TOP3A p.Arg656=
c.1968G>A · VCV3702077
Likely benign
Single submitter
Classification
Likely benign
ClinVar
Review
Single submitter ★☆☆☆
ClinVar · 1 submitter
gnomAD v4.1
Rare
ultra-rare (popmax 0.0111%, eas)
Computational evidence
| Protein change | ||
| Missense predictors do not apply to this variant type; conservation carries the signal. | ||
| Splicing | ||
| SpliceAI | <0.2 | all four deltas below 0.2 · C>A here scores Δ0.53 · evaluated, not missing |
|---|---|---|
| Constraint at this position | ||
| Conservation | phyloP 0.42 | GERP 0.59, phastCons 0.047 |
| Overall | ||
| CADD | 8.485 | PHRED · no single calibrated threshold — expert panels disagree |
Population frequency
gnomAD v4.1 · exomes + genomes
Grpmax group
0.0111%
East Asian · 5/44,890 alleles
Filtering AF
0.00434%
ClinGen BA1/BS1 input
FAF95, joint · FAF99 0.00276%
Overall
0.00031%
5/1,614,164 alleles · ultra-rare
exomes 4/1,461,820 · genomes 1/152,344 · joint denominator
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.Arg656=
- Coding
- c.1968G>A
- MANE Select
- NM_004618
- Type
- single nucleotide variant
- Location
- chr17:18282751 (GRCh38)
- Gene constraint
- LOEUF 0.737 · pLI <0.01 (gnomAD)
- Structure
- AlphaFold pLDDT 84.14 · 2 PDB
- Residue 656
- a UniProt-annotated variant site (in peob5)
Similar variants
- 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
- TOP3A p.Arg341Lys 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-arg656 (accessed [today's date]).
Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown