GNAS p.Ile26=
c.78C>T · rs996154956 · VCV1912681
Likely benign
Single submitter
Classification
Likely benign
ClinVar
Review
Single submitter ★☆☆☆
ClinVar · 2 submitters
gnomAD v4.1
Rare
very rare (popmax 0.00249%, sas)
Computational evidence
| Protein change | ||
| Missense predictors do not apply to this variant type; conservation carries the signal. | ||
| Splicing | ||
| SpliceAI | — | not assessed · no allele here is in the release |
|---|---|---|
| Constraint at this position | ||
| Conservation | phyloP 3.7 | GERP -3.7, phastCons 1 |
| Overall | ||
| CADD | 14.94 | PHRED · no single calibrated threshold — expert panels disagree |
Population frequency
gnomAD v4.1 · exomes + genomes
Grpmax group
0.00249%
South Asian · 2/80,378 alleles
Filtering AF
0.000413%
ClinGen BA1/BS1 input
FAF95, joint · FAF99 0.000254%
Overall
0.000854%
11/1,288,212 alleles · very rare
exomes 10/1,141,868 · genomes 1/146,344 · joint denominator
| Ancestry group | Frequency | 1 in |
|---|---|---|
| South Asiangrpmax | 0.00249% | 40,189 |
| African / African-American | 0.00158% | 63,186 |
| European (non-Finnish) | 0.000818% | 122,248 |
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
- GNAS
- Protein
- p.Ile26=
- Coding
- c.78C>T
- MANE Select
- NM_000516
- dbSNP
- rs996154956
- Type
- single nucleotide variant
- Location
- chr20:58891804 (GRCh38)
- Gene constraint
- LOEUF 0.302 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
- Structure
- AlphaFold pLDDT 59.47 · 200 PDB
- Residue 26
- an α-helix; the 'disordered' region
Similar variants
- GNAS p.Pro26= Likely benign same residue
- GNAS p.Ile26fs Pathogenic ★ same residue
- GNAS c.139+1G>C Pathogenic ★★ same type
- GNAS c.139+2T>C Pathogenic ★★ same type
- GNAS c.312+5G>A Pathogenic ★★ same type
- GNAS c.432+1G>A Pathogenic ★★ same type
- GNAS c.433-2A>C Pathogenic/Likely pathogenic ★★ same type
- GNAS p.Ala102Thr Pathogenic/Likely pathogenic ★★ same type
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/gnas-p-ile26 (accessed [today's date]).
Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown