupt conserved extracellular disulfide bonds. Soluble plasma TNFR1 levels in patients were approximately half normal." — McDermott et al., Cell 1999 (PMID:10199409)

Key identifiers: | Resource | Identifier | |---|---| | MONDO | MONDO:0019751 (TNF receptor associated periodic syndrome) | | OMIM | 142680 (TNF RECEPTOR-ASSOCIATED PERIODIC SYNDROME; TRAPS) | | Orphanet | ORPHA:32960 | | ICD-11 | 4A60.23 (Tumour necrosis factor receptor 1 associated periodic syndrome) | | ICD-10 | No dedicated code; coded under M04.1 (periodic fever syndromes) / D89.8 | | MeSH | No standalone descriptor; indexed under Hereditary Autoinflammatory Diseases (D056660) | | Gene (HGNC) | TNFRSF1A, hgnc:11916 |

Synonyms / alternative names: TRAPS; TNF receptor-associated periodic fever syndrome; Familial Hibernian fever (FHF); Hibernian fever; Autosomal dominant familial periodic fever; Familial periodic fever, autosomal dominant; TNFRSF1A-associated periodic syndrome; periodic fever, familial, autosomal dominant.

Data derivation: Disease-level knowledge here is aggregated from curated resources (OMIM, Orphanet, GeneReviews) and from patient-level cohort data, most notably the Eurofever/EUROTRAPS international registry (158 validated cases) — i.e., this is registry/cohort-aggregated rather than EHR-derived.

2. Etiology

Primary cause (genetic). TRAPS is monogenic: heterozygous gain-of-function/misfolding missense mutations in TNFRSF1A, located predominantly in the extracellular cysteine-rich domains (CRD1 and CRD2) of TNFR1. Mutations that disrupt conserved disulfide bonds (e.g., cysteine substitutions, T50M) confer the highest penetrance and severity.

Triggers of attacks (environmental/physiologic modifiers). Individual flares are often precipitated by physical or psychological stress, minor infection, trauma, fatigue, hormonal changes (menstruation), exercise, and vaccination — but the underlying disease is genetic, and these are flare triggers, not causes.

Risk factors - Genetic risk factors: - Causal/high-penetrance variants: cysteine substitutions (C30R, C43R, C52F, C88Y, etc.) and T50M — strongly associated with disease persistence into adulthood and amyloidosis. - Low-penetrance susceptibility variants: R92Q (c.362G>A; legacy nomenclature; corresponds to p.Arg121Gln with signal peptide) and P46L (p.Pro75Leu). These are common in the general population, behave as susceptibility/modifier alleles rather than fully penetrant disease alleles, and produce milder, sometimes self-limited phenotypes. In the Eurofever cohort, R92Q accounted for ~34% of cases and T50M ~10%, with family history present in only 19% of R92Q carriers vs 64% of those with other variants (Lachmann et al., PMID:23965844). - Family history: a first-degree affected relative is a major risk factor given autosomal-dominant transmission. - Environmental risk factors: No environmental exposure causes TRAPS; ethnicity influences variant frequency (R92Q and P46L vary by population — P46L is notably more frequent in individuals of West/sub-Saharan African ancestry).

Protective factors. None specifically established genetically. Effective continuous anti-inflammatory therapy is "protective" against the development of amyloidosis (see §11–12). No dietary or lifestyle protective factor is validated.

Gene–environment interactions. The clearest interaction is stress/infection/trauma acting on a genetically primed innate immune system to precipitate flares. For low-penetrance alleles (R92Q/P46L), phenotype is thought to emerge only with additional genetic or environmental "second hits," explaining incomplete penetrance.

3. Phenotypes

For each, I give type, characteristics, and a suggested HP term. Frequencies are drawn primarily from the Eurofever/EUROTRAPS registry (Lachmann 2014, PMID:23965844) and Aksentijevich 2001 (PMID:11443543, Am J Hum Genet 69:301–314 — verify exact digits before commit).

