Is CDKN2A p.Ala109Ser (c.325G>T) pathogenic?

CDKN2A p.Ala109Ser (c.325G>T) is classified Uncertain significance in CDKN2A (ClinVar, Multiple submitters, 3 submitters; last evaluated 2025-09-01). AlphaMissense: likely benign (0.1441); Absent from gnomAD v4.1; Associated with hereditary neoplastic syndrome.

What condition is associated with CDKN2A p.Ala109Ser (c.325G>T)?

CDKN2A p.Ala109Ser (c.325G>T) is associated with hereditary neoplastic syndrome, familial melanoma (ClinVar).

How common is CDKN2A p.Ala109Ser (c.325G>T) in the general population?

CDKN2A p.Ala109Ser (c.325G>T) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about CDKN2A p.Ala109Ser (c.325G>T)?

AlphaMissense predicts likely benign (score 0.1441) — an in-silico prediction, not a clinical call.

CDKN2A p.Ala109Ser

c.325G>T · rs372481694 · VCV628079

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

AlphaMissense

likely benign

0.1441 · ACMG-weighted

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,606,374)

Missense predictors

0/2 damaging

AlphaMissense, SaProt · REVEL no call

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
AlphaMissense	0.1441	likely benign
REVEL	0.427	indeterminate
SaProt	LLR -7.66	tolerated
⇒ AlphaMissense and SaProt both call this tolerated; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 0.78	GERP 1, phastCons 0.2
Regional constraint	o/e 1.13	unconstrained · MANE · 6,595 bp · p 0.04 · regional, not allelic
Overall
CADD	17.2	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

No allele count reported in gnomAD v4.1 (AN 1,606,374). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: CDKN2A
Protein: p.Ala109Ser
Coding: c.325G>T
MANE Select: NM_000077
dbSNP: rs372481694
Type: single nucleotide variant
Location: chr9:21971034 (GRCh38)
Gene constraint: LOEUF 0.791 · pLI 0.62 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.02 · 5 PDB
Residue 109: a β-strand; the 'disordered' region

Full CDKN2A gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hereditary neoplastic syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: familial melanoma

Similar variants

CDKN2A p.Ala109Asp Uncertain significance ★★ ⚠ same residue
CDKN2A p.Ala109Pro Uncertain significance ★★ ⚠ same residue
CDKN2A p.Ala109= Likely benign ★★ same residue
CDKN2A p.Ala109Thr Uncertain significance ★ ⚠ same residue
CDKN2A c.150+1G>A Likely pathogenic ★★ same condition
CDKN2A c.150+2T>G Likely pathogenic ★★ same condition
CDKN2A c.151-1G>A Pathogenic ★★ same condition
CDKN2A c.151-1G>C 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/cdkn2a-p-ala109ser (accessed [today's date]).

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