DEFB1
Chr 8defensin beta 1
Also known as: BD1, DEFB-1, DEFB101, HBD1
The DEFB1 protein is an antimicrobial peptide that provides bactericidal activity and helps protect epithelial surfaces from microbial colonization, while also functioning as a ligand for chemokine receptor CCR6. Mutations in this gene have been implicated in cystic fibrosis pathogenesis, though the specific inheritance pattern and clinical manifestations of primary DEFB1 deficiency require further characterization. This gene shows moderate tolerance to loss-of-function variants (LOEUF 1.689), suggesting some functional redundancy in antimicrobial defense pathways.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Tolerant to missense variation
The highest-scoring mechanism for this gene is dominant-negative.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
148 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 101 | 0 | 101 |
Likely Pathogenic | 0 | 0 | 4 | 0 | 4 |
VUS | 0 | 21 | 11 | 0 | 32 |
Likely Benign | 0 | 1 | 1 | 0 | 2 |
Benign | 0 | 0 | 3 | 1 | 4 |
| Total | 0 | 22 | 120 | 1 | 143 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
DEFB1 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
External Resources
Links to major genomics databases and tools