Is CDKN2A p.Leu9Pro (c.26T>C) pathogenic?

CDKN2A p.Leu9Pro (c.26T>C) is classified Uncertain significance in CDKN2A (ClinVar, Multiple submitters, 2 submitters; last evaluated 2023-07-18). Very rare (popmax 8.5e-05%, nfe); Associated with familial melanoma.

What condition is associated with CDKN2A p.Leu9Pro (c.26T>C)?

CDKN2A p.Leu9Pro (c.26T>C) is associated with familial melanoma, hereditary neoplastic syndrome (ClinVar).

How common is CDKN2A p.Leu9Pro (c.26T>C) in the general population?

CDKN2A p.Leu9Pro (c.26T>C) is very rare (popmax 8.5e-05%, nfe) (gnomAD).

How is Familial melanoma inherited?

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

CDKN2A p.Leu9Pro

c.26T>C · rs876659353 · VCV231774

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

very rare (popmax 8.5e-05%, nfe)

Conditions

familial melanoma

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.589	indeterminate
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 3.2	GERP 1.5, phastCons 1
Overall
CADD	24.0	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 8.5e-05% European (non-Finnish) · 1/1,176,400 alleles

Overall 6.23e-05% 1/1,604,834 alleles · very rare exomes 1/1,452,624 · genomes 0/152,210 · joint denominator

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: CDKN2A
Protein: p.Leu9Pro
Coding: c.26T>C
MANE Select: NM_000077 · reported on NM_058195
dbSNP: rs876659353
Type: single nucleotide variant
Location: chr9:21994306 (GRCh38)
Gene constraint: LOEUF 0.791 · pLI 0.62 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.02 · 5 PDB
Residue 9: the 'interaction with cdk5rap3 and mdm2' region

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.Met9Arg Uncertain significance ★★ ⚠ same residue
CDKN2A p.Met9Leu Uncertain significance ★★ ⚠ same residue
CDKN2A p.Met9Val Uncertain significance ★★ ⚠ same residue
CDKN2A p.Met9Ile Conflicting classifications of pathogenicity ★ ⚠ same residue
CDKN2A p.Met9Lys Conflicting classifications of pathogenicity ★ ⚠ same residue
CDKN2A p.Leu9= Benign ★ same residue
CDKN2A c.150+1G>A Likely pathogenic ★★ same condition
CDKN2A c.150+2T>G 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-leu9pro (accessed [today's date]).

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