Is HRAS p.Asp33= (c.99C>T) pathogenic?

HRAS p.Asp33= (c.99C>T) is classified Likely benign in HRAS (ClinVar, Single submitter, 1 submitter; last evaluated 2021-06-02). Very rare (popmax 0.00446%, eas); Associated with Costello syndrome.

What condition is associated with HRAS p.Asp33= (c.99C>T)?

HRAS p.Asp33= (c.99C>T) is associated with Costello syndrome (ClinVar).

How common is HRAS p.Asp33= (c.99C>T) in the general population?

HRAS p.Asp33= (c.99C>T) is very rare (popmax 0.00446%, eas) (gnomAD).

HRAS p.Asp33=

c.99C>T · rs756934316 · VCV1093653

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00446%, eas)

Conditions

Costello syndrome

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 1.4	GERP -3.7, phastCons 1
Overall
CADD	7.478	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00446% East Asian · 2/44,874 alleles

Filtering AF 0.000739% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000276%

Overall 0.000137% 2/1,460,002 alleles · very rare

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: HRAS
Protein: p.Asp33=
Coding: c.99C>T
MANE Select: NM_005343
dbSNP: rs756934316
Type: single nucleotide variant
Location: chr11:534224 (GRCh38)
Gene constraint: LOEUF 0.893 · pLI 0.02 · ClinGen HI 0/3 (gnomAD)
Structure: AlphaFold pLDDT 92.50 · 256 PDB
Residue 33: an α-helix; a binding site

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

Disease context

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

Similar variants

HRAS p.Asp33Tyr Uncertain significance ★★ ⚠ same residue
HRAS p.Asp33Asn Uncertain significance ★ ⚠ same residue
HRAS p.Asp33Glu Uncertain significance ★ ⚠ same residue
HRAS p.Ala59Thr Likely pathogenic ★★★ same condition
HRAS p.Gly12Ser Pathogenic ★★★ same condition
HRAS p.Gly13Cys Pathogenic ★★★ same condition
HRAS p.Lys117Arg Pathogenic ★★★ same condition
HRAS p.Thr58Ile 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/hras-p-asp33 (accessed [today's date]).

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