SFTPB
Chr 2ARsurfactant protein B
Also known as: PSP-B, SFTB3, SFTP3, SMDP1, SP-B
Surfactant protein B is an amphipathic protein that reduces surface tension at the air-liquid interface in alveoli and enhances the spreading and stability of pulmonary surfactant monolayers essential for lung function after birth. Mutations cause surfactant metabolism dysfunction type 1 (pulmonary alveolar proteinosis due to surfactant protein B deficiency), which presents with fatal respiratory distress in the neonatal period. This condition follows autosomal recessive inheritance.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.
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
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
SFTPB · 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
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools