Is CDKN1C p.Pro126Leu (c.377C>T) pathogenic?

CDKN1C p.Pro126Leu (c.377C>T) is classified Uncertain significance in CDKN1C (ClinVar, Multiple submitters, 4 submitters; last evaluated 2026-01-02). AlphaMissense: likely benign (0.1514); Very rare (popmax 0.0044%, nfe); Associated with Beckwith-Wiedemann syndrome.

What condition is associated with CDKN1C p.Pro126Leu (c.377C>T)?

CDKN1C p.Pro126Leu (c.377C>T) is associated with Beckwith-Wiedemann syndrome, IMAGe syndrome (ClinVar).

How common is CDKN1C p.Pro126Leu (c.377C>T) in the general population?

CDKN1C p.Pro126Leu (c.377C>T) is very rare (popmax 0.0044%, nfe) (gnomAD).

What do computational predictors say about CDKN1C p.Pro126Leu (c.377C>T)?

AlphaMissense predicts likely benign (score 0.1514) — an in-silico prediction, not a clinical call.

CDKN1C p.Pro126Leu

c.377C>T · rs1445830484 · VCV575309

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 4 submitters

AlphaMissense

likely benign

0.1514 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.0044%, nfe)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Beckwith-Wiedemann syndrome

Computational evidence

Protein change
AlphaMissense	0.1514	likely benign
REVEL	0.038	moderately benign-leaning
SaProt	LLR -7.59	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 3.1	GERP 0.77, phastCons 0.26
Overall
CADD	19.5	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 P137L vs ClinVar P126L) — verify the residue.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0044% European (non-Finnish) · 48/1,091,270 alleles

Filtering AF 0.00341% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00301%

Overall 0.00342% 48/1,404,936 alleles · very rare

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: CDKN1C
Protein: p.Pro126Leu
Coding: c.377C>T
MANE Select: NM_001122630
dbSNP: rs1445830484
Type: single nucleotide variant
Location: chr11:2885080 (GRCh38)
Gene constraint: LOEUF 1.943 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 63.93
Residue 126: the 'disordered' region

Full CDKN1C gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Beckwith-Wiedemann syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: IMAGe syndrome

Similar variants

CDKN1C p.Pro126Ala Uncertain significance ★ ⚠ same residue
CDKN1C p.Arg268Ser Likely pathogenic ★★ same condition
CDKN1C p.Asp263Asn Pathogenic ★★ ⚠ same condition
CDKN1C p.Cys19Ter Pathogenic/Likely pathogenic ★★ same condition
CDKN1C p.Gln219Ter Pathogenic ★★ same condition
CDKN1C p.Gln221Ter Pathogenic ★★ same condition
CDKN1C p.Gln230Ter Pathogenic ★★ same condition
CDKN1C p.Glu119Ter 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/cdkn1c-p-pro126leu (accessed [today's date]).

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