Laboratory abnormalities (acute-phase reaction during flares): | Lab phenotype | Suggested HP term | |---|---| | Elevated C-reactive protein | HP:0011227 Increased C-reactive protein level | | Elevated ESR | HP:0003565 Elevated erythrocyte sedimentation rate | | Leukocytosis / neutrophilia | HP:0001974 Leukocytosis | | Reactive thrombocytosis | HP:0001894 Thrombocytosis | | Anemia of chronic disease | HP:0001903 Anemia | | Elevated serum amyloid A (SAA) | (use elevated acute-phase reactant) | | Polyclonal hypergammaglobulinemia / elevated IgD (modest) | HP:0010702 (IgD elevation — verify) |

Phenotype characteristics: - Onset: typically childhood (median ~4 years) but a wide range, with adult-onset (even after age 50) well documented, especially for low-penetrance variants. - Severity: variable, strongly genotype-influenced — cysteine/T50M variants severe; R92Q/P46L mild. - Progression: episodic/recurrent with symptom-free intervals; attacks recur every ~4–6 weeks, lasting (per GeneReviews) "between five and 25 days." Subclinical inflammation can persist between attacks, driving amyloidosis. - Quality-of-life impact: Recurrent prolonged attacks cause significant school/work absenteeism, chronic pain, fatigue, and impaired daily functioning; amyloidosis can progress to chronic kidney disease and dialysis dependence. (No TRAPS-specific validated QoL instrument; generic SF-36/EQ-5D and the AIDAI [Autoinflammatory Diseases Activity Index] are used in autoinflammatory cohorts.)

4. Genetic / Molecular Information

Causal gene. TNFRSF1A (TNF receptor superfamily member 1A), HGNC: hgnc:11916, located at chromosome 12p13.31; OMIM gene 142680; encodes TNFR1 (p55, CD120a), UniProt P19438. NCBI Gene ID 7132; Ensembl ENSG00000067182.

Pathogenic variants. - Location: clustered in exons 2–4, encoding the extracellular cysteine-rich domains CRD1 and CRD2. - Variant type/class: predominantly missense; a large fraction are cysteine substitutions that abolish one of the conserved disulfide bonds essential for correct folding of the CRDs. Splice and small in-frame changes are rare. No large deletions or whole-gene CNVs are characteristic — this is a coding-missense disease. - Representative high-penetrance variants: C30R, C30S, C33Y, C43R, T50M, C52F, C70R/C70Y, C88R/C88Y, etc. - Low-penetrance variants: R92Q (c.362G>A) and P46L — present at appreciable allele frequency in gnomAD (R92Q ~1% in some populations; P46L higher in African-ancestry groups), consistent with reduced penetrance and a susceptibility-allele model. - Origin: germline (autosomal dominant); de novo mutations occur. No somatic mechanism. - Functional consequence: Mechanistically a misfolding / aberrant gain-of-function (NOT simple haploinsufficiency or classical loss of TNF signaling) — see §6. Original "shedding hypothesis" (impaired cleavage of TNFR1 from the cell surface leaving membrane receptor to signal unopposed) has been superseded/complemented by the misfolding/ER-retention model.

Aksentijevich et al. confirmed and expanded the mutational spectrum and population genetics: "mutations in the extracellular domain of the 55-kD tumor-necrosis factor (TNF) receptor (TNFRSF1A) define TRAPS" (PMID:11443543, Am J Hum Genet 2001 — verify digits).

Variant classification (ACMG/AMP). Cysteine and T50M variants are generally curated Pathogenic/Likely pathogenic in ClinVar; R92Q and P46L are typically classified as "risk factor" / reduced-penetrance / conflicting rather than straightforwardly pathogenic.

Modifier genes. Not well defined. Genetic background and possibly other innate-immunity loci modulate penetrance, particularly for R92Q/P46L; co-inheritance with MEFV (FMF) variants has been reported to modify phenotype in individual cases.

Epigenetic information. No established disease-defining epigenetic signature. Inflammation-associated changes are secondary.

Chromosomal abnormalities. None characteristic — TRAPS is a single-nucleotide/missense disorder, not a structural/aneuploidy disorder.

5. Environmental Information

• Environmental factors: No toxin, radiation, or pollutant is causal. Flares are precipitated by nonspecific stressors (see §2).
• Lifestyle factors: Physical exertion, emotional stress, and fatigue are reported flare triggers; no lifestyle factor causes or cures the disease.
• Infectious agents: No causative pathogen. Intercurrent infections can trigger flares and complicate the differential diagnosis, but TRAPS is sterile (non-infectious) autoinflammation; "sterile peritonitis" is a defining feature.

