OTULIN-Related Autoinflammatory Syndrome

1. Disease Information

Overview. OTULIN-Related Autoinflammatory Syndrome (ORAS), also called otulipenia or autoinflammation, panniculitis, and dermatosis syndrome, autosomal recessive (AIPDS), is a monogenic systemic autoinflammatory disease. The classical recessive form presents in the neonatal period or early infancy with recurrent fever, neutrophilic dermatitis/panniculitis, lipodystrophy, diarrhea, arthritis/arthralgia, and failure to thrive, driven by dysregulated NF-κB signalling and excess M1(linear)-linked polyubiquitin. It was described essentially simultaneously in 2016 by two groups.

• Zhou et al. (PNAS 2016, PMID:27559085): "Biallelic hypomorphic mutations in a linear deubiquitinase define otulipenia, an early-onset autoinflammatory disease." Abstract: "Patients presented with neonatal-onset fever, neutrophilic dermatitis/panniculitis, and failure to thrive" (abstract-derived).
• Damgaard et al. (Cell 2016, PMID:27523608): "A homozygous hypomorphic mutation in human OTULIN causes a potentially fatal autoinflammatory condition" termed OTULIN-related autoinflammatory syndrome (ORAS) (full-text-derived).

Synonyms / alternative names: otulipenia; ORAS; OTULIN deficiency; AIPDS / AIPDSB; "autoinflammation, panniculitis, and dermatosis syndrome, autosomal recessive"; "Infantile-onset periodic fever–panniculitis–dermatosis syndrome" (Orphanet preferred label). The condition belongs to the "relopathies" / "ubiquitin-related autoinflammatory diseases" group (Steiner, Curr Rheumatol Rep 2018, PMID:29846841; Aksentijevich & Zhou, Front Immunol 2017, PMID:28469620).

Information source. Aggregated from disease-level resources (OMIM, Orphanet, ClinGen) and from individual patient case reports/series (PMID:27559085, 27523608, 30804083, 30796585, 35170849, 38914362, 40734169, 41293556). This is a rare disease documented through small case series, not EHR-scale cohorts.

2. Etiology

Primary cause — genetic. ORAS is a monogenic disease caused by variants in OTULIN. Two genetic/inheritance architectures are now recognised:

1. Recessive loss-of-function (classical otulipenia/ORAS): biallelic hypomorphic or amorphic variants → reduced OTULIN catalytic activity/stability → accumulation of M1-linked polyubiquitin and spontaneous NF-κB activation. "an autoinflammatory disease caused by loss-of-function mutations in OTULIN (FAM105B)" (PMID:27559085, abstract).

2. Dominant OTULIN haploinsufficiency: heterozygous deleterious variants (or 5p chromosomal loss) causing a different, infection/trauma-triggered necrosis syndrome (Spaan et al., Science 2022, PMID:35587511).

3. Dominant-negative heterozygous ORAS: rare heterozygous variants (e.g. p.Cys129Ser, p.Arg306Gln) that poison the pathway and produce a spontaneous-inflammation ORAS phenotype despite one normal allele (Davidson, PMID:38630025; Takeda, PMID:38652464).

Genetic risk factors. The disease-causing variant is the cause; consanguinity is a major risk factor for the recessive form (multiple consanguineous Arab, Turkish, Pakistani, Iranian, Moroccan families — PMID:27559085, 40734169, 38914362). No separate susceptibility loci or modifier genes are established, though background LUBAC-pathway genes (RNF31/HOIP [hgnc:16031], RBCK1/HOIL-1, SHARPIN [hgnc:25321]) are mechanistically related.

Environmental risk / trigger factors. Central to the haploinsufficiency form: "episodes of life-threatening necrosis, typically triggered by S. aureus infection" (PMID:35587511, abstract). Broader triggers were later reported: "previously underappreciated triggers, including mechanical or iatrogenic traumas" and "pseudomonal or clostridial infections" (van der Linden, J Hum Immun 2025, PMID:41293556, abstract). Surgery/wound healing is a documented trigger (Nguyen, ACR Open Rheumatol 2025, PMID:40084498, post-operative necrosis). Staels (Front Immunol 2024, PMID:38827742): "OTULIN haploinsufficiency predisposes to environmentally directed inflammation."

