RAG2

protein-coding

recombination activating 2

Gene summary

This gene encodes a protein that is involved in the initiation of V(D)J recombination during B and T cell development. This protein forms a complex with the product of the adjacent recombination activating gene 1, and this complex can form double-strand breaks by cleaving DNA at conserved recombination signal sequences. The recombination activating gene 1 component is thought to contain most of the catalytic activity, while the N-terminal of the recombination activating gene 2 component is thought to form a six-bladed propeller in the active core that serves as a binding scaffold for the tight association of the complex with DNA. A C-terminal plant homeodomain finger-like motif in this protein is necessary for interactions with chromatin components, specifically with histone H3 that is trimethylated at lysine 4. Mutations in this gene cause Omenn syndrome, a form of severe combined immunodeficiency associated with autoimmune-like symptoms. [provided by RefSeq, Jul 2008]

MANE transcript

NM_000536.4

Inheritance

AR

ClinVar variants

P:163U:247B:209

Top phenotype

Severe combined immunodeficienc, autosomal recessive, T cell-negative, B cell-negative, natural killer cell-positive; Omenn syndrome; Combined cellular and humoral immune defects with granulomas

gnomAD constraint

pLI —, LoF o/e 0.38

Max pathogenic AF

—

Genomic locus

chr11:36,575,574-36,598,279

External References & Databases

Transcript & Mutation Effects

hg38 • Region Span ~22.7 kb
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GenCC Phenotypes & Disease Associations

Curated gene-disease validity assertions and inheritance patterns

severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-positiveSTRONG

Inheritance Pattern: AR

Disease ID:MONDO:0011086

Submitter: Labcorp Genetics (formerly Invitae)

severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-positiveSUPPORTIVE

Inheritance Pattern: AR

Disease ID:MONDO:0011086

Submitter: Orphanet

Omenn syndromeSTRONG

Inheritance Pattern: AR

Disease ID:MONDO:0011338

Submitter: Genomics England PanelApp

recombinase activating gene 2 deficiencySTRONG

Inheritance Pattern: AR

Disease ID:MONDO:0000573

Submitter: PanelApp Australia

recombinase activating gene 2 deficiencyDEFINITIVE

Inheritance Pattern: AR

Disease ID:MONDO:0000573

Submitter: ClinGen

RAG2 was first reported in relation to autosomal recessive recombinase activating gene 2 deficiency in 1996 (Schwarz K, et al., 1996, PMID: 8810255). RAG2 encodes recombination-activating gene 2, which is involved in V(D)J recombination and with RAG1 introduces double-stranded breaks between recombination signal sequences and coding segments. In RAG2-deficient individuals, V(D)J recombination is blocked such that mature B and T cells are not produced, leading to T-B- SCID which typically presents in infancy with recurrent, persistent infections by opportunistic organisms. Biallelic loss of function variants as associated with a SCID presentation, while hypomorphic alleles may lead to Leaky SCID with the presence of some mature T-cells. Omenn Syndrome -- characterized by SCID associated with erythroderma, hepatosplenomegaly, lymphadenopathy, and alopecia -- is one presentation of Leaky SCID. SCID, Leaky SCID and Omenn Syndrome are considered a spectrum of a single disease, and per criteria outlined by the ClinGen Lumping and Splitting Working Group, we found no difference in molecular mechanism or inheritance pattern. Therefore, all of the disease entities have been lumped into one disease entity, RAG2 deficiency. Generally, heterozygous parents/carriers are clinically unaffected. Over 100 unique variants (e.g. missense, in-frame indel, nonsense, frameshift, and large deletion) have been reported in humans. Curated evidence supporting the gene-disease relationship includes 15 probands with RAG2 variants who have been reported in 5 publications (PMIDs: 8810255, 11133745, 19912631, 26186701, 12200379). This gene-disease relationship is also supported by experimental evidence, including its biochemical function in V(D)J recombination (PMID: 8521468), which is altered in cell lines expressing RAG2 variants (PMID: 12200379). Additionally, RAG2 interacts with RAG1 (PMID: 8777717) which causes a similar phenotype and RAG2 expression is generally restricted in lymphocytes (PMID: 25613900). Furthermore, animal models recapitulate the spectrum of disease with Omenn syndrome (PMID: 17476358) and T-B- SCID (PMID: 11547487) phenotypes. More evidence is available in the literature, but the maximum score for genetic and experimental evidence has been reached. In summary, RAG2 is definitively associated with autosomal recessive RAG2 deficiency. This has been repeatedly demonstrated in both the research and clinical diagnostic settings and has been upheld over time. This classification was approved by the ClinGen SCID/CID Working Group on 08/19/2021.

