Is CDKN2A p.Ala133Val (c.398C>T) pathogenic?

CDKN2A p.Ala133Val (c.398C>T) is classified Uncertain significance in CDKN2A (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-02-09). AlphaMissense: likely benign (0.1407); Absent from gnomAD v4.1; Associated with familial melanoma.

What condition is associated with CDKN2A p.Ala133Val (c.398C>T)?

CDKN2A p.Ala133Val (c.398C>T) is associated with familial melanoma, hereditary neoplastic syndrome (ClinVar).

How common is CDKN2A p.Ala133Val (c.398C>T) in the general population?

CDKN2A p.Ala133Val (c.398C>T) is absent from gnomAD v4.1 (gnomAD).

How is Familial melanoma inherited?

Typically Autosomal dominant, Multigenic/multifactorial (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about CDKN2A p.Ala133Val (c.398C>T)?

AlphaMissense predicts likely benign (score 0.1407) — an in-silico prediction, not a clinical call.

CDKN2A p.Ala133Val

c.398C>T · VCV3658067

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.1407 · ACMG-weighted

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,611,732)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

familial melanoma

Computational evidence

Protein change
AlphaMissense	0.1407	likely benign
REVEL	0.218	benign-leaning
SaProt	LLR -6.34	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 3.2	GERP -0.79, phastCons 0.99
Regional constraint	o/e 1.13	unconstrained · MANE · 6,595 bp · p 0.04 · regional, not allelic
Overall
CADD	14.38	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 1,611,732). 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.Ala133Val
Coding: c.398C>T
MANE Select: NM_000077
Type: single nucleotide variant
Location: chr9:21970961 (GRCh38)
Gene constraint: LOEUF 0.791 · pLI 0.62 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.02 · 5 PDB
Residue 133: an α-helix

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

Disease context

familial melanoma — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary neoplastic syndrome

For Familial melanoma (Orphanet):

Inheritance: Autosomal dominant, Multigenic/multifactorial
Onset: Adult
Prevalence: 1-9 / 100 000 (Europe)

Similar variants

CDKN2A p.Ala133Ser Uncertain significance ★★ ⚠ same residue
CDKN2A p.Ala133Thr Uncertain significance ★★ ⚠ same residue
CDKN2A p.Ala133fs 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
CDKN2A c.151-1G>T Pathogenic/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/cdkn2a-p-ala133val (accessed [today's date]).

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