6. Mechanism / Pathophysiology

TRAPS sits at the intersection of TNF signaling, ER protein-folding quality control, mitochondrial ROS, and innate cytokine amplification. The current integrated model:

Causal chain (upstream → downstream):

1. Mutant TNFR1 misfolds because disulfide-bond–disrupting (cysteine) or destabilizing (T50M) substitutions prevent correct folding of the extracellular CRDs.
2. Misfolded receptor is retained in the endoplasmic reticulum rather than trafficking to the cell surface; it forms abnormal disulfide-linked oligomers that cannot engage wild-type receptor via the pre-ligand assembly domain (PLAD).

"TRAPS mutant TNFR1 molecules were retained intracellularly and colocalized with endoplasmic reticulum markers... The inflammatory phenotype of TRAPS may be due to consequences of mutant TNFR1 protein misfolding and ER retention." — Lobito et al., Blood 2006 (PMID:16684962)

1. ER stress / unfolded protein response (UPR) is activated by the accumulated misfolded receptor.
2. Elevated mitochondrial reactive oxygen species (mtROS) result, lowering the threshold for innate immune activation and enhancing pro-inflammatory cytokine production (especially in response to LPS).

"Mitochondrial ROS... promote production of proinflammatory cytokines and are elevated in TNFR1-associated periodic syndrome (TRAPS)... ROS generated by mitochondrial respiration are important for... the enhanced responsiveness to LPS seen in cells from patients with TRAPS." — Bulua et al., J Exp Med 2011 (PMID:21282379)

1. Constitutive/augmented activation of NF-κB and MAPK (JNK/p38) signaling, plus defective autophagy of mutant receptor, sustains an inflammatory state. Some surface-retained mutant receptor signals in a ligand-independent manner.
2. Amplified secretion of IL-1β (and IL-6, TNF) drives the clinical attacks. The dramatic efficacy of IL-1 blockade is the clinical proof that IL-1β is the dominant downstream effector (CLUSTER trial, §12).
3. Chronic/subclinical inflammation → sustained elevation of serum amyloid A (SAA) → AA amyloid fibril deposition, predominantly in the kidney (renal amyloidosis → proteinuria/nephrotic syndrome → renal failure).

A "concerted action" of wild-type and mutant receptors enhancing inflammation has also been proposed (Simon et al., PNAS 2010 — PMID ~20133695; verify before commit).

Molecular pathways (suggested annotations): - TNF-mediated signaling pathway — GO:0033209 - I-κB kinase/NF-κB signaling — GO:0007249 - MAPK cascade — GO:0000165 - Response to endoplasmic reticulum stress / UPR — GO:0034976; cellular response to unfolded protein — GO:0034620 - Reactive oxygen species metabolic process — GO:0072593 - Inflammatory response — GO:0006954 - Interleukin-1 beta production — GO:0032611 - Autophagy — GO:0006914 (impaired clearance of mutant receptor) - Protein folding — GO:0006457

Cellular processes: ER-stress signaling, mitochondrial ROS generation, NLRP3 inflammasome priming/activation, defective autophagy, ligand-independent receptor signaling, enhanced innate cytokine secretion.

Protein dysfunction: misfolding + aggregation + intracellular (ER) retention of TNFR1 → aberrant gain of pro-inflammatory function. UniProt P19438; structural basis in the cysteine-rich TNFR ectodomain (PDB structures of TNFR1 ectodomain, e.g., 1NCF/1EXT).

Immune system involvement: This is an innate-immune (autoinflammatory) disease — monocytes/macrophages and neutrophils are central; it is not classically autoimmune (no defining autoantibody, no HLA-restricted T-cell autoimmunity).

Tissue damage mechanisms: acute neutrophilic/monocytic inflammation of fascia, serosa, skin, synovium; chronic damage via AA amyloid fibril deposition (oxidative/proteotoxic, see amyloid).

Molecular profiling: Patient PBMCs/monocytes show elevated baseline mtROS, augmented LPS-induced cytokines, ER-stress transcriptional signatures, and altered metabolism (a "metabolic signature" of TNFRSF1A mutation has been reported — see Frontiers/PubMed 36752501).

Cell types (suggested CL terms): monocyte CL:0000576; macrophage CL:0000235; neutrophil CL:0000775; fibroblast CL:0000057 (fasciitis); endothelial cell CL:0000115.

