BBS2

Chr 16AR

Bardet-Biedl syndrome 2

ENSG00000125124 UniProt: Q9BXC9 OMIM: 615981

The protein encoded by this gene is a component of the BBSome complex, which functions as a coat complex that sorts specific membrane proteins to primary cilia and is required for ciliogenesis and ciliary membrane extension. Mutations cause Bardet-Biedl syndrome, an autosomal recessive disorder characterized by severe pigmentary retinopathy, obesity, polydactyly, renal malformation, and cognitive disability, as well as retinitis pigmentosa. The gene shows minimal constraint against loss-of-function variants (pLI near zero, LOEUF >1), consistent with its recessive inheritance pattern where heterozygous carriers are typically unaffected.

OMIM ResearchSummary from RefSeq, OMIM, UniProt

The BBSome complex is thought to function as a coat complex required for sorting of specific membrane proteins to the primary cilia. The BBSome complex is required for ciliogenesis but is dispensable for centriolar satellite function. This ciliogenic function is mediated in part by the Rab8 GDP/GTP exchange factor, which localizes to the basal body and contacts the BBSome. Rab8(GTP) enters the primary cilium and promotes extension of the ciliary membrane. Firstly the BBSome associates with the ciliary membrane and binds to RAB3IP/Rabin8, the guanosyl exchange factor (GEF) for Rab8 and then the Rab8-GTP localizes to the cilium and promotes docking and fusion of carrier vesicles to the base of the ciliary membrane. The BBSome complex, together with the LTZL1, controls SMO ciliary trafficking and contributes to the sonic hedgehog (SHH) pathway regulation. Required for proper BBSome complex assembly and its ciliary localization

OMIM ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Bardet-Biedl syndrome 2MIM #615981

Retinitis pigmentosa 74MIM #616562

Clinical highlights

Gene-disease validity (ClinGen)

BBS2-related ciliopathy · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

1.07

LOEUF

LOF

Mechanism· G2P

Some data sources returned errors (1)

ncbi: Error: NCBI fetch failed: 429 https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi