Is PMS2 p.Ser403= (c.1209C>T) pathogenic?

PMS2 p.Ser403= (c.1209C>T) is classified Benign/Likely benign in PMS2 (ClinVar, Multiple submitters, 9 submitters; last evaluated 2026-02-01). Ultra-rare (popmax 0.0484%, amr); Associated with Hereditary nonpolyposis colorectal neoplasms.

How common is PMS2 p.Ser403= (c.1209C>T) in the general population?

PMS2 p.Ser403= (c.1209C>T) is ultra-rare (popmax 0.0484%, amr) (gnomAD).

PMS2 p.Ser403=

Q: What condition is associated with PMS2 p.Ser403= (c.1209C>T)?

PMS2 p.Ser403= (c.1209C>T) is associated with Hereditary nonpolyposis colorectal neoplasms, Lynch syndrome, Lynch syndrome 4 (ClinVar).

c.1209C>T · rs147399413 · VCV186504

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 9 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0484%, amr)

Conditions

Hereditary nonpolyposis colorectal neoplasms

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 -3.5
Overall
CADD	0.141	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0484% Admixed American · 29/59,964 alleles

Filtering AF 0.0345% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0299%

Overall 0.00192% 31/1,613,546 alleles · ultra-rare exomes 29/1,461,462 · genomes 2/152,084 · joint denominator

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.0484%	2,068
Remaining individualsnot grpmax-eligible	0.0016%	62,464
European (non-Finnish)	8.48e-05%	1,179,688

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: PMS2
Protein: p.Ser403=
Coding: c.1209C>T
MANE Select: NM_000535
dbSNP: rs147399413
Type: single nucleotide variant
Location: chr7:5987556 (GRCh38)
Gene constraint: LOEUF 0.898 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 71.37 · 9 PDB
Residue 403: the 'disordered' region

Full PMS2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Hereditary nonpolyposis colorectal neoplasms — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: Lynch syndrome Lynch syndrome 4 hereditary neoplastic syndrome

Similar variants

PMS2 p.Ser403Tyr Uncertain significance ★★ ⚠ same residue
PMS2 p.Ser403Phe Uncertain significance ★ ⚠ same residue
PMS2 c.1144+2T>A Likely pathogenic ★★★ same condition
PMS2 c.163+2T>C Likely pathogenic ★★★ same condition
PMS2 c.164-2A>G Likely pathogenic ★★★ same condition
PMS2 c.2007-1G>A Likely pathogenic ★★★ same condition
PMS2 c.2174+1G>A Pathogenic ★★★ same condition
PMS2 c.251-2A>G Likely 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/pms2-p-ser403 (accessed [today's date]).

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