NIK Deficiency (MONDO:0018642): A Comprehensive Disease Characteristics Report

Summary

NIK Deficiency is an ultra-rare, autosomal-recessive combined primary immunodeficiency caused by biallelic loss-of-function mutations in MAP3K14 (HGNC:6853; NCBI Gene 9020; OMIM *604655; Ensembl ENSG00000006062; UniProt Q99558; chr17q21.31), the gene encoding NIK (NF-κB–inducing kinase). NIK is the apical, rate-limiting kinase of the non-canonical (alternative) NF-κB pathway. Disease arises when both alleles carry a kinase-inactivating mutation, abolishing NIK's ability to drive IKKα-mediated processing of the NF-κB2 precursor p100 into active p52, and consequently crippling RelB/p52-dependent transcription. Because NIK also feeds forward into prolonged canonical NF-κB signaling, patients have defects in both arms of the pathway.

The clinical consequence is a multifaceted combined immunodeficiency. The index report (Willmann et al. 2014, PMID: 25406581) described patients with recurrent bacterial, viral, and Cryptosporidium infections, who exhibited B-cell lymphopenia, decreased class-switched memory B cells, hypogammaglobulinemia, impaired ICOSL expression, perturbed follicular-helper (Tfh) and memory T cells, and decreased/defective NK cells with impaired immunological-synapse formation. The disease belongs to a tightly related family of non-canonical NF-κB inborn errors of immunity (alongside NFKB2, RELB, and CHUK/IKKα defects) that share a striking predisposition to neutralizing autoantibodies against type I interferon.

NIK deficiency sits at the loss-of-function pole of a bidirectional, dose-dependent NIK disease axis: too little NIK produces immunodeficiency, while excess NIK activity drives autoimmunity, cancer, sterile inflammation, fibrosis, and metabolic disease (Valiño-Rivas et al. 2019, PMID: 30926358). Diagnosis currently rests on functional validation of kinase activity because no pathogenic MAP3K14 variants are deposited in ClinVar, and the gene is strongly loss-of-function–intolerant in the general population (gnomAD pLI ≈ 1.0) yet the disease is recessive. Allogeneic hematopoietic stem cell transplantation (HSCT) can reconstitute the hematopoietic immune compartment but does not repair the radioresistant stromal/thymic architectural defects, so lifelong immunologic and anti-cytokine autoantibody surveillance is required (Köstel Bal et al. 2025, PMID: 41280889).

This report synthesizes 8 confirmed findings across 34 reviewed papers into a comprehensive disease-knowledge-base entry covering all 15 requested domains. Where primary human data are sparse (reflecting the extreme rarity of the disorder), mechanism is supported by an extensive murine and in vitro literature, and these evidence levels are flagged throughout.

Key Findings

F001 — NIK deficiency is a biallelic MAP3K14 loss-of-function primary immunodeficiency

Willmann et al. (2014) identified a biallelic mutation in MAP3K14 (NIK) in patients presenting with recurrent bacterial, viral, and Cryptosporidium infections. The mutation abolishes NIK kinase activity, which was "predicted by in silico analysis and confirmed by functional assays" and "leads to defective activation of both canonical and non-canonical NF-κB signalling" (PMID: 25406581). The immunological phenotype is broad and spans all three major lymphocyte lineages: B-cell lymphopenia, decreased class-switched memory B cells, hypogammaglobulinemia (reflecting impaired B-cell survival), impaired ICOSL expression, perturbed Tfh and memory T-cell compartments, and decreased/defective NK cells with impaired immunological-synapse formation. This single landmark paper establishes the causal gene, the recessive (biallelic) inheritance, and the core molecular lesion — loss of NIK kinase activity — that defines the disease.

Evidence level: Human clinical + in vitro functional assay.

F002 — NIK is the rate-limiting kinase of the non-canonical NF-κB pathway, controlling p100→p52/RelB processing

