Is CD33 p.Thr303Arg (c.908C>G) pathogenic?

CD33 p.Thr303Arg (c.908C>G) is classified Uncertain significance in CD33 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-04-11). AlphaMissense: likely benign (0.0742); Ultra-rare (popmax 0.0613%, afr).

How common is CD33 p.Thr303Arg (c.908C>G) in the general population?

CD33 p.Thr303Arg (c.908C>G) is ultra-rare (popmax 0.0613%, afr) (gnomAD).

What do computational predictors say about CD33 p.Thr303Arg (c.908C>G)?

AlphaMissense predicts likely benign (score 0.0742) — an in-silico prediction, not a clinical call.

CD33 p.Thr303Arg

c.908C>G · VCV3998223

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.0742 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0613%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.0742	likely benign
REVEL	0.004	strongly benign-leaning
SaProt	LLR -6.48	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	<0.2	all four deltas below 0.2 · C>T here scores Δ0.22 · evaluated, not missing
Constraint at this position
Conservation	phyloP -12	GERP -3
Regional constraint	o/e 0.91	unconstrained · MANE · 15 kb · p 0.052 · regional, not allelic
Overall
CADD	0.005	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0613% African / African-American · 46/75,048 alleles

Filtering AF 0.0471% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0422%

Overall 0.00316% 51/1,613,680 alleles · ultra-rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.0613%	1,631
Admixed American	0.00834%	11,994

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: CD33
Protein: p.Thr303Arg
Coding: c.908C>G
MANE Select: NM_001772
Type: single nucleotide variant
Location: chr19:51235660 (GRCh38)
Gene constraint: LOEUF 1.072 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 78.30 · 11 PDB
Residue 303: the 'disordered' region

Full CD33 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

CD33 p.Asp51Asn Uncertain significance ★★ ⚠ same type
CD33 c.924+295A>G Benign ★★ same type
CD33 c.924+296C>T Benign ★★ same type
CD33 c.924+2T>C Benign ★★ same type
CD33 c.924+469G>C Benign ★★ same type
CD33 c.*201G>C Benign ★★ same type
CD33 p.Ala14Val Benign ★★ ⚠ same type
CD33 p.Ala65Pro Benign ★★ ⚠ 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/cd33-p-thr303arg (accessed [today's date]).

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