Is TRPM4 p.Ser255Phe (c.764C>T) pathogenic?

TRPM4 p.Ser255Phe (c.764C>T) is classified Uncertain significance in TRPM4 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2026-02-25). AlphaMissense: likely benign (0.1881); Very rare (popmax 0.00267%, afr); Associated with progressive familial heart block type IB.

What condition is associated with TRPM4 p.Ser255Phe (c.764C>T)?

TRPM4 p.Ser255Phe (c.764C>T) is associated with progressive familial heart block type IB (ClinVar).

How common is TRPM4 p.Ser255Phe (c.764C>T) in the general population?

TRPM4 p.Ser255Phe (c.764C>T) is very rare (popmax 0.00267%, afr) (gnomAD).

What do computational predictors say about TRPM4 p.Ser255Phe (c.764C>T)?

AlphaMissense predicts likely benign (score 0.1881) — an in-silico prediction, not a clinical call.

TRPM4 p.Ser255Phe

Q: How is Hereditary progressive cardiac conduction defect inherited?

Typically Autosomal dominant (Orphanet). A genetic counselor can assess individual risk for a family.

c.764C>T · rs371904942 · VCV2563501

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

AlphaMissense

likely benign

0.1881 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00267%, afr)

Missense predictors

1/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

progressive familial heart block type IB

Computational evidence

Protein change
AlphaMissense	0.1881	likely benign
REVEL	0.098	moderately benign-leaning
SaProt	LLR -10.90	damaging
⇒ SaProt calls this damaging; AlphaMissense and REVEL do not.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.4	phastCons 1
Regional constraint	o/e 1.00	unconstrained · MANE · 43 kb · p 0.93 · regional, not allelic
Overall
CADD	24.8	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00267% African / African-American · 2/74,784 alleles

Filtering AF 0.000444% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000166%

Overall 0.000187% 3/1,606,042 alleles · very rare exomes 2/1,454,056 · genomes 1/151,986 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00267%	37,392
South Asian	0.00111%	89,954

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: TRPM4
Protein: p.Ser255Phe
Coding: c.764C>T
MANE Select: NM_017636
dbSNP: rs371904942
Type: single nucleotide variant
Location: chr19:49168704 (GRCh38)
Gene constraint: LOEUF 1.084 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 78.51 · 42 PDB
Residue 255: an α-helix

Full TRPM4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

progressive familial heart block type IB — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Hereditary progressive cardiac conduction defect (Orphanet):

Inheritance: Autosomal dominant
Onset: Adult

Similar variants

TRPM4 p.Ile1040Thr Pathogenic/Likely pathogenic ★★ same condition
TRPM4 p.Ile376Thr Pathogenic/Likely pathogenic ★★ ⚠ same condition
TRPM4 c.1050+1G>A Uncertain significance ★★ same condition
TRPM4 c.1150+5A>T Uncertain significance ★★ same condition
TRPM4 c.1150+6A>G Uncertain significance ★★ same condition
TRPM4 c.1263+1G>A Uncertain significance ★★ same condition
TRPM4 c.1263+2T>G Uncertain significance ★★ same condition
TRPM4 c.1608+1G>C Uncertain significance ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/trpm4-p-ser255phe (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown