Is EP300 p.Pro880= (c.2640C>G) pathogenic?

EP300 p.Pro880= (c.2640C>G) is classified Likely benign in EP300 (ClinVar, Single submitter, 2 submitters; last evaluated 2024-12-23). Very rare (popmax 0.00134%, afr); Associated with Rubinstein-Taybi syndrome due to EP300 haploinsufficiency.

What condition is associated with EP300 p.Pro880= (c.2640C>G)?

EP300 p.Pro880= (c.2640C>G) is associated with Rubinstein-Taybi syndrome due to EP300 haploinsufficiency (ClinVar).

How common is EP300 p.Pro880= (c.2640C>G) in the general population?

EP300 p.Pro880= (c.2640C>G) is very rare (popmax 0.00134%, afr) (gnomAD).

EP300 p.Pro880=

c.2640C>G · rs769353664 · VCV3029139

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00134%, afr)

Conditions

Rubinstein-Taybi syndrome due to EP300 haploinsufficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP -3.6	GERP -5
Overall
CADD	1.686	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00134% African / African-American · 1/74,882 alleles

Filtering AF 7.9e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 5.4e-05%

Overall 0.00031% 5/1,613,920 alleles · very rare exomes 4/1,461,804 · genomes 1/152,116 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00134%	74,882
European (non-Finnish)	0.000339%	295,008

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: EP300
Protein: p.Pro880=
Coding: c.2640C>G
MANE Select: NM_001429
dbSNP: rs769353664
Type: single nucleotide variant
Location: chr22:41150021 (GRCh38)
Gene constraint: LOEUF 0.164 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 54.88 · 60 PDB
Residue 880: the 'disordered' region

Full EP300 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Rubinstein-Taybi syndrome due to EP300 haploinsufficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

EP300 p.Pro880Leu Uncertain significance ★ ⚠ same residue
EP300 c.1282+1G>A Pathogenic/Likely pathogenic ★★ same condition
EP300 c.3671+1G>A Pathogenic/Likely pathogenic ★★ same condition
EP300 c.3729-2A>G Pathogenic/Likely pathogenic ★★ same condition
EP300 c.3857A>G Pathogenic/Likely pathogenic ★★ same condition
EP300 p.Arg1055Ter Pathogenic ★★ same condition
EP300 p.Arg1312Ter Pathogenic ★★ same condition
EP300 p.Arg1356Ter Pathogenic ★★ 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/ep300-p-pro880 (accessed [today's date]).

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