Protective factors. For the α-toxin/staphylococcal haploinsufficiency phenotype, naturally acquired anti-α-toxin antibodies are protective and explain incomplete penetrance: "Naturally elicited antibodies against α-toxin contribute to incomplete clinical penetrance" (PMID:35587511, abstract). No dietary/lifestyle protective factors are established.

Gene–environment interaction. The haploinsufficiency phenotype is the clearest G×E example in the group: a germline heterozygous OTULIN defect is clinically silent until an environmental insult (S. aureus α-toxin, trauma, surgery) precipitates tissue necrosis, and anti-toxin humoral immunity modifies penetrance.

3. Phenotypes

Frequencies below are pooled from a 13-patient table (3 new + 10 literature) in AlSaleem et al. (Pediatr Rheumatol 2025, PMID:40734169, full-text, Table 2) for the recessive form, supplemented by the founding series. Interpret pooled percentages cautiously — total documented classical cases number only in the low dozens.

Classical recessive ORAS (neonatal/infantile autoinflammation)

Quotes: "Patients presented with neonatal-onset fever, neutrophilic dermatitis/panniculitis, and failure to thrive" (PMID:27559085); "fever, panniculitis, diarrhea, and arthritis" (Zinngrebe, PMID:35170849). Liver: "OTULIN deficiency caused spontaneous and progressive steatotic liver disease at 10-13 months of age" (Damgaard, Cell Death Differ 2020, PMID:32231246).

Atypical / late-onset recessive: Zinngrebe (PMID:35170849) reported a 7-year-old with "a life-threatening autoinflammatory episode with sterile abscess formation" (compound-het p.M86I/p.W167S) and proposed splitting ORAS into classical and atypical (fulminant late-onset) forms. AlSaleem's 3 Arab patients (p.Val185Phe) also had non-neonatal onset (12 mo, 24 mo, 4 y): "none of our patients had an early or neonatal onset."

OTULIN haploinsufficiency (distinct phenotype)

"Patients suffer from episodes of life-threatening necrosis, typically triggered by S. aureus infection" (PMID:35587511). "six unrelated patients who carry rare, predicted deleterious variants" with skin/lung necrosis (PMID:41293556).

Isolated pyoderma gangrenosum (newest allelic presentation)

Swaminathan et al. (Nat Immunol 2026, PMID:42297973): three patients from two kindreds with homozygous p.R57C, an isolated PG phenotype. "OTULIN-R57C is catalytically active but is unable to bind the linear ubiquitin assembly complex"; "Patient monocytes show heightened expression of IL1B" (abstract). HPO: HP:0025452 Pyoderma gangrenosum.

Quality-of-life impact. Not formally quantified with EQ-5D/SF-36 in the literature. Qualitatively severe: classical cases require chronic biologic therapy, cause growth failure and lipodystrophy; untreated disease is potentially fatal; haploinsufficiency carries risk of life-threatening necrotic episodes.

4. Genetic / Molecular Information

Causal gene. OTULIN (HGNC:25118, 5p15.2). Encodes a 352-aa OTU-family deubiquitinase that is exquisitely specific for Met1 (linear/M1) polyubiquitin (Keusekotten, Cell 2013, PMID:23746843: "specifically hydrolyzing Met1-linked polyubiquitin"). GO suggestions: GO:0101005 deubiquitinase activity; GO:0004843 cysteine-type deubiquitinase activity; GO:0016579 protein deubiquitination (with M1/linear specificity noted in preferred_term); GO:0097039 protein linear polyubiquitination (the substrate it reverses).

Pathogenic variants — recessive ORAS (biallelic)

Variant classes: predominantly missense hypomorphs, one frameshift, one splice-site. Functional consequence = loss of function / hypomorph: p.L272P is "less stable and 1,000–10,000 times less active against M1-linked di- and tetraubiquitin" (PMID:27523608, full text); mutant OTULIN "had decreased enzyme activity relative to cells transfected with WT OTULIN" (PMID:27559085). All founding variants were absent from ExAC and ethnically matched controls.

Variants — dominant OTULIN haploinsufficiency

Spaan (PMID:35587511): six heterozygous variants in 7 patients / 6 kindreds — p.Asp246Val, p.Glu95X (nonsense), p.Asp268TfsX5 (frameshift), p.Asn341Asp, p.Pro254Ser, p.Arg263Gln. Alleles were hypomorphic/amorphic (<25% WT NF-κB inhibition); cumulative population frequency of such alleles ≈ 6×10⁻⁵; constraint metrics LoFtool 0.115, CoNeS −0.78 (intolerant to haploinsufficiency). The disorder is phenocopied by the 5p−/Cri-du-Chat deletion when it removes one OTULIN copy. Additional haploinsufficiency variant: p.Arg263Trp (post-surgical necrosis; PMID:40084498).

