PAPA Syndrome

1. Disease Information

Overview. PAPA syndrome is a rare, autosomal dominant monogenic autoinflammatory disorder caused by heterozygous pathogenic variants in PSTPIP1 (proline-serine-threonine phosphatase-interacting protein 1, also historically named CD2BP1), located at 15q24.3. It is the prototype of a broader "PSTPIP1-associated inflammatory diseases" (PAID) spectrum. It was first delineated clinically by Lindor et al. (1997) as "a new autosomal dominant disorder of pyogenic sterile arthritis, pyoderma gangrenosum, and acne" (ScienceDirect summary), and the causal gene was identified by Wise et al., Human Molecular Genetics 2002 (PMID not directly returned by search but DOI 10.1093/hmg/11.8.961), who found co-segregating CD2BP1/PSTPIP1 mutations (p.E250Q, p.A230T) in two multiplex families and showed by yeast two-hybrid assay that both severely reduce binding to PTP-PEST (Wise et al. 2002).

Key identifiers: - OMIM: 604416 — "Pyogenic Sterile Arthritis, Pyoderma Gangrenosum, and Acne" (OMIM:604416) - Orphanet: ORPHA:69126 (Orphanet) - MONDO: MONDO:0011462 (Wikidata cross-reference) - Gene: PSTPIP1 (HGNC:9581), chr15q24.3, also historically CD2BP1 - Common synonyms: PAPA syndrome; Pyogenic Arthritis-Pyoderma Gangrenosum-Acne syndrome; Familial recurrent arthritis

Evidence basis. Almost all published data derive from aggregated case reports/case series and family pedigrees (individual-patient level, not large-cohort EHR data) — this is one of the rarest monogenic autoinflammatory diseases, with the literature dominated by single-family and small-series reports rather than registries.

2. Etiology

Disease causal factor — genetic, single-gene, autosomal dominant. PAPA syndrome is caused by heterozygous missense variants in PSTPIP1. The two "classic," functionally validated PAPA-causing variants are p.A230T and p.E250Q (originally reported as E250Q; some literature also refers to it as E250K in the context of the related PAMI phenotype — see below), both located in the coiled-coil domain of PSTPIP1 and both shown to abolish binding to the phosphatase PTP-PEST by yeast two-hybrid assay (Wise 2002). Additional variants — p.D246N and p.E257G — are classified as "likely pathogenic" based on absence from population databases, location within the same critical PSTPIP1 domain, and de novo occurrence without family history (Frontiers Genetics case report/review, 2026).

Genetic risk factors. The causal variants themselves are the dominant risk factor; PAPA syndrome shows autosomal dominant inheritance with incomplete penetrance and variable expressivity — even within the same family and the same variant, disease severity and organ involvement vary substantially (PMC3737487, genotype-phenotype study of 5 patients). No environmental cause is established; physical trauma is a recognized trigger of flares (pathergy) rather than a cause.

Gene-environment interaction. The clearest gene-environment interplay is pathergy — minor trauma or injection precipitates sterile abscesses and joint flares in genetically susceptible (PSTPIP1-mutant) individuals, attributed to dysregulated neutrophil recruitment and IL-1β hyperproduction at sites of minor injury.

Protective factors. None are established in the literature; this is expected for an ultra-rare, highly penetrant single-gene autosomal dominant disorder.

3. Phenotypes

Articular

• Sterile pyogenic (destructive) arthritis — HP:0033798 (Sterile pyogenic arthritis) or generically HP:0001369 (Arthritis). Recurrent, migratory, typically monoarticular flares, most often affecting elbows, knees, and ankles; occurs spontaneously or after minor trauma; leads to accumulation of sterile purulent synovial fluid and, if untreated, joint destruction (PMC3737487; imaging review, Pediatric Radiology 2018). Synovial fluid shows exceedingly high (often >100,000/mm³) sterile neutrophilic white cell counts, a key differentiator from true septic arthritis (PubMed 28251506).
• Onset: typically early childhood.
• Course: arthritis tends to subside by/after puberty as cutaneous disease intensifies.