NIK (MAP3K14) is normally held at vanishingly low levels by constitutive degradation through the TRAF2–TRAF3–cIAP1/2 ubiquitin-ligase complex. Engagement of TNF-receptor-superfamily receptors — BAFFR, CD40, LTβR, RANK, and Fn14 — triggers TRAF3 degradation, which stabilizes and allows NIK to accumulate. Accumulated NIK phosphorylates IKKα, which in turn phosphorylates NF-κB2/p100, driving its proteasomal processing to p52 and the nuclear translocation of RelB/p52 heterodimers. Senftleben et al. (2001) established the kinase hierarchy: "IKKalpha is required for B cell maturation, formation of secondary lymphoid organs, increased expression of certain NF-kappaB target genes, and processing of the NF-kappaB2 (p100) precursor. IKKalpha preferentially phosphorylates NF-kappaB2, and this activity requires its phosphorylation by upstream kinases, one of which may be NF-kappaB-inducing kinase (NIK)" (PMID: 11520989). Dash et al. (2020) showed in multiple myeloma that lower TRAF3 expression and higher NIK expression mark pathway activation (PMID: 32350909). In NIK-deficient patients, kinase-dead NIK abolishes p100→p52 processing, collapsing the entire downstream axis.

Evidence level: In vitro / model organism (mechanistic hierarchy); human (disease relevance).

F003 — Mouse models (aly/aly, NIK KO, conditional) recapitulate the lymphoid defects

The spontaneous alymphoplasia (aly/aly) mouse carries a loss-of-function point mutation in Nik/Map3k14 and displays absence of lymph nodes and Peyer's patches, disrupted lymphoid architecture, and impaired B-cell formation and immunoglobulin production. Ozcan et al. (2026) summarize: "NIK deficiency causes loss of lymph nodes, disruption of lymphoid organ structure and deficits in B-cell formation and immunoglobulin production" (PMID: 42175627). Conditional deletion of NIK in adult mice reduces B-cell populations and germinal-center B cells and abrogates BAFF responses: "Germline deletion or inactivation of NIK in mice results in the defective development of B cells and secondary lymphoid organs" (Brightbill et al. 2015, PMID: 26116508). NIK additionally supports medullary and cortical thymic-epithelial-cell development (Eshima et al. 2020, PMID: 32145062) and has a cell-intrinsic role in effector/memory T-cell generation (Li et al. 2016, PMID: 26912039). The murine models thus faithfully reproduce the B-cell, secondary-lymphoid-organ, and thymic-architectural defects seen in patients.

Evidence level: Model organism (mouse).

F004 — The NIK kinase domain is structurally characterized, active-like without phosphorylation, with a narrow flexible active site

Crystal structures of the apo NIK catalytic domain (both human and murine) reveal an active-like conformation in the absence of phosphorylation. de Leon-Boenig et al. (2012) report: "Structures of the apo NIK kinase domain from both species reveal an active-like conformation in the absence of phosphorylation. ATP consumption and peptide phosphorylation assays confirm that phosphorylation of NIK does not increase enzymatic activity" (PMID: 22921830). The active site is narrow with a flexible gatekeeper residue. This structural biology explains two important facts about the disease: (1) NIK is regulated primarily by protein abundance (stabilization), not by activation-loop phosphorylation, so loss-of-function in disease is achieved by missense mutations that destroy catalytic competence or protein stability rather than by blocking an activating phosphorylation; and (2) the well-defined ATP pocket has enabled structure-based inhibitor design (Li et al. 2013, PMID: 23374866), relevant to the gain-of-function end of the disease axis.

Evidence level: Computational/structural + in vitro biochemistry.

F005 — NIK deficiency belongs to the non-canonical NF-κB IEI family that shares anti–type I IFN autoantibody predisposition

Human inborn errors of the non-canonical NF-κB axis — NFKB2 (p100), RELB, CHUK/IKKα, and MAP3K14/NIK — produce overlapping combined immunodeficiency with hypogammaglobulinemia. A clinically important shared feature is neutralizing autoantibodies against type I interferon. Riller et al. (2025) reported that IKKα (CHUK) kinase-domain–deficient patients have diminished non-canonical (and partially impaired canonical) NF-κB with "neutralizing autoantibodies against type I IFN, akin to non-canonical NF-κB pathway deficiencies" (PMID: 39812688). RelB deficiency likewise "disrupts the non-canonical NF-κB pathway, underlying a T- and B cell immunodeficiency, which, together with neutralizing autoantibodies against type I IFNs" (Moriya 2026, PMID: 42261849). Consistent with membership in this family, the NIK-deficiency HSCT follow-up study emphasized monitoring for anti-cytokine autoantibodies (PMID: 41280889). This predisposition likely reflects failure of central/peripheral tolerance mechanisms that depend on non-canonical NF-κB (AIRE-dependent medullary thymic epithelial cell function).

Evidence level: Human clinical (family of disorders).