Dominant-negative heterozygous ORAS

• p.Cys129Ser — abolishes DUB activity without destabilising protein; "the first dominant-negative mutation linked to ORAS"; "Altered ubiquitination of LUBAC inhibits its recruitment to the TNF receptor signaling complex" (Davidson, J Exp Med 2024, PMID:38630025).
• p.Arg306Gln (de novo) + p.Pro152Leu — "the de novo p.R306Q variant exhibits attenuated deubiquitination activity" and acts dominant-negatively (Takeda, J Exp Med 2024, PMID:38652464).
• p.R57C — catalytically intact but LUBAC-binding-deficient (PUB-interacting motif); isolated PG (PMID:42297973).

Modifier genes / epigenetics / chromosomal. No modifier genes established. The main chromosomal abnormality relevant is the 5p terminal deletion (Cri-du-Chat) acting as a haploinsufficiency phenocopy (PMID:35587511). No disease-specific epigenetic mechanism reported.

5. Environmental Information

• Infectious triggers: Staphylococcus aureus (α-toxin) is the paradigmatic trigger of haploinsufficiency necrosis (NCBITaxon:1280); also Pseudomonas and Clostridium species (PMID:41293556). A tubercular cutaneous abscess has been reported in a haploinsufficient infant (Ks, Indian J Pediatr 2025, PMID:40711650).
• Physical/iatrogenic: mechanical trauma and surgery/wound healing precipitate necrotic episodes (PMID:41293556; PMID:40084498 "Failure to Close").
• Lifestyle factors: none established.
• For classical recessive ORAS, inflammation is largely spontaneous/constitutive rather than environmentally triggered, though LPS amplifies cytokine output ex vivo.

6. Mechanism / Pathophysiology

Causal chain (recessive loss-of-function ORAS)

1. Biallelic hypomorphic OTULIN variant → reduced OTULIN catalytic activity/stability (leads to) failure to hydrolyse Met1-linked polyubiquitin. (Demonstrated: PMID:27523608, 27559085.)
2. Loss of M1-chain editing → accumulation of M1-linked polyubiquitin, especially on/around LUBAC (HOIP/HOIL-1/SHARPIN) signalling complexes. "accumulation of M1-linked polyubiquitin and spontaneous NF-κB activation in myeloid cells" (PMID:27523608). (Demonstrated.)
3. Spontaneous, ligand-independent activation of canonical NF-κB in myeloid cells (monocytes/macrophages) → constitutive transcription of proinflammatory cytokines. (results in) (Demonstrated in patient monocytes and mouse BMDMs.)
4. Overproduction of TNF, IL-1β, IL-6, IL-12/IL-18, IFN-γ → systemic autoinflammation (fever, panniculitis, FTT). "higher IL-1β, IL-6, IL-12, IL-18, and IFN-γ" (PMID:27559085, full text). (Demonstrated.)
5. Branch A — cell-type-specific LUBAC degradation: in B and T cells, OTULIN loss paradoxically causes "downregulation of M1-polyubiquitin signaling by degradation of LUBAC" (HOIP and SHARPIN reduced, proteasome-dependent) (PMID:27523608; Damgaard EMBO Mol Med 2019, PMID:30804083: "loss of OTULIN in patient-derived fibroblasts leads to a reduction in LUBAC levels"). (Demonstrated.)
6. Branch B — sensitisation to TNF-induced cell death: "both patient-derived fibroblasts and OTULIN-deficient monocytes are sensitised to certain types of TNF-induced death"; "apoptotic cells are evident in ORAS patient skin lesions" (PMID:30804083). Cell death (apoptosis/necroptosis) further amplifies inflammation. (Demonstrated.)
7. Branch C — hepatic: hepatocyte OTULIN loss → aberrant mTOR activation and FADD/RIPK1-kinase-dependent hepatocyte apoptosis → steatosis→steatohepatitis→fibrosis→HCC (mouse + 1 patient). "steatohepatitis in OTULIN-deficient livers is associated with aberrant mTOR activation" and "inhibition of mTOR by rapamycin...significantly reduces the liver pathology" (PMID:32231246); "OTULIN Prevents Liver Inflammation and Hepatocellular Carcinoma by Inhibiting FADD- and RIPK1 Kinase-Mediated Hepatocyte Apoptosis" (Verboom, Cell Rep 2020, PMID:32075762). (Model-organism + case.)
8. Clinical manifestation: recurrent fever, neutrophilic dermatosis/panniculitis, lipodystrophy, arthritis, diarrhea, FTT.

Note the cell-type paradox (key mechanistic insight): OTULIN loss is not uniformly pro- or anti-inflammatory — it increases M1-Ub/NF-κB in myeloid cells but degrades LUBAC in lymphocytes. "OTULIN deficiency in ORAS causes cell type-specific LUBAC degradation, dysregulated TNF signalling and cell death" (PMID:30804083).

Causal chain (dominant haploinsufficiency necrosis)

1. Heterozygous OTULIN LOF (50% dosage) → "accumulation of linear ubiquitin in dermal fibroblasts" (CL:0002551 fibroblast of dermis) (PMID:35587511).
2. → OTULIN-dependent accumulation of caveolin-1 (CAV1, hgnc:1527) high-MW K63-ubiquitinated complexes at the fibroblast surface.
3. → caveolin-1 facilitates α-toxin binding and ADAM10 (hgnc:188) retention at the surface → heightened susceptibility to S. aureus α-toxin cytotoxicity. "facilitates the cytotoxic damage inflicted by the staphylococcal virulence factor α-toxin" (PMID:35587511).
4. → trauma/infection trigger → tissue necrosis of skin and lungs; modified by anti-α-toxin antibody titres (penetrance ≈30%).

This is a non-hematopoietic (stromal) mechanism in humans — PBMCs and NF-κB signalling in blood cells were largely normal — contrasting with the hematopoietic-driven inflammation of mouse models (PMID:38827742).

Mechanistic modules / pathways (for KB linking)

• Molecular pathways: canonical NF-κB (GO:0007249; dysregulated positive GO:0043123), TNF-mediated signalling (GO:0033209), mTOR/TORC1 (GO:0038202, GO:0032006), NLRP3 inflammasome assembly (GO:0044546), Wnt/angiogenesis (developmental gumby role, GO:0001525, GO:0016055; PMID:23708998).
• Cellular processes: inflammatory response (GO:0006954), extrinsic apoptosis (GO:0097191), necroptosis (GO:0070266 / GO:0097300), TNF/IL-1β/IL-6 production (GO:0032640/0032611/0032635), neutrophil chemotaxis (GO:0030593). Doglio (Sci Immunol 2023, PMID:38000038): myeloid OTULIN loss "couples RIPK3-dependent cell death to Nlrp3 inflammasome activation and IL-1β secretion."
• Protein dysfunction: loss of OTU-domain M1-Ub hydrolase function; LUBAC (GO:0071797 LUBAC complex) dysregulation (OTULIN normally restrains LUBAC autoubiquitination — Heger, Nature 2018, PMID:29950720; Lyu, Mol Cell 2026, PMID:42880249).
• Cell types (CL): monocyte CL:0000576 / classical monocyte CL:0000860; macrophage CL:0000235; neutrophil CL:0000775; dermal fibroblast CL:0002551; keratinocyte CL:0000312 (Schünke, Nat Commun 2021, PMID:34625557 — RIPK1-mediated keratinocyte necroptosis); hepatocyte CL:0000182; B cell CL:0000236; T cell CL:0000084.

7. Anatomical Structures Affected

• Primary: skin (UBERON:0002097 skin of body; UBERON:0002067 dermis), subcutaneous adipose tissue / panniculus (UBERON:0002190, UBERON:0002072 hypodermis), joints, gastrointestinal tract (UBERON:0000160 intestine).
• Secondary / systemic: liver (UBERON:0002107) — steatosis→HCC; lung (UBERON:0002048) — necrosis/abscess (haploinsufficiency); spleen (UBERON:0002106) — abscesses/splenomegaly; blood/bone marrow (UBERON:0000178 / UBERON:0002371) — leukocytosis, thrombocytosis.
• Body systems: integumentary, musculoskeletal, digestive, hematologic/immune, hepatic, respiratory.
• Subcellular: cytoplasmic ubiquitin–proteasome/signalling machinery; plasma-membrane caveolae (caveolin-1) in the haploinsufficiency mechanism. GO cellular components: plasma membrane caveola, cytosol.
• Lateralization: systemic/bilateral; abscesses and necrotic lesions are focal/multifocal.