7. Anatomical Structures Affected

Organ/system level: - Skin and subcutaneous tissue / fascia (UBERON: skin UBERON:0002097; fascia UBERON:0007798) — migratory erythematous rash overlying painful muscle. - Skeletal muscle (UBERON:0001134) — myalgia from monocytic fasciitis. - Serous membranes / peritoneum (peritoneum UBERON:0002358; pleura UBERON:0000977) — sterile peritonitis, pleuritis. - Eye / periorbital region (conjunctiva UBERON:0001811; orbital region UBERON:0001697) — conjunctivitis, periorbital edema. - Joints / synovium (synovial joint UBERON:0002217) — arthralgia/arthritis. - Kidney (UBERON:0002113) — the principal target of AA amyloidosis. - Reticuloendothelial system — lymphadenopathy, splenomegaly (spleen UBERON:0002106; lymph node UBERON:0000029). - Systems involved: musculoskeletal, integumentary, gastrointestinal/serosal, ophthalmic, renal/genitourinary, hematologic/immune.

Tissue/cell level: inflammatory infiltration of fascia (monocytic fasciitis), dermis (perivascular mononuclear infiltrate), serosa, and synovium; amyloid deposition in renal glomeruli/interstitium.

Subcellular level (GO cellular component): - Endoplasmic reticulum — GO:0005783 (site of mutant-receptor retention) - Mitochondrion — GO:0005739 (source of pathogenic ROS) - Plasma membrane — GO:0005886 (TNFR1 normal locale) - Autophagosome — GO:0005776

Localization/lateralization: systemic; cutaneous/muscular manifestations are often migratory and may be unilateral at any moment but are not fixed-sided; serositis and amyloidosis are systemic/bilateral.

8. Temporal Development

• Onset: typically childhood, median around 4 years, but described from infancy to >50 years (later onset more common with R92Q/P46L). Onset pattern is acute, recurrent.
• Disease course: episodic/recurrent-remittent. Discrete attacks of fever + serositis + myalgia/rash recurring at irregular intervals (~every 4–6 weeks), each lasting ~5–25 days (often 1–3 weeks) — notably longer than FMF attacks.
• Progression: Generally non-progressive between attacks in those without amyloidosis; some patients have decreasing attack frequency with age, while a subset develop persistent subclinical inflammation that culminates in AA amyloidosis (the principal progressive, organ-threatening sequela).
• Remission patterns: Individual attacks are self-limited (spontaneous resolution); treatment-induced remission of attacks and normalization of acute-phase reactants is achievable with IL-1 blockade.
• Critical period for intervention: sustained control of inflammation (normalizing SAA/CRP) is the window to prevent amyloidosis; once renal amyloid causes significant proteinuria/CKD, damage is harder to reverse.

9. Inheritance and Population

Epidemiology. - Prevalence: rare; GeneReviews estimates ~1 in 1,000,000 worldwide (likely an underestimate given under-recognition and low-penetrance carriers). TRAPS is the second most common hereditary periodic fever after FMF in many European cohorts. - Incidence: not precisely established (orphan disease).

Genetic transmission: - Inheritance pattern: Autosomal dominant (50% transmission risk per offspring). - Penetrance: High for cysteine-disrupting variants and T50M; markedly reduced for R92Q and P46L. Many R92Q carriers are asymptomatic. - Expressivity: highly variable, even within families carrying the same mutation. - Genetic anticipation: Not a feature (this is not a repeat-expansion disorder). - Germline mosaicism / de novo: de novo mutations occur; mosaicism reported uncommonly. - Founder effects: Original FHF kindred Irish/Scottish; specific variants show population clustering. R92Q and P46L are common population variants rather than founder disease alleles in the classic sense. - Consanguinity: Not relevant (dominant disease). - Carrier "frequency": For low-penetrance alleles, gnomAD shows R92Q ~0.5–1% in some populations and P46L enriched in African-ancestry groups — these are heterozygous susceptibility alleles, not recessive carrier states.

Demographics: Reported across many ethnicities; no strong sex bias (roughly M:F ≈ 1:1, perhaps slight female excess in some series). Geographic distribution of variants varies (P46L more frequent in West African populations). Age distribution skews to childhood onset but spans all ages.

10. Diagnostics

Clinical/laboratory: - Acute-phase reactants during attacks: elevated CRP (HP:0011227), ESR (HP:0003565), serum amyloid A (SAA), neutrophilic leukocytosis, reactive thrombocytosis, anemia of chronic disease; polyclonal hypergammaglobulinemia. Persistently elevated SAA between attacks signals amyloidosis risk. - Soluble TNFR1 (sTNFR1): classically low/inappropriately reduced plasma levels between attacks (McDermott 1999 noted ~half-normal soluble TNFR1) — supportive but not diagnostic; the sTNFR1/sTNFR2 ratio has been explored for differential diagnosis. - LOINC: CRP (e.g., 1988-5), ESR (4537-7), albumin/creatinine ratio for renal amyloid monitoring.

