GJB2 Gap junction protein beta 2 P29033 CXB2_HUMAN
Protein Coding Chr 13 13q12.11 Swiss-Prot reviewed Entrez 2706
Mutations
274
CL 42 · Tissue 228
Samples
137
CL 26 · Tissue 109
Peptides
89
unique mutant peptides
Transcripts
2
isoforms mutated

Stats by Source

Global, split by cell line (COSMIC CL / DepMap / PubMed) vs tissue (COSMIC primary tissue)

How the counts split by source
Stats by Source

Global = all mutations for this gene across every source.

Cell line = COSMIC Cell Lines Project + DepMap + PubMed.

Tissue = COSMIC primary-tissue (patient tumour) samples.

Global can exceed cell line + tissue: COSMIC tissue-derived models sit only in global, and a peptide can be shared across both.

GlobalCell lineTissue
Mutations27442228
Samples13726109
Peptides891976

Function

GJB2 · Gap junction protein beta 2

This gene encodes a member of the gap junction protein family (gap junction beta 2) but is more commonly known as connexin 26. The gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels that facilitate the transfer of ions and small molecules between cells. Connexins form hexameric channels in the plasma membrane which regulate passage of ions and small molecules between the cell and its environment or, when joined with another cell, form a dodecameric intercellular gap junction channel. The connexin proteins are grouped into alpha, beta, and gamma subfamilies. Mutations in this gene are responsible for as much as 50% of pre-lingual, recessive deafness. [provided by RefSeq, Mar 2026].

Isoforms & Proteins

2 transcripts · UniProt mapping is sequence-verified (AA-safe)

About the isoform mapping
Isoforms & Proteins

Each Ensembl transcript (ENST) this gene is mutated on, with its matched UniProt accession.

The mapping is sequence-verified: the UniProt sequence is identical to the transcript translation, so amino-acid positions line up exactly. A * marks an unreviewed (TrEMBL) entry.

Counts are mutations and unique mutant peptides on each transcript.

TranscriptUniProtMutationsPeptides
ENST00000382848 P29033 143 89
ENST00000382844 P29033 131 84

Gene Properties

Type
Protein Coding
Chromosome
13
Cytoband
13q12.11
Entrez ID
Aliases
BAPSCX26DFNA3DFNA3ADFNB1DFNB1A

Recurrent Mutations

Top recurrent amino-acid changes along the protein · needle height = number of mutations

What this lollipop shows
Recurrent Mutations

A lollipop / needle plot – the standard way to show recurrent mutations along a protein (as used by cBioPortal and MutationMapper).

X-axis = amino-acid position in the protein.

Needle height & head size = how often that exact amino-acid change was observed (its recurrence). Tall/large heads are mutational hotspots.

The most recurrent changes are labelled; hover any needle for the change, position and counts.

Mutation Distribution

Where GJB2 is mutated · all tissues, split by cell line vs tissue

Mutation counts by tissue
Mutation Distribution

How many mutations in GJB2 were found in each tissue, across the whole database.

Each bar is a tissue (cell-line and tissue names are merged to the standard tissue), split into cell line and tissue (patient tumour) contributions.

This shows the cancer-context where this gene is recurrently altered.

GTEx Expression

Median TPM across 54 healthy tissues

GTEx Portal ↗
About the expression data
GTEx Expression

Median gene expression (TPM) in normal, non-cancer human tissues from the GTEx project.

Useful for judging tumour specificity – a strong neoantigen target ideally comes from a gene with low expression in healthy tissues.

Scroll or drag the mini-axis below the chart to browse all tissues.

Mutations

All 274 mutations in GJB2

About the mutation list
Mutations

Every mutation record for this gene, across all samples and sources.

The Sample column links to the cell line (cell-line samples) or the tissue type (tissue samples).

Use the Type / Source filters, the search box, and column sorting to explore; each CAN-IMMUNE ID opens the full mutation & peptide view.

IDSampleTranscriptAA Change CDSTypeSourcePeptide