TPM4

Chr 19AD

tropomyosin 4

Also known as: BDPLT25, HEL-S-108

The protein binds to actin filaments and regulates muscle contraction through calcium-dependent mechanisms, while also playing a role in platelet biogenesis and cytoskeletal stabilization in non-muscle cells. Mutations cause autosomal dominant bleeding disorder, platelet-type, 25, which affects platelet function and hemostasis. The gene shows moderate constraint against loss-of-function variants (LOEUF 0.509), suggesting some tolerance to protein-truncating mutations.

OMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismADLOEUF 0.511 OMIM phenotype
Clinical SummaryTPM4
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Gene-Disease Validity (ClinGen)
TPM4-related platelet disorder · ADModerate

Moderate evidence — consider for supplementary testing

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.22) despite low pLI — interpret in context.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint
0.51LOEUF
pLI 0.389
Z-score 3.05
OE 0.22 (0.110.51)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
0.95Z-score
OE missense 0.79 (0.680.91)
127 obs / 160.9 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.22 (0.110.51)
00.351.4
Missense OE0.79 (0.680.91)
00.61.4
Synonymous OE0.86
01.21.6
LoF obs/exp: 4 / 18.0Missense obs/exp: 127 / 160.9Syn Z: 0.89
DN
0.89top 5%
GOF
0.7028th %ile
LOF
0.2582th %ile

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

DNprediction above median
GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

TPM4 · 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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