Cutaneous

• Pyoderma gangrenosum (HP:0031928 or general "cutaneous ulceration") — recurrent, non-healing, sterile skin ulcers, often triggered by minor trauma (pathergy). Onset generally later than arthritis — adolescence/early adulthood.
• Severe cystic/nodulocystic acne (HP:0001061 Acne inversa / cystic acne terms) — often severe and scarring, emerging around/after puberty.
• Pathergy — exaggerated inflammatory response and sterile abscess formation at injection or injury sites (a hallmark clinical sign, similar to Behçet disease pathergy).
• Suppurative/pyogenic skin abscesses; in the extended PAID spectrum, hidradenitis suppurativa (see PASH/PAPASH below).

Laboratory abnormalities

• Elevated acute-phase reactants during flares (ESR, CRP).
• Markedly elevated IL-1β and circulating neutrophil granule enzymes compared to controls (PMC3737487).
• In the PAMI end of the spectrum: hyperzincemia, hypercalprotectinemia (very high S100A8/A9 / MRP8-14), cytopenias.

Phenotype pattern: temporal segregation is a defining clinical feature — arthritis dominates in childhood, and cutaneous disease (PG, acne) dominates from puberty onward, though this is variable between and within families (incomplete penetrance/variable expressivity).

Quality of life impact. Disfiguring/scarring skin disease (PG scars, cystic acne scarring) and destructive arthritis both carry substantial psychosocial and functional burden; specific EQ-5D/SF-36 data for PAPA syndrome were not identified in this search and are likely absent given disease rarity — flag as a gap.

4. Genetic/Molecular Information

Causal gene: PSTPIP1 / HGNC:9581, chr15q24.3; OMIM gene entry 606347 (gene), disease entry 604416.

Pathogenic variants (classic/validated): | Variant | Classification | Domain | Functional evidence | |---|---|---|---| | p.A230T | Pathogenic | Coiled-coil | Segregates in families; disrupts PTP-PEST binding, ↑pyrin binding | | p.E250Q | Pathogenic | Coiled-coil | Segregates in families; disrupts PTP-PEST binding, ↑pyrin binding | | p.D246N | Likely pathogenic | Coiled-coil | De novo, absent from population DBs | | p.E257G | Likely pathogenic | Coiled-coil | De novo, absent from population DBs |

A recent systematic review of PAMI-spectrum cases found 41/43 (95%) carried the heterozygous p.E250K variant (PMC10454568, PAMI systematic review, 2023) — note this is a distinct variant from the classic PAPA-causing E250Q, illustrating allelic heterogeneity across the PSTPIP1-associated disease spectrum (genotype–phenotype correlations discussed further under §9).

Variant type/class: All known causal variants are missense, clustered in the coiled-coil domain of PSTPIP1.

Functional consequence — gain-of-function/dominant-negative-type effect at the protein-interaction level: PAPA-associated PSTPIP1 mutants show reduced binding to PTP-PEST, leading to hyperphosphorylation of PSTPIP1 and consequent markedly increased affinity for pyrin (MEFV) (PLOS ONE, PMC2702820; [WebSearch synthesis of PSTPIP1-pyrin mechanism]). This is a molecular gain-of-interaction rather than classic enzymatic gain/loss of function.

Modifier considerations: No formal modifier genes are established, but marked intrafamilial variable expressivity (documented in the same 5-patient genotype-phenotype series) implies unidentified genetic or stochastic modifiers (PMC3737487).

Allele frequency: These variants are private/rare, essentially absent from population databases (gnomAD) consistent with high penetrance dominant disease-causing status; specific allele-frequency figures were not returned by this search pass.

Epigenetics/chromosomal abnormalities: Not applicable — PAPA syndrome is a point-mutation Mendelian disorder; no epigenetic mechanism or copy-number/translocation etiology is described in the literature surveyed.

5. Environmental Information

• Physical trauma / minor injury is the principal recognized environmental trigger, producing the pathergy phenomenon at both joint and skin sites.
• No specific toxin, infectious agent, or occupational exposure is implicated as causal; this is consistent with a fully genetically determined disease.
• No infectious trigger is causal, although the arthritis and skin lesions can be clinically mistaken for infection (hence "pyogenic," "gangrenosum" naming) — a critical differential-diagnosis point rather than a true infectious etiology.

