Is ERCC4 p.Arg9Pro (c.26G>C) pathogenic?

ERCC4 p.Arg9Pro (c.26G>C) is classified Uncertain significance in ERCC4 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-08-10). AlphaMissense: likely benign (0.072); Very rare (popmax 0.00223%, eas); Associated with Cockayne syndrome.

What condition is associated with ERCC4 p.Arg9Pro (c.26G>C)?

ERCC4 p.Arg9Pro (c.26G>C) is associated with Cockayne syndrome, xeroderma pigmentosum group F, Fanconi anemia complementation group Q (ClinVar).

How common is ERCC4 p.Arg9Pro (c.26G>C) in the general population?

ERCC4 p.Arg9Pro (c.26G>C) is very rare (popmax 0.00223%, eas) (gnomAD).

How is Cockayne syndrome inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about ERCC4 p.Arg9Pro (c.26G>C)?

AlphaMissense predicts likely benign (score 0.072) — an in-silico prediction, not a clinical call.

ERCC4 p.Arg9Pro

c.26G>C · rs1214498950 · VCV854210

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.072 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Cockayne syndrome

Computational evidence

Protein change
AlphaMissense	0.072	likely benign
REVEL	0.031	moderately benign-leaning
SaProt	LLR -6.14	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 -1.9	GERP -3.7
Regional constraint	o/e 1.08	unconstrained · MANE · 28 kb · p 0.011 · regional, not allelic
Overall
CADD	0.056	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

Grpmax group 0.00223% East Asian · 1/44,884 alleles

Overall 6.88e-05% 1/1,454,226 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: ERCC4
Protein: p.Arg9Pro
Coding: c.26G>C
MANE Select: NM_005236
dbSNP: rs1214498950
Type: single nucleotide variant
Location: chr16:13920191 (GRCh38)
Gene constraint: LOEUF 0.984 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 74.60 · 13 PDB
Residue 9: the 'helicase-like' region

Full ERCC4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

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

Also linked: xeroderma pigmentosum group F Fanconi anemia complementation group Q

For Cockayne syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages
Prevalence: 1-9 / 1 000 000 (Europe)

Similar variants

ERCC4 p.Arg9Gly Uncertain significance ★★ ⚠ same residue
ERCC4 c.1102+1G>T Likely pathogenic ★★ same condition
ERCC4 c.793-2A>G Pathogenic ★★ same condition
ERCC4 p.Arg20Ter Pathogenic ★★ same condition
ERCC4 p.Arg589Trp Pathogenic/Likely pathogenic ★★ same condition
ERCC4 p.Arg689Ser Likely pathogenic ★★ same condition
ERCC4 p.Arg772Ter Pathogenic/Likely pathogenic ★★ same condition
ERCC4 p.Cys236Arg 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/ercc4-p-arg9pro (accessed [today's date]).

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