8. Temporal Development

• Onset: Classical recessive — neonatal to early infancy (first weeks of life; often premature birth, HP:0001622). Atypical/late-onset recessive — childhood (e.g. 7 y; or 1–4 y in the p.V185F families). Haploinsufficiency necrosis — typically adolescence, trigger-dependent.
• Onset pattern: recurrent/episodic flares of systemic inflammation (recessive); acute trigger-provoked necrotic crises (haploinsufficiency).
• Progression: without effective therapy, potentially fatal (septicaemia, multiorgan inflammation, renal failure, pulmonary edema — deaths at 16 mo and 5 y in the founding Pakistani family, PMID:27523608; a fatal Iranian splice-variant case). Chronic relapsing course with growth failure and lipodystrophy if untreated; liver disease can progress steatosis→fibrosis→HCC.
• Remission: treatment-induced remission achievable with anti-TNF/anti-IL-1 (recessive) and with HSCT (see §12). Haploinsufficiency episodes are acute and recurrent.
• Critical window: early diagnosis and TNF blockade (or definitive HSCT) before irreversible organ damage.

9. Inheritance and Population

• Inheritance: Autosomal recessive for classical ORAS/otulipenia (ClinGen Gene–Disease Validity: OTULIN – AIPDS, AR, Definitive, Monogenic Autoinflammatory Disease GCEP, 2026-05-19). Autosomal dominant for OTULIN haploinsufficiency and for the dominant-negative variants (p.C129S, p.R306Q).
• Penetrance: complete-to-high for biallelic LOF; incomplete (~30%) for haploinsufficiency, modified by anti-α-toxin antibodies (PMID:35587511: "3 of 10" ORAS-parent carriers had a milder phenotype).
• Expressivity: variable (classical vs atypical/fulminant; isolated PG).
• Consanguinity: major driver of recessive cases (Arab, Turkish, Pakistani, Iranian, Moroccan consanguineous families).
• Carrier/allele frequency: cumulative deleterious-allele frequency ≈ 6×10⁻⁵ (haploinsufficiency alleles; PMID:35587511).
• Epidemiology: Orphanet prevalence "Not yet documented"; ultra-rare, <50 classical patients reported worldwide. Orphanet notes "At least four cases" originally; literature now totals a few dozen across both forms. No reliable incidence/prevalence per 100,000 exists. PrevalenceClass suggestion: NOT_YET_DOCUMENTED; qualitative ULTRA_RARE.
• Founder effects: recurrent ancestry-specific homozygous variants reflect consanguinity rather than classic founder haplotypes. Sex ratio: no sex bias established (X-autosome: gene is autosomal). Geographic: cases concentrated in consanguineous populations of the Middle East, North Africa, South Asia, Turkey; haploinsufficiency cases more geographically dispersed.

10. Diagnostics

• Laboratory (LOINC-codable): persistently elevated CRP and ESR, leukocytosis/neutrophilia, thrombocytosis, elevated serum proinflammatory cytokines (TNF, IL-6, IL-18, IL-1β), hypergammaglobulinemia and autoantibodies (ANA/dsDNA) in some; negative microbial cultures during sterile flares. Research assay: elevated free M1(linear)-linked polyubiquitin chains in patient leukocytes (diagnostic hallmark; PMID:27523608).
• Functional immunology: increased basal/LPS-stimulated cytokine production by patient monocytes; reduced LUBAC (HOIP/SHARPIN) in lymphocytes; NF-κB reporter assays showing reduced inhibition by mutant OTULIN.
• Histopathology: neutrophilic dermatosis / septal or lobular panniculitis, sometimes with small/medium-vessel vasculitis; sterile abscesses.
• Imaging: CT for pulmonary/splenic/hepatic abscesses; characterises necrotic lesions in haploinsufficiency.
• Genetic testing (diagnostic gold standard): single-gene OTULIN sequencing, autoinflammatory gene panels, or WES/WGS (most founding cases found by exome). Chromosomal microarray/karyotype where a 5p deletion (Cri-du-Chat phenocopy) is suspected. GTR lists clinical OTULIN testing.
• Clinical criteria: no formal consensus diagnostic criteria; diagnosis = compatible autoinflammatory phenotype + biallelic (or relevant heterozygous) pathogenic OTULIN variant + supportive functional data. Screened at autoinflammatory-disease registries (Infevers OTULIN variant database).
• Differential diagnosis: other relopathies/LUBAC defects (HOIL-1/RBCK1, HOIP/RNF31 deficiency), RIPK1 deficiency (PMID:31213653), DIRA (IL1RN), DITRA (IL36RN), CANDLE/PRAAS, Mevalonate kinase deficiency/HIDS, TRAPS, FMF, CINCA/NOMID, deficiency of ADA2, and (for necrosis form) primary necrotizing soft-tissue infection. Distinguishing feature: M1-polyubiquitin accumulation and OTULIN genotype.
• Screening: carrier/cascade testing in consanguineous families; prenatal/preimplantation testing feasible for known familial variants.