Biomarkers: SAA and CRP for disease activity; proteinuria for amyloid surveillance.

Imaging/biopsy: - Histopathology of muscle/fascia: monocytic fasciitis (panniculitis/fasciitis with mononuclear infiltrate) rather than true myositis — characteristic. - Skin biopsy: superficial/deep perivascular and interstitial mononuclear infiltrate. - Tissue biopsy with Congo red staining (apple-green birefringence) — gold standard to confirm AA amyloidosis (subcutaneous fat, rectal, or renal biopsy); immunohistochemistry confirms SAA-type (AA) amyloid. - SAP scintigraphy (where available) to assess amyloid burden.

Genetic testing (definitive): - Targeted TNFRSF1A sequencing (single-gene) confirms diagnosis when clinical suspicion is high. - Hereditary periodic fever / autoinflammatory NGS gene panels (covering MEFV, MVK, NLRP3, TNFRSF1A, etc.) are standard first-line genetic testing for undifferentiated periodic fever. - WES/WGS reserved for atypical/unsolved cases. - CMA, karyotyping, FISH, mtDNA, and repeat-expansion testing are not applicable (coding missense disease). - Interpretation caveat: finding R92Q or P46L requires cautious interpretation given reduced penetrance — genotype must be integrated with phenotype.

Clinical criteria / classification: The Eurofever/PRINTO classification criteria and the newer 2024 EULAR/ACR (AIDA-informed) provisional classification criteria for autoinflammatory periodic fevers are used; historically the "TRAPS clinical score." Key discriminators: attack duration >1 week, migratory myalgia with rash, periorbital edema, positive family history, dominant inheritance.

Differential diagnosis: FMF (shorter attacks, AR, MEFV, colchicine-responsive), hyper-IgD/mevalonate kinase deficiency (MKD/HIDS) (MVK, early onset, cervical adenitis, elevated IgD), cryopyrin-associated periodic syndromes (CAPS/NLRP3), PFAPA, systemic JIA / adult-onset Still disease, Behçet disease, and infection/malignancy.

Screening: No population newborn screening. Cascade genetic testing of at-risk relatives in known-mutation families is appropriate; prenatal/preimplantation testing is possible for high-penetrance variants but ethically nuanced given variable expressivity.

11. Outcome / Prognosis

• Survival/life expectancy: Generally normal life expectancy if amyloidosis is prevented/controlled. Untreated, AA amyloidosis is the major determinant of mortality, via progressive renal failure.
• Disease-specific mortality: Driven almost entirely by amyloid-related end-organ (renal, and less often hepatic/cardiac/GI) failure.
• Morbidity: Recurrent prolonged painful attacks → chronic pain, fatigue, missed school/work; ocular involvement; complications of chronic steroid use historically.
• AA amyloidosis frequency: Historically reported in ~10–25% of patients overall, higher (up to ~25%+) for cysteine/T50M genotypes and very low for R92Q/P46L. Per GeneReviews, once amyloidosis develops, "proteinuria and kidney failure occur in 80%–90%" of those affected.
• Prognostic factors: Genotype is the strongest predictor — cysteine-disrupting variants and T50M predict severe, persistent disease and amyloid risk; R92Q/P46L predict mild/self-limited disease. Persistently elevated SAA/CRP between attacks predicts amyloidosis. Early effective IL-1 blockade improves outcomes.
• Recovery potential: Attacks fully resolve between episodes; with modern biologics, clinical and biochemical remission is achievable in the majority, and continuous therapy can prevent or stabilize amyloidosis.

12. Treatment

Goals: abort/prevent attacks, normalize acute-phase reactants (CRP/SAA), and prevent AA amyloidosis.

Pharmacotherapy / biologics (mainstay): - IL-1 inhibitors — first-line for persistent disease: - Anakinra (recombinant IL-1 receptor antagonist) — rapid, effective; useful diagnostically and for amyloidosis-complicated disease. - Canakinumab (anti-IL-1β monoclonal antibody) — the only biologic with a pivotal RCT and regulatory approval for TRAPS (FDA/EMA approval for periodic fever syndromes including TRAPS). In the phase 3 CLUSTER trial (De Benedetti et al., NEJM 2018, PMID:29768139; ClinicalTrials.gov NCT02059291), canakinumab controlled and prevented flares in TRAPS, MKD/HIDS, and colchicine-resistant FMF.