F006 — NIK dosage determines disease direction: loss → immunodeficiency; overactivity → autoimmunity/cancer/fibrosis

NIK sits at the center of a bidirectional, dose-dependent disease axis. Valiño-Rivas et al. (2019) frame NIK as the apical non-canonical NF-κB kinase whose disease spectrum "now ranges from immunodeficiency (when NIK is defective) to autoimmunity, cancer, sterile inflammation, fibrosis, and metabolic disease when NIK is overactive" (PMID: 30926358). NIK deficiency occupies the loss-of-function pole. The physiological processes placed at risk by NIK loss are enumerated by Liu et al. (2019): "The non-canonical NF-κB signalling cascade is essential for lymphoid organogenesis, B cell maturation, osteoclast differentiation, and inflammation in mammals" (PMID: 30894749). NIK also drives prolonged canonical NF-κB via IKKα/β in endothelium (Kucharzewska et al. 2019, PMID: 30837284), explaining the combined-pathway defect. TRAF2, the upstream NIK regulator, stimulates NK-cell cytotoxicity (Albini et al. 2025, PMID: 40229245), consistent with the NK defect observed in patients.

Evidence level: Review synthesis + model organism + human.

F007 — Gene identifiers confirmed; ClinVar holds no pathogenic MAP3K14 variants

Programmatic verification established: MAP3K14 = HGNC:6853, NCBI Gene 9020, OMIM *604655, Ensembl ENSG00000006062, UniProt Q99558, cytoband 17q21.31, GRCh38 chr17:45,263,119–45,317,112 (minus strand), RefSeq NM_003954.5. A ClinVar query (MAP3K14[gene]) returned 30 variant records, all classified VUS or Likely benign (e.g., p.Ser97Ter VUS; p.Val828fs VUS); zero Pathogenic/Likely-pathogenic entries. The disease-causing biallelic kinase-domain variants described in patients are not deposited in ClinVar as pathogenic. This is a critical practical point: a clinical diagnosis cannot currently rely on a ClinVar pathogenicity lookup and must instead be anchored by functional kinase-activity assays, exactly as in the index report where pathogenicity was "predicted by in silico analysis and confirmed by functional assays" (PMID: 25406581).

Evidence level: Database verification (computational) + human.

F008 — MAP3K14 is strongly LoF-intolerant in gnomAD (pLI ≈ 1.0), yet the disease is recessive

gnomAD constraint metrics for MAP3K14 (GRCh38) are: pLI = 1.00, observed/expected LoF = 0.16 (LOEUF 90% CI 0.11–0.24), LoF Z = 7.09, missense Z = 5.21 — indicating strong depletion of both predicted-LoF and missense variation in the general population. The apparent paradox — a haploinsufficiency-intolerant gene causing a recessive disease — is resolved by the biology: heterozygous carrier parents are clinically unaffected (Willmann et al. 2014, PMID: 25406581), so the immunodeficiency requires biallelic loss, while the high population constraint likely reflects strong selection against loss in combination with the fact that NIK overactivity (the other pole of the axis) is also deleterious — tight dosage control is evolutionarily favored in both directions.

Evidence level: Population genetics (computational) + human.

Detailed Section-by-Section Report

1. Disease Information

Overview. NIK deficiency is a Mendelian, autosomal-recessive combined primary immunodeficiency / inborn error of immunity caused by biallelic loss-of-function mutations in MAP3K14, which encodes NF-κB–inducing kinase (NIK). The disorder produces a multifaceted defect of lymphoid immunity affecting B cells, T cells, and NK cells, together with structural defects of secondary lymphoid organs and thymic epithelium, clinically manifesting as recurrent bacterial, viral, and Cryptosporidium infections.

Key identifiers.

Synonyms / alternative names. MAP3K14 non-severe combined immunodeficiency; non-severe combined immunodeficiency caused by mutation in MAP3K14; primary immunodeficiency with multifaceted aberrant lymphoid immunity; NIK deficiency.

Source of information. The disease-level knowledge is derived from a small number of individual patient reports (index family, Willmann et al. 2014; HSCT long-term follow-up, Köstel Bal et al. 2025) supplemented by aggregated gene/variant resources (OMIM, ClinVar, gnomAD) and an extensive model-organism and in vitro mechanistic literature. There is no large aggregated clinical registry given the disorder's rarity.

2. Etiology

Primary cause — genetic. Biallelic loss-of-function mutations in MAP3K14 abolishing NIK kinase activity (F001). The index variant was a kinase-domain mutation confirmed functionally (PMID: 25406581).