6. Mechanism / Pathophysiology

Causal chain (numbered, from mutation to clinical manifestation):

1. A heterozygous missense variant (e.g., p.A230T, p.E250Q) in the coiled-coil domain of PSTPIP1 leads to markedly reduced binding affinity between PSTPIP1 and the tyrosine phosphatase PTP-PEST (demonstrated by yeast two-hybrid; Wise 2002).
2. Reduced PTP-PEST engagement results in loss of PTP-PEST-mediated dephosphorylation of PSTPIP1, so mutant PSTPIP1 accumulates in a hyperphosphorylated state (PMC2702820).
3. Hyperphosphorylated PSTPIP1 leads to markedly increased binding affinity for pyrin (encoded by MEFV, the familial Mediterranean fever gene) — mechanistically linking PAPA syndrome to the same pyrin-inflammasome pathway as FMF (PNAS, pyrin-PSTPIP1 binding paper; [WebSearch synthesis]).
4. Enhanced pyrin–PSTPIP1 binding results in pyrin being recruited (via PSTPIP1) into ASC specks with unusually high efficiency — i.e., PAPA-mutant PSTPIP1 promotes assembly of the pyrin inflammasome (PMC2702820).
5. Pyrin inflammasome assembly activates caspase-1, which cleaves pro-IL-1β and pro-IL-18 into their active, secreted forms ([WebSearch synthesis, pyrin-inflammasome-caspase-1-IL-1β cascade]).
6. IL-1β/IL-18 overproduction, together with dysregulated neutrophil chemotaxis (PSTPIP1's independent cytoskeletal role — see step 7), drives local and systemic sterile neutrophilic inflammation.
7. Branch — cytoskeletal/adaptor arm (parallel, upstream-independent of inflammasome): wild-type PSTPIP1 is an F-BAR–domain cytoskeleton-associated adaptor that (a) in T cells, bridges CD2 to WASP (Wiskott-Aldrich syndrome protein), coupling TCR engagement to actin polymerization required for immunological synapse formation (PubMed 12530983); and (b) in neutrophils/macrophages, localizes to the trailing uropod edge with PIP5K1C/DNM2 to regulate migration, and controls extracellular-matrix degradation and filopodia formation via podosome regulation (Blood, ASH publications). PAPA-mutant PSTPIP1 perturbs this cytoskeletal-regulatory function, contributing to exaggerated neutrophil influx at sites of minor trauma — the cellular basis of pathergy.
8. Excess IL-1β/IL-18 signaling plus exaggerated, trauma-triggered neutrophil infiltration culminate in the clinical triad: sterile pyogenic (neutrophil-rich) destructive arthritis, pyoderma gangrenosum ulceration, and severe cystic acne — with a temporal pattern in which arthritis predominates in childhood (when trauma/joint use is high) and cutaneous disease predominates from puberty onward (hormonally influenced acne, ongoing pathergy-driven ulceration).

Inferential note: the step linking hyperphosphorylation directly to increased pyrin binding (step 3) and the step linking cytoskeletal dysregulation quantitatively to pathergy severity (step 7→8) are supported mainly by in vitro biochemical and cell-biology studies; direct demonstration that this cascade alone (absent the cytoskeletal arm) is sufficient to produce the full clinical triad in vivo is not established — the mouse model data (below) show a dissociation between systemic cytokine elevation and clinical skin/joint phenotype, indicating the causal chain from IL-1β elevation to organ-specific lesion formation is incompletely modeled.

Molecular pathways: pyrin (MEFV) inflammasome pathway; IL-1β/IL-18 (caspase-1) signaling; CD2–WASP–actin cytoskeletal signaling (immunological synapse formation); F-BAR-domain membrane remodeling/podosome regulation.

