Is CDKN2A p.Pro81Ala (c.241C>G) pathogenic?

CDKN2A p.Pro81Ala (c.241C>G) is classified Uncertain significance in CDKN2A (ClinVar, Single submitter, 1 submitter; last evaluated 2026-04-27). AlphaMissense: ambiguous (0.4524); Absent from gnomAD v4.1; Associated with hereditary neoplastic syndrome.

What condition is associated with CDKN2A p.Pro81Ala (c.241C>G)?

CDKN2A p.Pro81Ala (c.241C>G) is associated with hereditary neoplastic syndrome (ClinVar).

How common is CDKN2A p.Pro81Ala (c.241C>G) in the general population?

CDKN2A p.Pro81Ala (c.241C>G) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about CDKN2A p.Pro81Ala (c.241C>G)?

AlphaMissense predicts ambiguous (score 0.4524) — an in-silico prediction, not a clinical call.

CDKN2A p.Pro81Ala

c.241C>G · VCV4868648

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.4524 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
AlphaMissense	0.4524	ambiguous
REVEL	0.622	indeterminate
SaProt	LLR -8.64	tolerated
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 2, phastCons 1
Regional constraint	o/e 1.13	unconstrained · MANE · 6,595 bp · p 0.04 · regional, not allelic
Overall
CADD	25.2	PHRED · no single calibrated threshold — expert panels disagree

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

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: CDKN2A
Protein: p.Pro81Ala
Coding: c.241C>G
MANE Select: NM_000077
Type: single nucleotide variant
Location: chr9:21971118 (GRCh38)
Gene constraint: LOEUF 0.791 · pLI 0.62 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.02 · 5 PDB
Residue 81: an α-helix; a UniProt-annotated variant site (in some patients with melanoma; impairs the function); a UniProt-annotated variant site (in cmm2; loss of cdk4 binding); 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

Similar variants

CDKN2A p.Pro81Leu Likely pathogenic ★★ same residue
CDKN2A p.Pro81= Uncertain significance ★ same residue
CDKN2A p.Pro81Arg Conflicting classifications of pathogenicity ★ ⚠ same residue
CDKN2A p.Pro81Ser Conflicting classifications of pathogenicity ★ ⚠ same residue
CDKN2A p.Pro81Thr Uncertain significance ★ ⚠ same residue
CDKN2A p.Pro81fs Pathogenic ★★ same residue
CDKN2A c.150+2T>G Likely 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-pro81ala (accessed [today's date]).

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