Genetic risk factors. The disease is monogenic and fully penetrant with biallelic LoF; there is no evidence for susceptibility loci or modifier genes in humans (too few patients). Carrier status (heterozygous) confers no known clinical risk. Consanguinity is a strong contextual risk factor as for most ultra-rare recessive disorders.

Environmental / infectious contributors. Environmental factors do not cause the disease but act as the trigger for clinical presentation: encapsulated bacteria, herpesviruses (e.g., CMV), and the opportunistic protozoan Cryptosporidium are the organisms that exploit the immune defect. Cryptosporidium infection with potential hepatobiliary involvement is a hallmark that overlaps with other T-cell/combined immunodeficiencies.

Protective factors. None specific are documented. In principle, a functional second MAP3K14 allele (heterozygosity) is fully protective, consistent with recessive inheritance (F008).

Gene–environment interactions. The core interaction is permissive: the genetic lesion removes host defense, and environmental pathogen exposure determines the timing, severity, and organ pattern of disease. No classical GxE modifier data exist.

3. Phenotypes

Phenotypes are drawn primarily from the index clinical report (F001) and HSCT follow-up (F005). Frequencies are qualitative given the tiny cohort.

Quality-of-life impact. Chronic/recurrent infections and chronic diarrhea with hepatobiliary disease substantially impair growth, nutrition, and daily functioning. No formal EQ-5D/SF-36/PROMIS data exist for this ultra-rare disorder.

4. Genetic / Molecular Information

Causal gene. MAP3K14 / NIK (identifiers in Section 1; F007).

Pathogenic variants. The index disease allele is a kinase-domain mutation causing loss of NIK catalytic activity, validated functionally (F001). No pathogenic or likely-pathogenic MAP3K14 variants are currently in ClinVar (30 records, all VUS/likely-benign; F007). Variant classes expected to cause disease: missense within the kinase domain (as in the index case), and in principle nonsense, frameshift, and splice-site biallelic LoF alleles. All are germline. Functional consequence: loss of function (kinase-dead), impairing both non-canonical and canonical NF-κB (F001, F006).

Allele frequency / constraint. MAP3K14 is strongly LoF-intolerant: pLI = 1.00, o/e LoF = 0.16 (LOEUF 0.11–0.24), LoF Z = 7.09, missense Z = 5.21 (gnomAD; F008). Disease-causing alleles are private/ultra-rare.

Modifier genes / epigenetics / chromosomal abnormalities. No human modifier genes, disease-specific epigenetic marks, or chromosomal abnormalities are documented for NIK deficiency. (Note: in cancers, non-canonical NF-κB activation can occur via MAP3K14 dysregulation — e.g., S100A14/UPF1-mediated stabilization of MAP3K14/NFKB2/RELB transcripts, PMID: 42350366 — but this is the opposite, gain-of-activity pole and not the inherited deficiency.)

5. Environmental Information

• Environmental/occupational toxins, radiation, pollution: Not implicated in disease causation.
• Lifestyle factors: Not applicable (monogenic disorder).
• Infectious agents: Central to clinical expression. Key organisms include encapsulated bacteria, viruses (notably CMV and other herpesviruses), and the protozoan Cryptosporidium (NCBI Taxonomy: Cryptosporidium genus), which causes chronic diarrhea and can involve the hepatobiliary tract in immunodeficient hosts. These are opportunistic consequences of the immune defect, not causes of the mutation.

6. Mechanism / Pathophysiology

Ordered causal chain (initiating lesion → clinical manifestation):

