Is RNF43 p.Ala129= (c.387G>A) pathogenic?

RNF43 p.Ala129= (c.387G>A) is classified Benign/Likely benign in RNF43 (ClinVar, Multiple submitters, 4 submitters; last evaluated 2025-12-29). Very rare (popmax 0.00893%, eas); Associated with sessile serrated polyposis cancer syndrome.

What condition is associated with RNF43 p.Ala129= (c.387G>A)?

RNF43 p.Ala129= (c.387G>A) is associated with sessile serrated polyposis cancer syndrome (ClinVar).

How common is RNF43 p.Ala129= (c.387G>A) in the general population?

RNF43 p.Ala129= (c.387G>A) is very rare (popmax 0.00893%, eas) (gnomAD).

How is Serrated polyposis syndrome inherited?

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

RNF43 p.Ala129=

c.387G>A · rs755845342 · VCV933634

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 4 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00893%, eas)

Conditions

sessile serrated polyposis cancer syndrome

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP -13	GERP -4.2
Overall
CADD	0.704	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00893% East Asian · 4/44,784 alleles

Filtering AF 0.00348% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00229%

Overall 0.0018% 29/1,611,222 alleles · very rare exomes 25/1,459,164 · genomes 4/152,058 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00893%	11,196
African / African-American	0.00802%	12,469
South Asian	0.0022%	45,448
Remaining individualsnot grpmax-eligible	0.0016%	62,334
European (non-Finnish)	0.00136%	73,632

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: RNF43
Protein: p.Ala129=
Coding: c.387G>A
MANE Select: NM_017763
dbSNP: rs755845342
Type: single nucleotide variant
Location: chr17:58363589 (GRCh38)
Gene constraint: LOEUF 0.632 · pLI <0.01 · ClinGen HI 2/3 (gnomAD)
Structure: AlphaFold pLDDT 55.86 · 2 PDB
Residue 129: an α-helix

Full RNF43 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

sessile serrated polyposis cancer syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Serrated polyposis syndrome (Orphanet):

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

Similar variants

RNF43 p.Ala129Val Uncertain significance ★ ⚠ same residue
RNF43 p.Arg337Ter Pathogenic/Likely pathogenic ★★ same condition
RNF43 c.688-3C>T Uncertain significance ★★ same condition
RNF43 p.Ala115Val Uncertain significance ★★ ⚠ same condition
RNF43 p.Ala126Val Uncertain significance ★★ ⚠ same condition
RNF43 p.Ala148Gly Uncertain significance ★★ ⚠ same condition
RNF43 p.Ala169Ser Uncertain significance ★★ ⚠ same condition
RNF43 p.Ala193Val Uncertain significance ★★ ⚠ 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/rnf43-p-ala129 (accessed [today's date]).

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