11. Outcome / Prognosis

• Mortality: historically high in untreated classical disease — e.g. two of three affected siblings in the founding family died (pneumococcal sepsis at 16 mo; systemic inflammation with ARF/pulmonary edema at age 5) before anti-TNF was available (PMID:27523608, full text); a homozygous splice-variant Iranian patient died. Haploinsufficiency necrosis is life-threatening during crises.
• With treatment: prognosis is substantially improved by TNF inhibition and transformed by HSCT (potentially curative for the hematopoietic-driven recessive disease). Patient V:2 (p.L272P) "alive at age 11 with well-controlled disease" on infliximab; HSCT gave "complete resolution of inflammatory symptoms" (PMID:30804083).
• Morbidity: growth failure/FTT, lipodystrophy, joint disease, recurrent abscesses, and (long-term) risk of hepatic fibrosis/HCC; necrotic tissue loss and post-surgical complications in haploinsufficiency.
• Prognostic factors: genotype (amorph vs hypomorph), time to diagnosis/treatment, organ involvement (liver, lung), anti-α-toxin antibody status (haploinsufficiency penetrance). No validated prognostic biomarker beyond inflammatory markers and M1-Ub load.

12. Treatment

Suggested NCIT terms in brackets; most pharmacotherapy uses generic action NCIT:C15986 (Pharmacotherapy) + a therapeutic_agent.

• TNF inhibitors — mainstay of recessive ORAS. "treatment with anti-TNF neutralizing antibodies ameliorates inflammation in ORAS patients and rescues mouse phenotypes" (PMID:27523608).
• Infliximab [NCIT:C1789] — complete response in p.L272P patient (resolution within ~1 month; PMID:27559085).
• Adalimumab [NCIT:C65216] — remission in the AlSaleem p.V185F patients (monotherapy maintenance; PMID:40734169).
• Etanercept [NCIT:C2381] — partial response (p.G174fs; PMID:27559085). Therapeutic modality: MONOCLONAL_ANTIBODY (infliximab/adalimumab) vs soluble receptor (etanercept).
• Fasciitis/skin necrosis in haploinsufficiency: "excessive inflammation in OTULIN haploinsufficiency can be effectively treated by TNF inhibition" (Arts, PMID:38129331); post-operative necrosis improved on glucocorticoids + infliximab (PMID:40084498).
• IL-1 inhibition — variable. Anakinra [NCIT:C38717] gave complete response in one Turkish patient (p.Y244C) but was ineffective in others; canakinumab [NCIT:C80971] precipitated macrophage activation syndrome in one patient (PMID:27559085). IL-1β blockade proposed for the PG phenotype (PMID:42297973).
• Glucocorticoids [NCIT:C2323 / prednisolone NCIT:C769, prednisone NCIT:C770] — control acute flares; used as bridge/adjunct.
• Other immunomodulators: methotrexate [NCIT:C642] (adjunct to infliximab), azathioprine (ineffective alone), ruxolitinib [NCIT:C77888] (JAK inhibitor, tried in a dominant case).
• mTOR inhibition (mechanistic rationale, hepatic): rapamycin/sirolimus [NCIT:C1212; CHEBI:9168] reduced liver pathology in OTULIN-deficient mice — a candidate for hepatic involvement, not yet standard clinical practice (PMID:32231246).
• Definitive / curative: Allogeneic HSCT [NCIT:C46089 / Hematopoietic Cell Transplantation NCIT:C15431] — complete resolution in a transplanted ORAS patient; rationale that "haematopoietic cells are necessary for clinical manifestation of ORAS" (PMID:30804083). (Note: one literature case failed HSCT and responded instead to etanercept — PMID:40734169 Table.)
• Haploinsufficiency-specific supportive care: aggressive antibiotic therapy [NCIT:C15620] for staphylococcal infection, surgical debridement [NCIT:C51682] of necrotic tissue, and proposed (investigational) α-toxin-neutralizing monoclonal antibodies ± steroids (PMID:35587511). ADAM10 inhibition / cyclodextrin protected cells in vitro only.
• Genetic counseling [NCIT:C15240] for families (AR recurrence risk, consanguinity).

