Previous symbols: BBS.
BBS2 is a core scaffolding subunit of the BBSome, a stable octameric, coat-like adaptor complex (BBS1, BBS2, BBS4, BBS5, BBS7, BBS8/TTC8, BBS9 and BBIP1/BBIP10) that traffics specific membrane proteins, especially signaling receptors such as ciliary G-protein-coupled receptors and Hedgehog-pathway components (e.g. Smoothened), into and out of the primary cilium. BBS2 is a ~721-residue protein built from a coatomer/adaptin-like architecture: an N-terminal beta-propeller, followed by middle, GAE (gamma-adaptin ear), platform and C-terminal helical domains, plus a coiled-coil region; together with BBS7 and BBS9 it forms the beta-propeller/GAE/platform scaffold core of the complex. The BBSome is recruited to the ciliary membrane by the small GTPase ARL6/BBS3-GTP and cooperates with the Rab8 GEF Rabin8 (RAB3IP) and Rab8 to promote ciliary membrane biogenesis and cargo sorting; LZTFL1 regulates its ciliary entry. BBSome-mediated trafficking is required for proper localization and signaling of receptors including the leptin receptor, linking BBS2 to energy homeostasis. BBS2 itself has no catalytic activity; it acts as a structural/adaptor module. The protein localizes to the ciliary membrane, basal body, ciliary transition zone, centriolar satellites and the cytoplasm. Loss-of-function mutations cause autosomal-recessive Bardet-Biedl syndrome (retinal degeneration, obesity, polydactyly, renal anomalies, hypogenitalism, cognitive impairment) and, for certain missense alleles, nonsyndromic retinitis pigmentosa.
Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.
| Disorder | Relationship | Where the gene appears |
|---|---|---|
| Bardet-Biedl syndrome |
untyped
Pathogenic biallelic variants
|
mechanism: BBSome subunit deficiency; Pathogenic BBS gene defects
|
| BBSome-related retinitis pigmentosa |
untyped
Pathogenic biallelic variants, especially reported missense combinations
|
mechanism: Partial or retina-selective BBSome dysfunction
subtype: RP74
scoped to subtype: RP74
|
An entry matches when ClinGen's MONDO disease is the entry's own disease term, a subtype term, or an exact-match mapping. An amber status marks an entry ClinGen supports the gene for (Definitive, Strong or Moderate) whose own record does not type it. A Limited, Disputed or Refuted tier on such an entry is not a gap.
| ClinGen disease | MOI | Classification | dismech entry |
|---|---|---|---|
| BBS2-related ciliopathy MONDO:1040048 | AR | Definitive 2024-03-07 |
no dismech entry |
Identity from HGNC (snapshot 2026-10-01). Page layers are described in the gene pages documentation.