Omenn syndromeSUPPORTIVE

Inheritance Pattern: AR

Disease ID:MONDO:0011338

Submitter: Orphanet

recombinase activating gene 2 deficiencyDEFINITIVE

Inheritance Pattern: AR

Disease ID:MONDO:0000573

Submitter: Natera

Omenn syndromeDEFINITIVE

Inheritance Pattern: AR

Disease ID:MONDO:0011338

Submitter: G2P

Clinical Genomic Database (CGD)

Severe combined immunodeficienc, autosomal recessive, T cell-negative, B cell-negative, natural killer cell-positive; Omenn syndrome; Combined cellular and humoral immune defects with granulomasAR

Manifestation: Allergy/Immunology/Infectious; Dermatologic; Gastrointestinal

Intervention: Allergy/Immunology/Infectious

Rationale: Antiinfectious prophylaxis (though special consideration is necessary related to the use of live vaccines) and early and aggressive treatment of infections may be beneficial; HSCT has been reported

Refs: 9630231; 10226883; 16276422; 20128425; 18463379; 21624848; 21184155; 21625022Source: CGD (NHGRI)

ClinVar Associated Diseases & Phenotypes

Reported disease conditions connected to RAG2 variants in ClinVar

16 Conditions Cataloged
Severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-positiveTotal: 483
Combined immunodeficiency with skin granulomasTotal: 482
Histiocytic medullary reticulosisTotal: 187
Recombinase activating gene 2 deficiencyTotal: 79
not providedTotal: 61
Inborn genetic diseasesTotal: 52
Inborn error of immunityTotal: 35
not specifiedTotal: 33

ClinVar Variants & Pathogenicity by Type

Statistics based on transcript NM_000536.4. Only rare variants are included.

We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.

Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.

EffectPLPVUSLBBSum
synonymous
5
clinvar
193
clinvar
1
clinvar
199
missense
14
clinvar
66
clinvar
237
clinvar
12
clinvar
3
clinvar
332
nonsense
8
clinvar
21
clinvar
1
clinvar
30
start loss
1
clinvar
2
clinvar
3
frameshift
25
clinvar
28
clinvar
1
clinvar
54
splice donor/acceptor (+/-2bp)
1
clinvar
1
Total471162472054619

Highest pathogenic variant AF is 0.00019638478

Loading ClinVar variants...

Transcript Catalog

Annotated transcript isoforms across RefSeq and Ensembl databases

Showing 4 of 9 transcripts
Transcript IDSourceProtein IDCoding ExonsMANE Status
NM_000536.4RefSeqNP_000527.21MANE Select
ENST00000311485.8EnsemblENSP00000308620.41MANE Select
NM_001243785.2RefSeqNP_001230714.11Standard
NM_001243786.2RefSeqNP_001230715.11Standard

Model Organisms & Knockout Phenotypes

Observed phenotypic effects in mouse and zebrafish models

Gene / ModelOrganismObserved Phenotype
rag2Danio rerio

Structure: lymphocyte

Quality: decreased amount

abnormal

Gene Ontology (GO) Annotations & Pathways

Biological processes, molecular functions, cellular components and pathways

Pathways ConsensusPathDB

  • Primary immunodeficiency - Homo sapiens (human)
  • FoxO signaling pathway - Homo sapiens (human)
  • MAPK6-MAPK4 signaling
  • Signal Transduction
  • MAPK6/MAPK4 signaling

Biological Process

  • B cell lineage commitment
  • pre-B cell allelic exclusion
  • B cell homeostatic proliferation
  • T cell lineage commitment
  • chromatin organization

Molecular Function

  • DNA binding
  • chromatin binding
  • phosphatidylinositol-4,5-bisphosphate binding
  • phosphatidylinositol-3,4,5-trisphosphate binding
  • zinc ion binding

