AP3B1
Chr 5ARadaptor related protein complex 3 subunit beta 1
Also known as: ADTB3, ADTB3A, HPS, HPS2, PE
The AP3B1 protein is a subunit of the adaptor protein complex 3 (AP-3) that sorts transmembrane proteins to lysosomes and lysosome-related organelles including melanosomes and platelet dense granules. Mutations cause Hermansky-Pudlak syndrome type 2, an autosomal recessive disorder characterized by oculocutaneous albinism, bleeding diathesis due to platelet storage pool deficiency, and variable pulmonary fibrosis. The gene shows significant constraint against loss-of-function variants (LOEUF 0.344), reflecting its essential cellular function.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly LoF-intolerant (top ~10% of genes)
Mild missense constraint
ClinVar Variant Classifications
500 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 | 22 | 0 | 4 | 0 | 26 |
Likely Pathogenic | 29 | 1 | 0 | 0 | 30 |
VUS | 3 | 186 | 9 | 0 | 198 |
Likely Benign | 0 | 2 | 107 | 117 | 226 |
Benign | 0 | 0 | 1 | 0 | 1 |
| Total | 54 | 189 | 121 | 117 | 481 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
AP3B1 · 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