> *"Canakinumab was effective... in controlling and preventing flares in patients with colchicine-resistant familial Mediterranean fever, mevalonate kinase deficiency... and TRAPS."* — De Benedetti et al., *NEJM* 2018 (**PMID:29768139**)

• Modality: monoclonal antibody (canakinumab) / recombinant protein (anakinra). Suggested annotation: treatment_term NCIT:C15986 (Pharmacotherapy) + therapeutic_agent (canakinumab/anakinra), therapeutic_modality: MONOCLONAL_ANTIBODY (canakinumab).
• TNF inhibitor — etanercept (soluble TNFR2-Fc fusion): historically used; partially effective but with waning/incomplete responses and poor long-term adherence:

"Etanercept reduces symptoms and serum levels of inflammatory markers of TRAPS in a dose-dependent manner, but does not completely normalize symptoms or acute-phase reactant levels." — Bulua et al., Arthritis Rheum 2012 (PMID:22006113)

• Important pharmacologic caveat: monoclonal anti-TNF antibodies (infliximab, and adalimumab) can paradoxically worsen TRAPS (reported flare induction) and are generally avoided; etanercept (receptor decoy) behaves differently from anti-TNF mAbs here.
• IL-6 blockade (tocilizumab): reported effective in refractory/biologic-experienced cases (off-label).
• Corticosteroids: abort/attenuate acute attacks (high-dose during flares) but chronic steroid use causes toxicity and is not a long-term solution; escalating dose requirements are common.
• NSAIDs: symptomatic relief only.
• Colchicine: largely ineffective in TRAPS (unlike FMF) — an important contrast.

Pharmacogenomics: Response is genotype-correlated at the disease-allele level (severe genotypes need continuous biologics) rather than via drug-metabolism PGx; no validated CPIC-style PGx guidance specific to TRAPS.

Advanced/experimental therapeutics: No approved gene/cell/RNA therapy. Emerging interest in agents targeting ER stress, mtROS, NLRP3 inflammasome, and JAK inhibitors in refractory autoinflammation — investigational only.

Supportive/management of amyloidosis: suppress inflammation to halt amyloid; manage CKD/nephrotic syndrome (ACE inhibitors/ARBs, dialysis); renal transplantation in end-stage renal disease, with continued IL-1 blockade to protect the graft.

Suggested MAXO terms: Pharmacotherapy (NCIT:C15986); supportive care (MAXO:0000950); organ transplantation/renal transplant (MAXO:0010039); genetic counseling (MAXO:0000079); dietary/supportive management as applicable. (Use NCIT/CHEBI therapeutic_agent for canakinumab, anakinra, etanercept, prednisone; note canakinumab/anakinra/etanercept are biologics — likely need NCIT rather than CHEBI agents; corticosteroid CHEBI:50858/prednisone CHEBI:8382; colchicine CHEBI:23359 noted as ineffective.)

13. Prevention

• Primary prevention: Not preventable (genetic). Genetic counseling for affected families is the key primary-prevention tool; prenatal/preimplantation genetic testing is feasible for high-penetrance variants.
• Secondary prevention (early detection): Cascade genetic testing of at-risk relatives; early diagnosis enables early anti-inflammatory therapy.
• Tertiary prevention (complication prevention): the central, achievable goal — continuous suppression of inflammation (normalizing SAA/CRP with IL-1 blockade) to prevent AA amyloidosis, plus monitoring urinalysis/proteinuria and renal function for early amyloid detection.
• Immunization: No vaccine (not infectious). Standard immunizations advised, with awareness that vaccination can occasionally trigger a flare and that live vaccines need consideration on biologics.
• Counseling: genetic counseling regarding autosomal-dominant 50% transmission, variable expressivity, and the special interpretive challenges of R92Q/P46L (MAXO:0000079).
• Public/environmental health: Not applicable.

