Is C4B p.Arg831His (c.2492G>A) pathogenic?

C4B p.Arg831His (c.2492G>A) is classified Uncertain significance in C4B (ClinVar, Single submitter, 1 submitter; last evaluated 2025-10-02). AlphaMissense: likely benign (0.093); Very rare (popmax 0.00584%, afr).

How common is C4B p.Arg831His (c.2492G>A) in the general population?

C4B p.Arg831His (c.2492G>A) is very rare (popmax 0.00584%, afr) (gnomAD).

What do computational predictors say about C4B p.Arg831His (c.2492G>A)?

AlphaMissense predicts likely benign (score 0.093) — an in-silico prediction, not a clinical call.

C4B p.Arg831His

c.2492G>A · VCV4647291

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.093 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00584%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.093	likely benign
REVEL	0.051	moderately benign-leaning
SaProt	LLR -8.52	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.3	GERP -4, phastCons 0.99
Overall
CADD	16.59	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 0.00584% African / African-American · 4/68,464 alleles

Filtering AF 0.00196% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00112%

Overall 0.000737% 11/1,492,996 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00584%	17,116
Admixed American	0.00182%	55,074
Remaining individualsnot grpmax-eligible	0.0017%	58,888
European (non-Finnish)	0.000457%	218,729

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: C4B
Protein: p.Arg831His
Coding: c.2492G>A
MANE Select: NM_007293 · reported on NM_001002029
Type: single nucleotide variant
Location: chr6:32027022 (GRCh38)
Structure: AlphaFold pLDDT 83.56 · 12 PDB

Full C4B gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

C4B p.Arg831Cys Uncertain significance ★ ⚠ same residue
C4A c.2944+55T>C Benign/Likely benign ★★ same type
C4A p.Asp1073Gly Benign/Likely benign ★★ same type
C4A p.Pro1120Thr Likely benign ★★ same type
C4B p.Ser1176Asn Benign ★★ ⚠ same type
C4B p.Thr907Ala Benign/Likely benign ★★ same type
C4B c.3230+1G>A Likely pathogenic ★ same type
C4B c.3676+1G>A Likely pathogenic ★ 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/c4b-p-arg831his (accessed [today's date]).

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