Cell types involved (candidate CL terms): - Neutrophils (CL:0000775) — pathergy, sterile arthritis/PG neutrophilic infiltrate - Macrophages (CL:0000235) — cytoskeletal/podosome dysfunction, IL-1β production - T lymphocytes (CL:0000084) — CD2/WASP synapse dysfunction - Synoviocytes/synovial fibroblasts — site of joint inflammation

Suggested GO terms: - GO:0043123 — positive regulation of canonical NF-kappaB signal transduction (downstream inflammatory signaling) - GO:0002534 — cytokine production involved in inflammatory response - GO:0097169 — AIM2 inflammasome complex assembly (analogous; pyrin inflammasome-specific GO term GO:0072559 "NLRP1 inflammasome complex" is not exact — best available may be the general "inflammasome complex" GO:0061702) - GO:0030041 — actin filament polymerization - GO:0002376 — immune system process (broad, for CD2/WASP synapse formation)

7. Anatomical Structures Affected

• Organ level (primary): joints (elbows, knees, ankles predominant), skin (site of PG ulcers and acne).
• Secondary: in the PAMI/PSTPIP1-spectrum extreme, reticuloendothelial system — hepatosplenomegaly, lymphadenopathy, bone marrow (cytopenias).
• Body systems: musculoskeletal, integumentary, immune (innate).
• Tissue/cell level: synovium (neutrophilic synovitis), dermis/epidermis (ulcerative pyoderma gangrenosum, pilosebaceous unit in acne).
• Subcellular: cytoskeleton/cell cortex (F-BAR domain membrane deformation, filopodia/podosome structures), cytoplasmic inflammasome (ASC speck) assembly.
• Candidate UBERON terms: UBERON:0000982 (synovial joint), UBERON:0002097 (skin of body), UBERON:0001004 (respiratory system - N/A here), UBERON:0002370 (thymus - N/A). Most relevant: UBERON:0000982 (joint), UBERON:0002097 (skin).
• Laterality: typically unilateral/asymmetric during individual arthritis flares (migratory monoarticular pattern), though different joints affected over time.

8. Temporal Development

• Onset: childhood, classically before age 10, sometimes as early as infancy for arthritis; cutaneous manifestations (PG, cystic acne) typically emerge later, around puberty/adolescence.
• Pattern: episodic/relapsing-remitting for both arthritis and PG flares, often trauma-triggered (pathergy).
• Progression: arthritis is most active in childhood/pre-puberty and tends to attenuate afterward; cutaneous disease (PG and severe acne) increases from puberty into adulthood — a documented "phenotypic switch" over the disease course (PMC3737487).
• Duration: chronic, lifelong (though joint disease activity often diminishes with age; residual joint damage from earlier destructive flares may persist).
• Critical periods: childhood/adolescence — periods of highest inflammatory activity, when early diagnosis and IL-1 blockade could in principle limit joint destruction and cutaneous scarring; this is inferred rather than demonstrated by controlled trial data given disease rarity.

9. Inheritance and Population

• Epidemiology: exceptionally rare; prevalence <1 per 1,000,000. As of the WebSearch source cited, only ~34 patients from 5 kindreds (2 US, 1 Italian, 1 Dutch, 1 New Zealand) had been formally reported in the classic literature (WebSearch summary; see also Orphanet); subsequent case reports (including a 2026 Chinese family report) have added further cases but the total remains in the low hundreds worldwide across the full PSTPIP1-spectrum literature.
• Inheritance pattern: autosomal dominant.
• Penetrance: incomplete.
• Expressivity: markedly variable, both between and within families (documented directly in the 5-patient genotype-phenotype study, PMC3737487).
• Genetic anticipation: not reported/expected (not a repeat-expansion disorder).
• Founder effects/consanguinity: not specifically reported for the classic PAPA-causing variants; several kindreds independently ascertained across different populations/geographies.
• Genotype–phenotype spectrum note: the E250K (as opposed to classic E250Q) and E257K variants are specifically associated with the more severe PAMI phenotype (myeloid-related proteinemia, hyperzincemia/hypercalprotectinemia, cytopenias, failure to thrive) rather than classic PAPA — an important within-gene genotype-phenotype correlation to track separately in curation (PMC10454568; Sciencedirect phenotype-genotype paper/PubMed 33218716).
• Sex ratio / geographic distribution: no strong sex predilection or endemic geographic clustering reported in the sources surveyed.