1. Biallelic LoF mutation in MAP3K14 → produces a kinase-dead NIK protein (demonstrated: in silico + functional assays, PMID: 25406581).
2. Kinase-dead NIK fails to phosphorylate IKKα upon TNF-receptor-superfamily engagement (BAFFR, CD40, LTβR, RANK, Fn14) → results in failure of IKKα to phosphorylate p100 (demonstrated mechanistically, PMID: 11520989).
3. Unphosphorylated p100 is not processed to p52 → leads to loss of nuclear RelB/p52 heterodimer transcription (non-canonical NF-κB collapse).
4. NIK loss also impairs sustained canonical NF-κB (NIK–IKKα/β interaction) → results in a combined two-pathway defect (PMID: 30837284; PMID: 25406581).
5. Branch A — Stromal/structural: Loss of LTβR→NIK→RelB/p52 signaling in stromal and epithelial cells → leads to absent/hypoplastic lymph nodes, Peyer's patches, disrupted splenic architecture, and defective thymic epithelial cell development (demonstrated in mouse; PMID: 42175627, PMID: 32145062).
6. Branch B — B cells: Loss of BAFFR/CD40→NIK signaling → leads to impaired B-cell survival and maturation → results in B-cell lymphopenia, decreased class-switched memory B cells, and hypogammaglobulinemia (PMID: 26116508; PMID: 25406581).
7. Branch C — T cells: Cell-intrinsic NIK loss → impairs effector/memory T-cell generation and Tfh function → contributes to impaired antibody help and ICOSL dysregulation (PMID: 26912039).
8. Branch D — NK cells: NIK/TRAF2-axis loss → leads to decreased/defective NK cells with impaired immunological-synapse formation (PMID: 25406581; PMID: 40229245).
9. Branch E — Tolerance (inferred): Impaired AIRE-dependent medullary thymic epithelial function → predisposes to neutralizing anti–type I IFN autoantibodies (inferred from shared non-canonical NF-κB IEI family; PMID: 39812688, PMID: 42261849).
10. Combined cellular and structural defects → result in the clinical phenotype: recurrent bacterial/viral/Cryptosporidium infections, with chronic diarrhea and hepatobiliary disease.

Molecular pathways (Reactome/KEGG): Non-canonical NF-κB signaling (Reactome R-HSA-5676590); canonical NF-κB; TNF-receptor-superfamily signaling.

Cellular processes & GO terms: NIK/NF-κB-inducing kinase activity (GO:0004704 MAP kinase kinase kinase activity); positive regulation of NF-κB transcription factor activity (GO:0051092); B-cell homeostasis (GO:0001782); lymph node development (GO:0048535); I-κB kinase/NF-κB signaling (GO:0007249).

Protein dysfunction: Loss of kinase function in an otherwise constitutively active-like kinase domain regulated by abundance (F004, PMID: 22921830).

Immune system involvement: Combined immunodeficiency (B, T, NK) plus autoimmune/tolerance predisposition (F005).

Molecular profiling: In myeloma, low TRAF3 + high NIK expression mark pathway activation (PMID: 32350909) — a useful readout of the axis, though from the opposite (gain) pole.

Upstream vs downstream: Mutation (upstream) → NIK kinase failure → IKKα → p100/p52 (midstream) → RelB/p52 transcriptional programs in B cells, stroma, TECs, T cells, NK cells (downstream) → clinical infection susceptibility.

7. Anatomical Structures Affected

• Organ level (primary): Secondary lymphoid organs — lymph nodes (UBERON:0000029), spleen (UBERON:0002106), Peyer's patches / gut-associated lymphoid tissue (UBERON:0001211); thymus (UBERON:0002370, thymic epithelium); bone marrow (UBERON:0002371).
• Secondary involvement: Gastrointestinal tract (chronic Cryptosporidium diarrhea; UBERON:0000160) and hepatobiliary system / bile ducts (sclerosing cholangitis; UBERON:0002394).
• Body systems: Immune/hematolymphoid system (primary); digestive and hepatobiliary systems (secondary).
• Tissue/cell level (Cell Ontology): B cells (CL:0000236), including class-switched memory B cells; T cells (CL:0000084), follicular-helper and memory subsets; NK cells (CL:0000623); thymic epithelial cells (CL:0002293); lymphoid stromal cells.
• Subcellular (GO cellular component): Cytoplasm (GO:0005737, where NIK acts upstream of IKK), nucleus (GO:0005634, RelB/p52 translocation target).
• Lateralization: Systemic/bilateral; not a lateralized disorder.

8. Temporal Development

• Onset: Early — congenital immune architecture defects present from development; clinical infections in infancy/childhood. Onset pattern is chronic/insidious with recurrent acute infectious episodes.
• Progression: Without immune reconstitution, the course is a chronic, lifelong combined immunodeficiency with recurrent and opportunistic infections; organ damage (e.g., sclerosing cholangitis) can be progressive and severe.
• Course pattern: Chronic with episodic infectious exacerbations.
• Remission: No spontaneous remission; treatment-induced immune reconstitution is achievable with HSCT for the hematopoietic compartment, but the radioresistant stromal/thymic architectural defects persist after transplant (PMID: 41280889).
• Critical period: Early diagnosis and transplant before cumulative infectious/organ damage is the key window of intervention.

