Is AFF1 p.Ser403Asn (c.1208G>A) pathogenic?

AFF1 p.Ser403Asn (c.1208G>A) is classified Uncertain significance in AFF1 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-09-23). AlphaMissense: likely benign (0.0884); Very rare (popmax 0.00139%, afr).

How common is AFF1 p.Ser403Asn (c.1208G>A) in the general population?

AFF1 p.Ser403Asn (c.1208G>A) is very rare (popmax 0.00139%, afr) (gnomAD).

What do computational predictors say about AFF1 p.Ser403Asn (c.1208G>A)?

AlphaMissense predicts likely benign (score 0.0884) — an in-silico prediction, not a clinical call.

AFF1 p.Ser403Asn

c.1208G>A · rs1724344009 · VCV3092142

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.0884 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00139%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.0884	likely benign
REVEL	0.117	moderately benign-leaning
SaProt	LLR -7.86	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 0.9	GERP 0.37, phastCons 1
Regional constraint	o/e 1.07	unconstrained · MANE · 84 kb · p 0.031 · regional, not allelic
Overall
CADD	15.1	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.

⚠ Isoform check: AlphaMissense numbered on a different transcript (AM S396N vs ClinVar S403N) — verify the residue.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00139% African / African-American · 1/71,928 alleles

Overall 0.000128% 2/1,559,792 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00139%	71,928
European (non-Finnish)	8.67e-05%	1,153,892

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: AFF1
Protein: p.Ser403Asn
Coding: c.1208G>A
MANE Select: NM_001166693
dbSNP: rs1724344009
Type: single nucleotide variant
Location: chr4:87091809 (GRCh38)
Gene constraint: LOEUF 0.49 · pLI 0.95 (gnomAD)
Structure: AlphaFold pLDDT 53.06 · 1 PDB
Residue 403: the 'disordered' region

Full AFF1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

AFF1 c.1191+8C>T Benign/Likely benign ★★ same type
AFF1 p.Ala40= Benign ★★ same type
AFF1 p.Pro393= Benign ★★ same type
AFF1 p.Ser627Cys Likely benign ★★ ⚠ same type
AFF1 p.Thr426= Likely benign ★★ same type
AFF1 p.Val711Ile Benign ★★ same type
AFF1 p.Ala1047Val Uncertain significance ★ ⚠ same type
AFF1 p.Ala1103Thr Uncertain significance ★ ⚠ 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/aff1-p-ser403asn (accessed [today's date]).

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