Treatment strategy: distinguish the two diseases — recessive ORAS → cytokine blockade (TNF first-line) ± HSCT; haploinsufficiency → trigger avoidance, prompt anti-staphylococcal therapy, TNF blockade for the hyperinflammatory component. Pharmacogenomics: none established.

13. Prevention

• Primary: no population prevention; genetic counseling and carrier/cascade screening in consanguineous families; prenatal/preimplantation genetic diagnosis for known familial variants.
• Secondary: early genetic diagnosis in a neonate/infant with recurrent fever + neutrophilic panniculitis + FTT, enabling early anti-TNF before organ damage.
• Tertiary: chronic cytokine blockade to prevent flares; hepatic surveillance (steatosis→HCC risk); for haploinsufficiency — trigger avoidance (wound/surgical prophylaxis, prompt treatment of S. aureus), and antibody-mediated protection concepts.
• Immunization: no disease-specific vaccine; standard immunisation with attention to live-vaccine caution under biologics; anti-α-toxin vaccination is a theoretical research direction for haploinsufficiency.

14. Other Species / Natural Disease

• Taxonomy: mechanistic/genetic models in mouse (Mus musculus, NCBITaxon:10090). The gene was first characterised in mouse as gumby/*Fam105b (Rivkin et al., Nature 2013, PMID:23708998 — angiogenesis/Otulin developmental role). Human pathogen relevant to the haploinsufficiency form: Staphylococcus aureus* (NCBITaxon:1280).
• Orthologous gene: mouse Otulin (Entrez 71753). Strong evolutionary conservation of the OTU domain and M1-Ub machinery (LUBAC/OTULIN axis conserved across vertebrates).
• Natural animal disease: no naturally occurring OTULIN autoinflammatory disease is catalogued in OMIA for companion animals/livestock (based on this literature review); disease knowledge in animals is from engineered models, not spontaneous disease.
• Comparative pathology caveat: mouse haploinsufficiency inflammation is hematopoietic-driven, whereas human haploinsufficiency necrosis is non-hematopoietic/stromal — an explicit human–model mismatch (PMID:38827742 vs 35587511), important for KB HUMAN_MODEL_MISMATCH annotation.
• Zoonosis: not applicable (the disease is genetic; the trigger S. aureus is a common commensal/pathogen, not a zoonotic transmission of the disease).

15. Model Organisms

• Germline knockout mouse (Otulin LacZ / gumby): homozygous loss is embryonic lethal (~E12.5–E14), with angiogenesis/Wnt defects (PMID:23708998; PMID:27523608 full text). Models early developmental OTULIN function; not viable for inflammation study.
• Catalytically inactive knock-in (Otulin C129A/gumby-type): Heger et al. (Nature 2018, PMID:29950720) — "Catalytically inactive OTULIN knock-in mice died midgestation from TNFR1- and RIPK1-kinase-dependent cell death"; rescued by co-deletion of Casp8/Ripk3; elevated type I IFN. Establishes OTULIN restrains LUBAC and limits cell death/inflammation.
• Conditional (Cre-lox) tissue-specific deletions (key for dissecting cell-type contributions; PMID:27523608 full text):
• LysM-Cre (myeloid): viable; splenomegaly/hepatomegaly, leukocytosis, elevated serum cytokines (TNF, IL-6, IL-1β, G-CSF), fibrosis, autoantibodies — recapitulates systemic autoinflammation.
• CD4-Cre (T cell) and MB1-Cre (B cell): no overt inflammatory phenotype → inflammation is myeloid-driven.
• CreERT2 (tamoxifen-inducible, bone-marrow chimera): rapid wasting, neutrophilia, high TNF/IL-6/G-CSF; anti-TNF prevents wasting — supports anti-TNF efficacy.
• Epidermis-specific (keratinocyte): skin inflammation via TNFR1/RIPK1-kinase-dependent necroptosis (Schünke, Nat Commun 2021, PMID:34625557).
• Hepatocyte-specific: steatohepatitis→fibrosis→HCC, FADD/RIPK1-dependent, mTOR-associated (PMID:32231246, 32075762).
• Myeloid (RIPK3/Nlrp3 axis): PMID:38000038.
• Haploinsufficient mouse (Otulin+/−): LPS-provoked hyperinflammation driven by CD64+ monocytes/macrophages — but hematopoietic-driven, unlike human (PMID:38827742) — a documented translational limitation.
• Patient iPSC model: iPSC line from a patient homozygous for L272P (Chen, Stem Cell Res 2020, PMID:32721894; line NIHTVBi014-A) — a human cellular NAM for mechanism/drug studies.
• Resources: MGI (mouse Otulin), IMPC/KOMP (knockout alleles), Cellosaurus (iPSC line).
• Model recapitulation summary: tissue-specific conditional KOs faithfully reproduce organ-specific disease (skin, liver, myeloid inflammation) and validate TNF/RIPK1 as drivers; whole-body null is lethal (developmental confounder); haploinsufficiency mouse diverges from the human stromal/α-toxin mechanism.