9. Inheritance and Population

• Epidemiology: Ultra-rare; only a handful of genetically confirmed cases worldwide. No reliable prevalence/incidence estimates exist.
• Inheritance: Autosomal recessive; requires biallelic LoF. Heterozygous carriers are unaffected (F001, F008).
• Penetrance / expressivity: Presumed complete penetrance with biallelic LoF; expressivity across the few cases includes the core lymphoid/infectious phenotype.
• Anticipation / mosaicism: Not applicable / not reported.
• Founder effects / consanguinity: No founder allele established; consanguinity is the expected context for recessive presentation. Carrier frequency is extremely low, consistent with strong gnomAD constraint (F008).
• Demographics: No ethnic predilection established; too few cases for sex-ratio or geographic analysis.

10. Diagnostics

Diagnostic approach. Because no pathogenic MAP3K14 variants are catalogued in ClinVar (F007), diagnosis rests on a combination of genetic sequencing + functional validation:

• Genetic testing: Whole-exome (WES) or whole-genome sequencing (WGS) is the practical route to identify biallelic MAP3K14 variants, often via GeneMatcher-style collaboration given rarity. Targeted single-gene or inborn-errors-of-immunity (IEI) gene panels that include MAP3K14 are appropriate. CMA/karyotyping/FISH are not primary tools (no chromosomal mechanism).
• Functional confirmation (essential): Assays of NIK kinase activity and p100→p52 processing in patient cells/transfected constructs — the strategy used in the index report (PMID: 25406581).
• Immunophenotyping (laboratory): Flow cytometry showing B-cell lymphopenia, reduced class-switched memory B cells, reduced/defective NK cells, and perturbed memory/Tfh T cells; serum immunoglobulins showing hypogammaglobulinemia.
• Autoantibody screen: Test for neutralizing anti–type I IFN autoantibodies (shared family feature; F005).
• Infectious work-up: Stool microscopy/antigen for Cryptosporidium; CMV viral load; imaging (MRCP) if cholangitis suspected.

Differential diagnosis: Other combined immunodeficiencies and CVID-spectrum disorders, especially the related non-canonical NF-κB IEIs (NFKB2, RELB, CHUK/IKKα) and other causes of chronic Cryptosporidium infection (e.g., CD40L deficiency, IL-21R deficiency PMID: 33966600, DOCK8 deficiency PMID: 41695074). Distinguishing feature: combined B/T/NK defect with absent secondary lymphoid organs and NIK functional defect.

Screening: Not part of standard newborn screening (which detects T-cell lymphopenia via TRECs; NIK deficiency may be TREC-variable). Cascade/carrier testing in affected families is appropriate once the variant is known.

11. Outcome / Prognosis

• Survival/mortality: No formal survival statistics (ultra-rare). Prognosis without immune reconstitution is guarded due to recurrent/opportunistic infections and organ complications (e.g., sclerosing cholangitis).
• Morbidity: Substantial — chronic infections, chronic diarrhea/malnutrition, hepatobiliary disease.
• Disease course / complications: Progressive organ damage possible; CMV disease and Cryptosporidium-associated cholangitis are major threats.
• Recovery potential: HSCT can restore hematopoietic immunity (full donor chimerism and T-cell reconstitution reported) but does not repair the stromal/thymic architectural defects (PMID: 41280889).
• Prognostic factors: Early diagnosis, pre-transplant infection/organ-damage burden, and post-transplant immune dysregulation (including anti-cytokine autoantibodies) shape outcome.

12. Treatment

• Definitive therapy — allogeneic HSCT: The principal curative-intent treatment for the hematopoietic immune defect. Both reported patients achieved full donor chimerism and early T-cell reconstitution, but the authors stress the non-redundant, radioresistant role of non-canonical NF-κB in thymic reconstitution and secondary lymphoid organ development, which HSCT does not restore (PMID: 41280889). NCIT suggestion: Hematopoietic Stem Cell Transplantation (NCIT:C15431); Allogeneic Bone Marrow Transplantation (NCIT:C15335).
• Supportive pharmacotherapy: Immunoglobulin replacement therapy (IVIG/SCIG) for hypogammaglobulinemia (NCIT:C584 Immunoglobulin Therapy); antimicrobial prophylaxis against bacterial/viral/opportunistic pathogens; targeted treatment of Cryptosporidium (e.g., nitazoxanide) and CMV (e.g., ganciclovir/valganciclovir).
• Monitoring/adjunct: Long-term immunologic monitoring, including surveillance for immune dysregulation and anti-cytokine autoantibodies; the follow-up study suggests future consideration of thymic regeneration or targeted immune modulation to address architectural defects (PMID: 41280889).
• Gene/cell/RNA therapy: No approved gene therapy; MAP3K14 is a conceptual candidate for gene correction given the recessive LoF mechanism, but none exists clinically.
• Pharmacogenomics / NIK inhibitors: NIK inhibitors (e.g., Cpd33; PMID: 32169603) are relevant to the opposite (gain-of-function) pole of the axis (cancer, bone loss, inflammation) and are contraindicated in NIK deficiency.

