TBX5

Chr 12AD

T-box transcription factor 5

Also known as: HOS

The protein functions as a transcription factor that regulates gene expression during heart development and limb pattern formation. Mutations cause Holt-Oram syndrome through an autosomal dominant inheritance pattern, a developmental disorder affecting the heart and upper limbs. The pathogenic mechanism involves loss of function of this essential developmental regulator.

OMIMResearchSummary from RefSeq, OMIM, UniProt, Mechanism
LOFmechanismADLOEUF 0.141 OMIM phenotype
Clinical SummaryTBX5
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Gene-Disease Validity (ClinGen)
Holt-Oram syndrome · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

LoF intolerant — likely haploinsufficient
LoF Constraint
0.14LOEUF
pLI 1.000
Z-score 4.35
OE 0.00 (0.000.14)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint
1.19Z-score
OE missense 0.80 (0.720.90)
234 obs / 291.4 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.00 (0.000.14)
00.351.4
Missense OE0.80 (0.720.90)
00.61.4
Synonymous OE1.40
01.21.6
LoF obs/exp: 0 / 22.1Missense obs/exp: 234 / 291.4Syn Z: -3.44
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveTBX5-related Holt-Oram syndromeLOFAD
DN
0.3495th %ile
GOF
0.2995th %ile
LOF
0.83top 5%

This gene has evidence for multiple mechanisms of pathogenicity (loss-of-function and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to loss-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

LOFprediction above median · 1 literature citation · LOEUF 0.14
GOF1 literature citation

Literature Evidence

GOFA gain-of-function TBX5 mutation is associated with atypical Holt-Oram syndrome and paroxysmal atrial fibrillationPMID:18451335
LOFModeling Human TBX5 Haploinsufficiency Predicts Regulatory Networks for Congenital Heart Disease.PMID:33321106

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

TBX5 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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