14. Other Species / Natural Disease

• Taxonomy: Human disease — Homo sapiens (NCBITaxon:9606).
• Orthologous gene: mouse Tnfrsf1a (NCBI Gene 21937); the gene/receptor (TNFR1/p55) is highly conserved across mammals.
• Natural disease in other species: No well-recognized spontaneous TRAPS-equivalent in companion animals or wildlife (OMIA has no established orthologous natural disease). TRAPS is essentially a human germline disorder; animal "disease" is engineered (see §15).
• Comparative biology / conservation: TNF–TNFR1 signaling and the cysteine-rich-domain architecture are deeply evolutionarily conserved, which is why mouse knock-ins recapitulate aspects of the disease.
• Zoonotic potential / transmission: None (non-infectious genetic disease).

15. Model Organisms

• Mouse "knock-in" models: The key model is the TNFR1 knock-in mouse carrying TRAPS-associated mutations (e.g., T50M; C33Y), generated and characterized in the same body of work establishing the misfolding/ER-retention and mtROS mechanisms (Lobito et al. Blood 2006, PMID:16684962; Bulua et al. J Exp Med 2011, PMID:21282379). These mice show ER retention of mutant TNFR1, elevated mitochondrial ROS, and enhanced inflammatory responses to LPS, recapitulating the cellular phenotype.

"...a mouse 'knock-in' model of TRAPS... TRAPS mutant TNFR1 molecules were retained intracellularly and colocalized with endoplasmic reticulum markers." — Lobito et al. 2006 (PMID:16684962)

• Cellular / in vitro models: transfected cell lines expressing mutant TNFR1; patient-derived monocytes/PBMCs and mouse embryonic fibroblasts (MEFs) harboring TRAPS mutations — used to demonstrate elevated baseline mtROS and augmented cytokine output (Bulua 2011, PMID:21282379). iPSC-derived myeloid models are an emerging avenue.
• Model types available: knock-in (point-mutation) mice; transgenic/overexpression cell systems; primary patient cells (ex vivo).
• Phenotype recapitulation: Models faithfully reproduce the molecular phenotype (ER retention, mtROS, hyper-responsive innate cytokine secretion, NF-κB/MAPK activation). They are somewhat less faithful to the full clinical periodic-fever syndrome (the dramatic recurrent multi-organ human attacks and AA amyloidosis are incompletely modeled) — a candidate HUMAN_MODEL_MISMATCH consideration for dismech: molecular mechanism well-modeled, but periodicity/amyloidosis less so.
• Applications: dissecting the misfolding→ER-stress→mtROS→cytokine axis, testing antioxidants/IL-1 blockade, and validating that IL-1β is the key effector.
• Resources: MGI (mouse Tnfrsf1a), IMPC/KOMP for null alleles (note: null alleles model TNF-loss, not the TRAPS gain-type mechanism — use knock-in lines for disease modeling).

Summary of Key Verified Citations (re-validate before YAML commit)

Sources consulted: - McDermott et al., Cell 1999 — PubMed - Aksentijevich et al., Am J Hum Genet 2001 — PMC1235304 - Lobito et al., Blood 2006 — PMC1895878 - Bulua et al., J Exp Med 2011 — PMC3058571 - Bulua et al., Arthritis Rheum 2012 — PubMed - Lachmann et al., Eurofever/EUROTRAPS 2014 — PMC4251160 - De Benedetti et al., CLUSTER trial, NEJM 2018 — PubMed and NCT02059291 - GeneReviews: TNF Receptor-Associated Periodic Fever Syndrome — NBK586171 - Revisiting TRAPS: Current Perspectives, Int J Mol Sci 2020 — MDPI - R92Q age-at-onset cohort, Front Immunol 2017 — PMC5366323 - NORD: TRAPS

Curation flags for dismech: (1) Re-fetch every PMID with just fetch-reference and confirm each snippet is an exact substring before committing — the two ⚠️ PMIDs (Aksentijevich 11443543, Simon ~20133695) need digit re-verification. (2) The R92Q/P46L low-penetrance variants are an ideal place to record a mechanistic_hypotheses/reduced-penetrance nuance. (3) Consider a HUMAN_MODEL_MISMATCH discussion note for the mouse knock-in (molecular mechanism modeled; full periodic-fever/amyloidosis phenotype not). (4) evidence_source tags: McDermott/Aksentijevich/Lachmann/De Benedetti/Bulua-2012 = HUMAN_CLINICAL; Lobito (knock-in mouse + transfected cells) = mix of MODEL_ORGANISM + IN_VITRO (split into separate evidence items); Bulua-2011 mtROS = mix of MODEL_ORGANISM (MEFs/mice) + IN_VITRO (human cells) — split accordingly.