13. Prevention

• Primary prevention: Not preventable at the level of the mutation; genetic counseling for consanguineous/affected families and reproductive options (preimplantation/prenatal testing once the variant is known).
• Secondary prevention: Early molecular diagnosis enabling pre-emptive antimicrobial prophylaxis, IgG replacement, and timely HSCT.
• Tertiary prevention: Infection prophylaxis, nutritional support, and surveillance/management of hepatobiliary disease and anti-cytokine autoantibodies to prevent complications.
• Immunization: Live vaccines are contraindicated; inactivated vaccines may give blunted responses due to antibody-production defects.
• Counseling: Genetic counseling with cascade carrier testing is central.

14. Other Species / Natural Disease

• Taxonomy / orthologs: Human MAP3K14 (NCBI Gene 9020); mouse ortholog Map3k14 / Nik (NCBI Gene 53859; Mus musculus, NCBI Taxon 10090).
• Natural animal disease: The alymphoplasia (aly/aly) mouse is a spontaneous natural Nik loss-of-function point mutant — the prototypical animal model (F003). No companion-animal (OMIA) natural disease is established.
• Comparative biology / conservation: The NIK→IKKα→p100/p52 non-canonical NF-κB axis and its role in lymphoid organogenesis, B-cell maturation, and osteoclast differentiation are conserved across mammals (PMID: 30894749), underpinning the strong translational value of mouse models.
• Zoonosis: Not applicable.

15. Model Organisms

Recapitulation & limitations. Mouse models faithfully reproduce the B-cell, secondary-lymphoid-organ, and thymic-architectural features of human disease and were instrumental in defining the pathway. Limitations: murine models may not capture the human anti–type I IFN autoantibody predisposition or the full NK-cell/Cryptosporidium susceptibility, and species differences in immune architecture mean phenotype severity does not map 1:1. Resources: MGI (mouse), with aly/aly as the canonical strain.

Mechanistic Model / Interpretation

  Biallelic MAP3K14 LoF mutation
    │  (kinase-dead NIK; functionally confirmed)
    ▼
  TNFRSF ligation (BAFFR/CD40/LTβR/RANK/Fn14)
  normally stabilizes NIK via TRAF3 degradation
    │  ── but kinase-dead NIK cannot act ──
    ▼
  NIK fails to phosphorylate IKKα
    ▼
  IKKα fails to phosphorylate p100 (NFKB2)
    ▼
  p100 NOT processed to p52  ──►  no nuclear RelB/p52
    │                         │
    │                         └── (also: impaired sustained canonical NF-κB)
    ▼
  ┌─────────┬─────────┬─────────┬─────────┬─────────────┐
  ▼         ▼         ▼         ▼         ▼             ▼
Stroma/   B cells   T cells   NK cells  Tolerance    Combined
TEC                                     (inferred)   two-pathway
  │         │         │         │         │           defect
absent LN/ B-lympho- impaired  defective anti-IFN-α
Peyer's,   penia,    effector/ NK +      autoAb
disrupted  low memory memory,  impaired  predisposition
thymus     B, hypo-  Tfh dys-  synapse
   gammaglob function
  └─────────┴─────────┴─────────┴─────────┴─────────────┘
                ▼
   Recurrent bacterial, viral (CMV), and Cryptosporidium
   infections; chronic diarrhea; sclerosing cholangitis

The bidirectional dosage axis (F006) frames NIK deficiency as one pole of a continuum:

This dosage logic explains the paradox of a recessive disease in a highly LoF-constrained gene (F008): evolution selects against both loss and excess, favoring tight control.

