Is CD55 p.Asn303Ser (c.908A>G) pathogenic?

CD55 p.Asn303Ser (c.908A>G) is classified Uncertain significance in CD55 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-09-10). AlphaMissense: likely benign (0.0755); Very rare (popmax 0.00267%, afr); Associated with Inborn genetic diseases.

What condition is associated with CD55 p.Asn303Ser (c.908A>G)?

CD55 p.Asn303Ser (c.908A>G) is associated with Inborn genetic diseases (ClinVar).

How common is CD55 p.Asn303Ser (c.908A>G) in the general population?

CD55 p.Asn303Ser (c.908A>G) is very rare (popmax 0.00267%, afr) (gnomAD).

What do computational predictors say about CD55 p.Asn303Ser (c.908A>G)?

AlphaMissense predicts likely benign (score 0.0755) — an in-silico prediction, not a clinical call.

CD55 p.Asn303Ser

c.908A>G · VCV4222959

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.0755 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00267%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

Inborn genetic diseases

Computational evidence

Protein change
AlphaMissense	0.0755	likely benign
REVEL	0.046	moderately benign-leaning
SaProt	LLR -5.97	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	Δ0.30	donor gain · deltas
Pangolin	Δ0.45	gain · loss 0.00 · agrees with SpliceAI · independent
Constraint at this position
Conservation	phyloP -1.6	GERP -0.95
Regional constraint	o/e 0.90	unconstrained · MANE · 33 kb · p 0.17 · regional, not allelic
Overall
CADD	14.02	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 0.00267% African / African-American · 2/74,892 alleles

Filtering AF 0.000443% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000166%

Overall 0.000248% 4/1,613,808 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00267%	37,446
Remaining individualsnot grpmax-eligible	0.0016%	62,476
European (non-Finnish)	8.48e-05%	1,179,871

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: CD55
Protein: p.Asn303Ser
Coding: c.908A>G
MANE Select: NM_000574
Type: single nucleotide variant
Location: chr1:207336747 (GRCh38)
Gene constraint: LOEUF 1.234 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 78.99 · 33 PDB
Residue 303: the 'disordered' region

Full CD55 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Inborn genetic diseases — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

CD55 p.Asn303Thr Uncertain significance ★ ⚠ same residue
CD55 p.Arg221Ser Uncertain significance ★★ ⚠ same condition
CD55 p.Asn171Ser Uncertain significance ★★ ⚠ same condition
CD55 p.Asn44Asp Uncertain significance ★★ ⚠ same condition
CD55 p.Glu273Gly Uncertain significance ★★ ⚠ same condition
CD55 p.His339Asn Uncertain significance ★★ ⚠ same condition
CD55 p.Leu374Val Uncertain significance ★★ ⚠ same condition
CD55 p.Met377Thr Uncertain significance ★★ ⚠ 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/cd55-p-asn303ser (accessed [today's date]).

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