Key Evidence Citations (PMIDs)

Curation notes / flags for KB entry

1. The existing kb/disorders/OTULIN-Related_Autoinflammatory_Syndrome.yaml is a bare skeleton (name, synonyms, MONDO:0014912, one empty pathophysiology node, one phenotype stub) with no evidence. This report provides the content to populate it.
2. Two (arguably three) distinct diseases share this gene. Recommend modelling classical recessive ORAS as the primary entry, with OTULIN haploinsufficiency either as a has_subtypes stratum or (given two divergent axes — inheritance AD vs AR, and a distinct stromal/α-toxin mechanism and necrosis phenotype) a candidate separate entry per the Mendelian lump/split rules. Capture the dominant-negative heterozygous ORAS (C129S, R306Q) via an Inheritance block + variant_origin/functional_impact_category: DOMINANT_NEGATIVE.
3. Inheritance: bind AR as primary (ClinGen Definitive, AR, 2026-05-19 — record as gene_disease_validity with classified_by: CLINGEN, quoting the CGGV row after fetching it). Add a separate AD mode for haploinsufficiency.
4. Human–model mismatch (PMID:38827742 vs 35587511) is a clean HUMAN_MODEL_MISMATCH discussion candidate.
5. Cancer link: hepatocellular carcinoma via chronic hepatocyte death (mouse + case) — note but do not over-claim in humans (single patient with steatotic liver disease, HCC shown in mouse).
6. Before curating: run just fetch-reference for each PMID above, ORPHA:500062, and the ClinGen CGGV assertion; verify every snippet as an exact substring per the dismech-references workflow (the short quotes in this report are abstract/full-text excerpts gathered via EuropePMC and must be re-verified against the fetched cache before use as evidence snippet: values).

Sources: Orphanet ORPHA:500062 / Infevers · MONDO:0014912 (OLS4) · ClinGen OTULIN (HGNC:25118) · MalaCards AIPDSB · PubMed/EuropePMC records for the PMIDs cited above.

Reference Validation

Checked with linkml-reference-validator 0.4.0.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• NCIT:C15620 (1 mention) - the report calls it "antibiotic therapy", "Haploinsufficiency-specific supportive care: aggressive antibiotic therapy"; NCIT calls it Antibiotic Therapy

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

• MONDO:0014912 (9 mentions) - the report calls it "OLS4"; MONDO calls it autoinflammation, panniculitis, and dermatosis syndrome, autosomal recessive, and lists "ORAS" among its other names
• HP:0031281 (1 mention) - the report calls it "Sialadenitis / parotitis"; HP calls it Sialadenitis
• HP:0025452 (2 mentions) - the report calls it "Pyoderma gangrenosum (R57C only)"; HP calls it Pyoderma gangrenosum
• NCIT:C642 (1 mention) - the report calls it "Other immunomodulators: methotrexate"; NCIT calls it Methotrexate**

Terms named inconsistently

The report gives these identifiers more than one name of its own:

• NCIT:C15620 - called "antibiotic therapy", "Haploinsufficiency-specific supportive care: aggressive antibiotic therapy"

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: OMIM, ORPHA.