Evidence Base

Supporting/context papers (gain-of-function pole, differentials): PMID: 32169603 (NIK inhibitor, bone), PMID: 42350366 (CRC S100A14/MAP3K14), PMID: 33966600 (IL-21R differential), PMID: 41695074 (DOCK8 differential), PMID: 31709944 (Cryptosporidium context).

Limitations and Knowledge Gaps

1. Extremely few human cases. Essentially all human clinical knowledge derives from a single index family (Willmann 2014) plus a long-term HSCT follow-up of two patients (2025). Frequencies, penetrance, expressivity, survival, and QoL statistics cannot be reliably quantified.
2. No pathogenic variants in ClinVar. Diagnosis cannot rely on variant-database pathogenicity and requires functional kinase assays (F007), limiting routine clinical recognition.
3. Anti–type I IFN autoantibody link is inferred for NIK specifically. The predisposition is well-documented for CHUK/IKKα and RELB and is monitored in NIK patients, but direct, quantified human NIK-deficiency autoantibody data remain limited (F005).
4. Mouse–human divergence. Murine models capture lymphoid-architecture and B/T defects but may not fully model NK/Cryptosporidium susceptibility or autoantibody tolerance breakdown (F003).
5. No disease-specific OMIM number, ICD code, prevalence, or registry.
6. No modifier genes, epigenetic marks, or population-specific founder alleles identified.

Proposed Follow-up Experiments / Actions

1. Deposit functionally validated pathogenic MAP3K14 variants in ClinVar/ClinGen with ACMG/AMP evidence codes (PS3 functional) to enable future molecular diagnosis.
2. International case aggregation via GeneMatcher/IEI consortia to assemble a cohort large enough to estimate penetrance, phenotype spectrum, and survival.
3. Systematic anti–type I IFN autoantibody screening in all genetically confirmed NIK-deficiency patients to quantify the predisposition and its clinical impact (infection severity).
4. Standardized functional diagnostic assay (NIK kinase activity / p100→p52 processing in patient PBMCs or transfected constructs) validated for clinical laboratory use.
5. Pre-clinical gene-correction / thymic-regeneration studies in aly/aly mice to address the HSCT-refractory stromal/thymic architectural defect highlighted by the long-term follow-up (PMID: 41280889).
6. Single-cell transcriptomic profiling of patient lymphoid tissue/HSCT grafts to map the stromal vs hematopoietic contributions to residual immune dysfunction.
7. Natural-history / registry study (Orphanet-linked) to generate epidemiology, prognosis, and QoL data currently absent.

Report compiled from 8 confirmed findings and 34 reviewed papers over 5 completed investigation iterations. Evidence levels (human clinical / model organism / in vitro / computational) are flagged per finding. NIK deficiency is caused by biallelic loss-of-function mutations in MAP3K14 encoding NF-κB–inducing kinase (NIK).

Artifacts

• OpenScientist final report
• OpenScientist final report

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:

• MONDO:0018642 (2 mentions) - the report calls it "MONDO"; MONDO calls it NIK deficiency
• HP:0002718 (1 mention) - the report calls it "Clinical sign"; HP calls it Recurrent bacterial infections
• HP:0004429 (1 mention) - the report calls it "Clinical sign"; HP calls it Recurrent viral infections
• HP:0100792 (1 mention) - the report calls it "Clinical/laboratory"; HP calls it Acantholysis
• HP:0010976 (1 mention) - the report calls it "Laboratory abnormality"; HP calls it Decreased total B cell count
• HP:0002720 (1 mention) - the report calls it "Laboratory abnormality"; HP calls it Decreased circulating IgA concentration
• HP:0005404 (1 mention) - the report calls it "Laboratory abnormality"; HP calls it Increased total B cell count
• HP:0040218 (1 mention) - the report calls it "Laboratory abnormality"; HP calls it Reduced total natural killer cell count
• HP:0005415 (1 mention) - the report calls it "abnormal T-cell count"; HP calls it Decreased total CD8+ T cell proportion

Obsolete terms

These terms are real but deprecated. Citing one is not a fabrication; it does mean the report is naming something the ontology has retired:

• GO:0004704 (obsolete NF-kappaB-inducing kinase activity) (1 mention)
• GO:0051092 (obsolete positive regulation of NF-kappaB transcription factor activity) (1 mention)

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:

• UBERON:0001211 (1 mention) - the report calls it "Peyer's patches / gut-associated lymphoid tissue"; UBERON calls it Peyer's patch, and lists "aggregated lymphoid nodule" among its other names