TOP3A p.Ile280=
c.840C>T · VCV3605568
Likely benign
Single submitter
Classification
Likely benign
ClinVar
Review
Single submitter ★☆☆☆
ClinVar · 1 submitter
gnomAD v4.1
Rare
very rare (popmax 0.00659%, sas)
Computational evidence
| Protein change | ||
| Missense predictors do not apply to this variant type; conservation carries the signal. | ||
| REVEL | 0.11 | moderately benign-leaning |
|---|---|---|
| Splicing | ||
| SpliceAI | — | not assessed · no allele here is in the release |
| Constraint at this position | ||
| Conservation | phyloP -5.1 | GERP -3.6 |
| Overall | ||
| CADD | 2.342 | PHRED · no single calibrated threshold — expert panels disagree |
Population frequency
gnomAD v4.1 · exomes + genomes
Grpmax group
0.00659%
South Asian · 6/91,080 alleles
Filtering AF
0.00286%
ClinGen BA1/BS1 input
FAF95, joint · FAF99 0.00195%
Overall
0.000682%
11/1,613,982 alleles · very rare
exomes 9/1,461,812 · genomes 2/152,170 · joint denominator
| Ancestry group | Frequency | 1 in |
|---|---|---|
| South Asiangrpmax | 0.00659% | 15,180 |
| Admixed American | 0.00333% | 29,993 |
| East Asian | 0.00223% | 44,902 |
| Remaining individualsnot grpmax-eligible | 0.0016% | 62,490 |
| European (non-Finnish) | 8.47e-05% | 1,179,997 |
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
- TOP3A
- Protein
- p.Ile280=
- Coding
- c.840C>T
- MANE Select
- NM_004618
- Type
- single nucleotide variant
- Location
- chr17:18301960 (GRCh38)
- Gene constraint
- LOEUF 0.737 · pLI <0.01 (gnomAD)
- Structure
- AlphaFold pLDDT 84.14 · 2 PDB
- Residue 280
- the topo ia-type catalytic domain; a UniProt-annotated variant site (in peob5); a β-strand
Similar variants
- TOP3A p.Ile280Met Likely benign ★★ same residue
- TOP3A c.990+1G>T Likely pathogenic ★★ same type
- TOP3A p.Arg135Ter Pathogenic/Likely pathogenic ★★ same type
- TOP3A p.Arg177Ter Pathogenic/Likely pathogenic ★★ same type
- TOP3A p.Arg338Ter Pathogenic/Likely pathogenic ★★ same type
- TOP3A p.Ala622Thr Uncertain significance ★★ ⚠ same type
- TOP3A p.Ala642Val Uncertain significance ★★ ⚠ same type
- TOP3A p.Ala941Thr Uncertain significance ★★ ⚠ 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/top3a-p-ile280 (accessed [today's date]).
Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown