HTR3B

Chr 11

5-hydroxytryptamine receptor 3B

Also known as: 5-HT3B

NCBI Gene: 9177 ENSG00000149305 UniProt: O95264 OMIM: 604654

The product of this gene belongs to the ligand-gated ion channel receptor superfamily. This gene encodes subunit B of the type 3 receptor for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone, and a mitogen. This receptor causes fast, depolarizing responses in neurons after activation. It is not functional as a homomeric complex, but a pentaheteromeric complex with subunit A (HTR3A) displays the full functional features of this receptor. [provided by RefSeq, Aug 2011]

OMIM Research

OMIM ResearchGenerating clinical summary…

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

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LOEUF

Multiple*

Mechanism· predicted

Some data sources returned errors (1)

gnomad: Error: gnomAD API error: 400

Population Genetics & Constraint

gnomAD

Constraint data not available from gnomAD.

Background carrier burden — how many people carry a rare variant somewhere in HTR3B?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 99

571 rare PASS variants

Rare truncating (LoF)

1 in 1,300

110 rare PASS variants

Rare synonymous (reference)

1 in 250

214 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for HTR3B. A background rate for each class, not the frequency of any particular variant; thin-coverage exons undercount.

By genetic ancestry · 9 gnomAD groups · rare = under 0.1% in that group

Group	People	Missense	Truncating
European (non-Finnish)	~556k	1 in 170	1 in 1,700
South Asian	~43k	1 in 100	1 in 1,200
Remaining (unassigned)	~30k	1 in 92	1 in 500
European (Finnish)	~27k	1 in 250	≈ 1 in 13,000
Admixed American	~22k	1 in 65	1 in 560
African / African American	~21k	1 in 76	1 in 510
East Asian	~20k	1 in 120	1 in 530
Ashkenazi Jewish	~13k	1 in 380	1 in 840
Middle Eastern	~2,884	1 in 83	≈ 1 in 2,900

Each group is summed over the variants that are rare in that group. Grey ≈ figures rest on fewer than five expected carriers — too few to distinguish groups. Differences mostly reflect how many people were sampled and how much variation each ancestry carries, not disease risk.