Is RB1 p.Arg661Pro (c.1982G>C) pathogenic?

RB1 p.Arg661Pro (c.1982G>C) is classified Conflicting classifications of pathogenicity in RB1 (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2024-05-20). AlphaMissense: likely pathogenic (0.9989); No allele count reported in gnomAD v4.1 (AN 1,613,718); Associated with retinoblastoma.

What condition is associated with RB1 p.Arg661Pro (c.1982G>C)?

RB1 p.Arg661Pro (c.1982G>C) is associated with retinoblastoma (ClinVar).

How common is RB1 p.Arg661Pro (c.1982G>C) in the general population?

RB1 p.Arg661Pro (c.1982G>C) is no allele count reported in gnomAD v4.1 (AN 1,613,718) (gnomAD).

How is Retinoblastoma inherited?

Typically Autosomal dominant, Not applicable (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about RB1 p.Arg661Pro (c.1982G>C)?

AlphaMissense predicts likely pathogenic (score 0.9989) — an in-silico prediction, not a clinical call.

RB1 p.Arg661Pro

c.1982G>C · rs750578651 · VCV2859984

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

AlphaMissense

likely pathogenic

0.9989 · ACMG-weighted

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,613,718)

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

retinoblastoma

Computational evidence

Protein change
AlphaMissense	0.9989	likely pathogenic · top 1% in RB1
REVEL	0.96	strongly pathogenic-leaning
SaProt	LLR -17.05	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 1.8, phastCons 1
Regional constraint	o/e 0.81	unconstrained · MANE · 156 kb · p 9.1e-08 · regional, not allelic
Overall
CADD	34.0	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

No allele count reported in gnomAD v4.1 (AN 1,613,718). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: RB1
Protein: p.Arg661Pro
Coding: c.1982G>C
MANE Select: NM_000321
dbSNP: rs750578651
Type: single nucleotide variant
Location: chr13:48459709 (GRCh38)
Gene constraint: LOEUF 0.239 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.03 · 19 PDB
Residue 661: an α-helix; the 'pocket; binds t and e1a' region; a UniProt-annotated variant site (in rb; mild form); the 'domain b' region

Full RB1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

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

For Retinoblastoma (Orphanet):

Inheritance: Autosomal dominant, Not applicable
Onset: Antenatal, Childhood, Infancy
Prevalence: <1 / 1 000 000 (Europe)

Similar variants

RB1 p.Arg661Trp Pathogenic ★★ same residue
RB1 p.Arg661Gln Uncertain significance ★★ ⚠ same residue
RB1 p.Arg661= Likely benign ★ same residue
RB1 c.1049+1G>A Pathogenic/Likely pathogenic ★★ same condition
RB1 c.1049+1G>T Pathogenic/Likely pathogenic ★★ same condition
RB1 c.1049+3A>G Pathogenic/Likely pathogenic ★★ same condition
RB1 c.1050-2A>G Pathogenic/Likely pathogenic ★★ same condition
RB1 c.1128-1G>A 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/rb1-p-arg661pro (accessed [today's date]).

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