MYH8
Chr 17ADmyosin heavy chain 8
Also known as: DA7, MyHC-peri, MyHC-pn, gtMHC-F
The MYH8 protein is a myosin heavy chain that functions in skeletal muscle contraction and is predominantly expressed in fetal skeletal muscle. Mutations cause trismus-pseudocamptodactyly syndrome and Carney complex variant, both inherited in an autosomal dominant pattern. The gene shows very low constraint against loss-of-function variants (pLI near zero), suggesting the pathogenic variants likely affect muscle function through other mechanisms.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
The highest-scoring mechanism for this gene is dominant-negative.
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
500 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 8 | 0 | 8 |
Likely Pathogenic | 2 | 0 | 0 | 0 | 2 |
VUS | 14 | 294 | 29 | 20 | 357 |
Likely Benign | 1 | 14 | 25 | 22 | 62 |
Benign | 0 | 2 | 34 | 8 | 44 |
Conflicting | — | 24 | |||
| Total | 17 | 310 | 96 | 50 | 497 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
MYH8 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools