Is A2M p.Pro259Ser (c.775C>T) pathogenic?

A2M p.Pro259Ser (c.775C>T) is classified Uncertain significance in A2M (ClinVar, Single submitter, 1 submitter; last evaluated 2025-05-28). AlphaMissense: likely benign (0.2646); Very rare (popmax 0.00667%, afr).

How common is A2M p.Pro259Ser (c.775C>T) in the general population?

A2M p.Pro259Ser (c.775C>T) is very rare (popmax 0.00667%, afr) (gnomAD).

What do computational predictors say about A2M p.Pro259Ser (c.775C>T)?

AlphaMissense predicts likely benign (score 0.2646) — an in-silico prediction, not a clinical call.

A2M p.Pro259Ser

c.775C>T · VCV4049672

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.2646 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00667%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.2646	likely benign
REVEL	0.289	benign-leaning
SaProt	LLR -8.78	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 5.9	GERP 3.7, phastCons 1
Regional constraint	o/e 0.84	unconstrained · MANE · 48 kb · p 4.5e-12 · regional, not allelic
Overall
CADD	22.4	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00667% African / African-American · 5/74,918 alleles

Filtering AF 0.00255% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00161%

Overall 0.000372% 6/1,613,798 alleles · very rare exomes 1/1,461,614 · genomes 5/152,184 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00667%	14,984
European (non-Finnish)	8.48e-05%	1,179,876

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: A2M
Protein: p.Pro259Ser
Coding: c.775C>T
MANE Select: NM_000014
Type: single nucleotide variant
Location: chr12:9107628 (GRCh38)
Gene constraint: LOEUF 0.765 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 81.61 · 13 PDB

Full A2M gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

A2M c.3756+4G>A Benign/Likely benign ★★ same type
A2M p.Ala844= Benign ★★ same type
A2M p.Asp277Asn Benign ★★ same type
A2M p.Ile1000Val Benign ★★ same type
A2M p.Pro261Leu Benign ★★ same type
A2M p.Tyr1152= Benign/Likely benign ★★ same type
A2M p.Val120= Likely benign ★★ same type
A2M p.Val129= Benign ★★ same type

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/a2m-p-pro259ser (accessed [today's date]).

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