IEMbase 0785: AICDA-related hyper-IgM type 2
Scope
| Field | Value |
|---|---|
| IEMbase ID | 785 |
| Nosology | 16.3.05.01 |
| Nosology code | IEM0005 |
| Gene | AICDA |
| External IDs | OMIM:605258; ORPHA:101089 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | No exact local target; reject Severe_Combined_Immunodeficiency.yaml ADA-deficiency candidate |
| Review date | 2026-07-11 |
IEMbase phenotype signal
IEMbase labels this autosomal recessive record as AICDA-related activation-induced cytidine deaminase deficiency, with alternate name immunodeficiency with hyper-IgM type 2 and abbreviation HIGM2. The phenotype signal includes recurrent bacterial infections, lymphoid hyperplasia, giant germinal centers in lymph nodes, impaired immunoglobulin class-switch recombination, low IgG, low IgA, low IgE, normal B-cell counts, and normal or increased IgM.
DisMech phenotype coverage
No exact DisMech target was found. Local immunodeficiency entries include hyper-IgM-like patterns and class-switch defects in other diseases, such as activated PI3K-delta syndrome, ataxia-telangiectasia, IKBKG-related disease, and common variable immunodeficiency. These are mechanistic or phenotypic neighbors, not AICDA deficiency.
Concordance and completeness
Judgement: true local gap.
The generated severe combined immunodeficiency ADA-deficiency candidate is a purine/immunodeficiency lexical neighbor, not a match for AICDA-dependent somatic hypermutation/class-switch recombination failure. The current local knowledge base lacks the AICDA gene, HIGM2 identity, giant germinal centers, and the characteristic immunoglobulin profile as a single disease.
Curation actions
- Keep IEMbase 0785 unmapped.
- Reject ADA-SCID and generic hyper-IgM-like immune phenotypes as exact coverage.
- Future curation should create an AICDA/HIGM2 entry if hyper-IgM class-switch defects are prioritized.