Cellular Component

  • nucleoplasm
  • DNA recombinase complex

gnomAD Constraint

Source: gnomAD

Gene type
protein_coding
Transcript type
protein_coding
Transcript
ENST00000311485
Coding exons
1
Length
22706
Individuals with no LoFs
125709
Homozygous LoFs
0
Heterozygous LoFs
38
Defined
125747
p
0.000151
Z-ScoreObservedExpectedObserved/ExpectedMutation RateTotal Possible
Missense0.1972572660.9660.00001323504
Missense (PolyPhen)134152.080.88112054
Synonymous0.2349092.90.9690.000004241007
Loss of Function2.10513.30.3776.71e-7201

Population LoF Frequency

PopulationCAFp-valueStatus
African0.000120.00012rare
Latino/Admixed American0.000170.00017rare
Ashkenazi Jewish00.0absent
East Asian0.0000540.000054rare
Finnish0.0000460.000046rare
European (Non-Finnish)0.000190.00019rare
South Asian0.000130.00013rare
Other0.000330.00033rare

dbNSFP Gene Annotations

Source: dbNSFP

Function
FUNCTION: Core component of the RAG complex, a multiprotein complex that mediates the DNA cleavage phase during V(D)J recombination. V(D)J recombination assembles a diverse repertoire of immunoglobulin and T-cell receptor genes in developing B and T- lymphocytes through rearrangement of different V (variable), in some cases D (diversity), and J (joining) gene segments. DNA cleavage by the RAG complex occurs in 2 steps: a first nick is introduced in the top strand immediately upstream of the heptamer, generating a 3'-hydroxyl group that can attack the phosphodiester bond on the opposite strand in a direct transesterification reaction, thereby creating 4 DNA ends: 2 hairpin coding ends and 2 blunt, 5'-phosphorylated ends. The chromatin structure plays an essential role in the V(D)J recombination reactions and the presence of histone H3 trimethylated at 'Lys-4' (H3K4me3) stimulates both the nicking and haipinning steps. The RAG complex also plays a role in pre-B cell allelic exclusion, a process leading to expression of a single immunoglobulin heavy chain allele to enforce clonality and monospecific recognition by the B- cell antigen receptor (BCR) expressed on individual B-lymphocytes. The introduction of DNA breaks by the RAG complex on one immunoglobulin allele induces ATM-dependent repositioning of the other allele to pericentromeric heterochromatin, preventing accessibility to the RAG complex and recombination of the second allele. In the RAG complex, RAG2 is not the catalytic component but is required for all known catalytic activities mediated by RAG1. It probably acts as a sensor of chromatin state that recruits the RAG complex to H3K4me3 (By similarity). {ECO:0000250}.;
Disease
DISEASE: Combined cellular and humoral immune defects with granulomas (CHIDG) [MIM:233650]: Immunodeficiency disease with granulomas in the skin, mucous membranes, and internal organs. Other characteristics include hypogammaglobulinemia, a diminished number of T and B-cells, and sparse thymic tissue on ultrasonography. {ECO:0000269|PubMed:18463379}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Severe combined immunodeficiency autosomal recessive T- cell-negative/B-cell-negative/NK-cell-positive (T(-)B(-)NK(+) SCID) [MIM:601457]: A form of severe combined immunodeficiency (SCID), a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. Patients present in infancy recurrent, persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development. {ECO:0000269|PubMed:8810255}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Omenn syndrome (OS) [MIM:603554]: Severe immunodeficiency characterized by the presence of activated, anergic, oligoclonal T-cells, hypereosinophilia, and high IgE levels. {ECO:0000269|PubMed:9630231}. Note=The disease is caused by mutations affecting the gene represented in this entry.;

Recessive Scores

pRec
0.607

Intolerance Scores

LoFtool
0.206
RVIS EVS
0.02
RVIS percentile EVS
55.61

Essentials

Essential (CRISPR)
N
Essential (CRISPR2)
N
Essential (gene trap)
N
Indispensability pred.
E
Indispensability score
0.935

Gene Damage Prediction

AllRecessiveDominant
MendelianMediumMediumMedium
Primary ImmunodeficiencyMediumMediumMedium
CancerMediumMediumMedium
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