10. Diagnostics

Clinical/laboratory: - Synovial fluid analysis: exceedingly high, sterile neutrophilic cell counts (differentiates from true septic arthritis) — a key diagnostic discriminator emphasized in a dedicated case series (PubMed 28251506). - Elevated ESR/CRP during flares; elevated IL-1β; in PAMI-spectrum disease, markedly elevated serum zinc and calprotectin (S100A8/A9). - Imaging (radiographs, MRI, ultrasound) used to characterize joint destruction and differentiate from infectious/other inflammatory arthritis — reviewed specifically for PAPA in a Pediatric Radiology imaging-findings paper (Springer 2018). - Skin biopsy of PG lesions: neutrophilic dermatosis pattern (nonspecific but supportive).

Genetic testing: Single-gene sequencing of PSTPIP1 (Sanger or targeted NGS) is the diagnostic standard given the small number of known causal variants clustering in the coiled-coil domain; autoinflammatory-disease gene panels including PSTPIP1, MEFV, NLRP3, TNFRSF1A, MVK, etc. are commonly used given phenotypic overlap with other periodic fever/autoinflammatory syndromes.

Clinical criteria / differential diagnosis: No formal consensus diagnostic criteria akin to DSM/ICD were identified in this search; diagnosis remains clinical, supported by genetic confirmation. Key differentials: - Septic arthritis (ruled out by sterile cultures despite very high synovial WBC). - Pyoderma gangrenosum from other causes (IBD-associated, idiopathic). - PASH syndrome (Pyoderma gangrenosum, Acne, Suppurative Hidradenitis) — lacks the sterile pyogenic arthritis of PAPA; caused variably by PSTPIP1 variants or other/no identified gene (PubMed 21745697). - PAPASH (PAPA + hidradenitis suppurativa). - PsAPASH (PASH + psoriatic arthritis). - PASS syndrome (PG, acne, ankylosing spondylitis ± hidradenitis suppurativa). - PAC syndrome (PG, acne, ulcerative colitis). - PAMI syndrome (PSTPIP1-associated myeloid-related proteinemia inflammatory syndrome) — a more severe, often earlier-onset phenotype associated specifically with E250K/E257K, featuring failure to thrive, lymphadenopathy, splenomegaly, and cytopenias in addition to/preceding classic PAPA features. (Spectrum summarized in WebSearch synthesis of differential-diagnosis sources, including DermNet NZ.)

11. Outcome/Prognosis

• No formal survival/mortality statistics are established — PAPA syndrome is not typically fatal, but morbidity from joint destruction and disfiguring cutaneous scarring can be substantial if untreated.
• Morbidity: destructive arthropathy (if arthritis flares are inadequately controlled in childhood), disfiguring PG scarring, severe acne scarring.
• Complications: secondary infection of ulcerated PG lesions; in PAMI-spectrum disease, cytopenias and growth failure add additional morbidity.
• Prognostic factors: early recognition and IL-1 pathway blockade may limit long-term joint damage and scarring, though this is inferred from case-series treatment response data rather than controlled prognostic studies (disease too rare for such studies to exist).

12. Treatment

Pharmacotherapy — biologics targeting IL-1 and TNF pathways are the mainstay:

• Anti-IL-1 agents (anakinra, canakinumab): most effective for the arthritis component; markedly lower efficacy against PG and acne according to a 2025 systematic review of 10 case-report studies (19 patients total) (Springer Nature, Archives of Dermatological Research 2025). Canakinumab (dosed every 4-8 weeks) shows better compliance and fewer injection-site reactions than daily anakinra, though head-to-head comparative data remain limited; both are used, but the review explicitly calls for RCTs given the current evidence base is limited to small case series.
• Anti-TNF agents (etanercept, adalimumab, infliximab, golimumab): also reported effective, with some evidence that infliximab or high-dose golimumab may outperform etanercept/adalimumab for severe PG lesions specifically (WebSearch synthesis; foundational case report: PubMed 15580218, abnormal TNF-α production and etanercept efficacy; Use of TNF inhibitors in PAPA syndrome, PMC4599379).
• Combination anti-TNF + anti-IL-1 therapy: used for cases refractory to monotherapy with either class, reported as more effective than escalating corticosteroids (WebSearch synthesis of combination-therapy case reports).
• Corticosteroids (systemic and intralesional/intra-articular): used historically and still commonly as adjunct/bridge therapy, though associated with significant toxicity with prolonged use.

Suggested NCIT terms: - NCIT:C15986 (Pharmacotherapy) — generic action - Anakinra: therapeutic_agent candidate (NCIT has an "Anakinra" concept; verify exact CURIE via OAK before curation — not independently confirmed in this search pass) - Canakinumab, Infliximab, Etanercept, Adalimumab — likewise verify exact NCIT CURIEs at curation time - NCIT:C2874 (Corticosteroid) class-level term as an alternative/adjunct

Surgical/supportive: avoidance of unnecessary surgical intervention/injections given pathergy risk; wound care for PG ulcers; dermatologic management of acne (isotretinoin reported in some case series, though can be associated with flares in some autoinflammatory-adjacent conditions — verify per-case before curating as a general recommendation).

Experimental/emerging: No PAPA-syndrome-specific registered clinical trials (NCT) were identified in this search pass; given the disease's rarity, most treatment evidence is derived from off-label biologic use documented in case reports/series rather than formal trials — this should be flagged as an evidence gap when curating clinical_trials.

13. Prevention

• No primary prevention exists for this monogenic dominant disorder beyond genetic counseling for at-risk family members (each child of an affected parent has ~50% inheritance risk, subject to incomplete penetrance).
• Secondary/tertiary prevention: the central actionable preventive strategy documented in the literature is avoidance of unnecessary trauma/injections to minimize pathergy-triggered flares, plus early initiation of IL-1/TNF-targeted therapy to prevent cumulative joint destruction and cutaneous scarring.
• Genetic counseling: appropriate given autosomal dominant inheritance with variable expressivity; prenatal/preimplantation testing is technically feasible via single-gene PSTPIP1 testing but is not routinely reported as clinical practice for this non-lethal, treatable disorder.

14. Other Species / Natural Disease

• No naturally occurring veterinary/companion-animal PAPA-syndrome-equivalent disease was identified in this search (searches for OMIA-style veterinary correlates did not surface a distinct entry); this should be recorded as absent/not identified rather than assumed absent.
• Comparative biology is instead addressed through engineered mouse models (below) rather than naturally occurring animal disease.

15. Model Organisms

Genetic mouse model — A230T knock-in/ectopic expression: - Mice ectopically/ubiquitously expressing human PAPA-associated PSTPIP1 A230T were not born at expected Mendelian ratios, and surviving mice showed growth retardation and elevated circulating proinflammatory cytokines (PMC3576065). - Critically, despite elevated circulating cytokines "implicated in active pyoderma gangrenosum," these mice failed to develop the specific skin inflammation and arthritis phenotype seen in human PAPA syndrome (PMC3576065) — this is a HUMAN_MODEL_MISMATCH-type finding per this repository's convention: systemic cytokine dysregulation is recapitulated, but organ-specific lesion formation (joint/skin) is not, suggesting the mouse model captures the inflammasome/cytokine arm of pathogenesis but misses species-specific or context-dependent factors required for the human tissue phenotype (see mechanism §6, step 7-8 caveat). - In vitro cellular studies (non-animal) additionally show that PAPA-mutant A230T increases IL-1β secretion relative to wild-type PSTPIP1 in cell-based assays, consistent with — but independently supporting — the mouse cytokine findings ([WebSearch synthesis of PMC3576065 discussion]).

Related model systems (mechanistic, not disease-specific): - PSTPIP2 (a paralog) knockout/mutant mice (e.g., the classic "cmo" chronic multifocal osteomyelitis mouse) are widely used to study PSTPIP-family adaptor biology in neutrophil-mediated autoinflammation, though PSTPIP2 is genetically and phenotypically distinct from PSTPIP1/PAPA and should not be conflated with a PAPA model per se (PMC9807597). - A separate murine model of pyoderma gangrenosum (not PSTPIP1-based) implicating IL-1β-primed neutrophils and skin-gut crosstalk exists in the literature and may be useful as a mechanistic (not genetic) comparator for the PG component of the PAPA phenotype (Frontiers Immunology 2023).

Model limitations: the existing A230T mouse model recapitulates the biochemical/cytokine axis of disease but not the defining clinical lesions (arthritis, PG), representing a significant translational gap between the demonstrated pyrin-inflammasome/IL-1β mechanism and the tissue-specific human phenotype — an important caveat for any mechanistic module curation that cites this model as supporting evidence for the joint/skin nodes specifically (as opposed to the cytokine-production node).

Summary of Key Ontology Term Candidates for Curation

Note on evidence gaps to flag during curation: (1) no RCT-level treatment data exist — all treatment evidence is case-report/series level; (2) the mouse model shows a human-model mismatch for the tissue-specific (joint/skin) phenotype despite recapitulating the cytokine phenotype; (3) QoL-instrument data (EQ-5D/SF-36) specific to PAPA syndrome were not located in this search pass and may not exist in the primary literature; (4) exact PMIDs for several foundational papers (Wise 2002, Shoham/PNAS pyrin-PSTPIP1 paper, Lindor 1997) should be independently verified and fetched via just fetch-reference before use as KB evidence, since this report's citations came from web search summaries rather than direct PMID lookup for every source.

Sources: - PSTPIP1-Associated Myeloid-Related Proteinemia Inflammatory (PAMI) Syndrome: A Systematic Review - PMC - A de novo heterozygous PSTPIP1 variant associated with PAPA syndrome: Chinese case report and review - Frontiers Genetics - PAPA Syndrome - ScienceDirect Topics overview - A novel pathogenic variant in PSTPIP1 highlights the diversity of PSTPIP1-associated disorders - Rheumatology/Oxford Academic - Phenotypic Associations of PSTPIP1 Sequence Variants - PubMed 33218716 - PAPA syndrome - Wikidata (OMIM/Orphanet/MONDO IDs) - Orphanet: PAPA syndrome (ORPHA:69126) - Pyrin Modulates the Intracellular Distribution of PSTPIP1 - PMC2702820 - Inflammation in Mice Ectopically Expressing PSTPIP1 A230T - PMC3576065 - Pyrin binds the PSTPIP1/CD2BP1 protein - PNAS - The role of anti-IL-1 drugs in the treatment of PAPA syndrome: a systematic review - Arch Dermatol Res 2025 - Anakinra in PAPASH Spectrum Disorder: Case Report - PMC11244945 - OMIM 604416 - PYOGENIC STERILE ARTHRITIS, PYODERMA GANGRENOSUM, AND ACNE - Genotype, Phenotype, and Clinical Course in Five Patients With PAPA Syndrome - PMC3737487 - Pyogenic arthritis, pyoderma gangrenosum, and acne syndrome in a Chinese family - PMC8362586 - Imaging findings of PAPA syndrome: differential diagnosis - Pediatric Radiology 2018 - PAPA syndrome: differential diagnosis by synovial cell counts - PubMed 28251506 - Pyoderma gangrenosum, acne, and suppurative hidradenitis (PASH) - PubMed 21745697 - PAPA syndrome - DermNet NZ - Mutations in CD2BP1 disrupt binding to PTP PEST and are responsible for PAPA syndrome - Human Molecular Genetics (Wise et al. 2002) - Clinical, Molecular, and Genetic Characteristics of PAPA Syndrome: A Review - PMC3048314 - Abnormal TNF-α production and etanercept efficacy in PAPA syndrome - PubMed 15580218 - Use of TNF inhibitors in the treatment of PAPA syndrome - PMC4599379 - Combination TNF and IL-1 blockade in PAPA syndrome - PMC3952270 - WASp acts downstream of CD2 and CD2AP/PSTPIP1 adaptors - PubMed 12530983 - The F-BAR protein PSTPIP1 controls ECM degradation and filopodia formation in macrophages - Blood/ASH - Molecular interactions of adaptor protein PSTPIP2 in neutrophil-mediated autoinflammation - PMC9807597 - A novel murine model of pyoderma gangrenosum - Frontiers Immunology 2023