Is CD55 p.Cys267Ser (c.800G>C) pathogenic?

CD55 p.Cys267Ser (c.800G>C) is classified Pathogenic in CD55 (ClinVar, Single submitter, 2 submitters; last evaluated 2024-07-05). AlphaMissense: likely pathogenic (0.9991); Absent from gnomAD v4.1; Associated with protein-losing enteropathy.

What condition is associated with CD55 p.Cys267Ser (c.800G>C)?

CD55 p.Cys267Ser (c.800G>C) is associated with protein-losing enteropathy (ClinVar).

How common is CD55 p.Cys267Ser (c.800G>C) in the general population?

CD55 p.Cys267Ser (c.800G>C) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about CD55 p.Cys267Ser (c.800G>C)?

AlphaMissense predicts likely pathogenic (score 0.9991) — an in-silico prediction, not a clinical call.

CD55 p.Cys267Ser

Q: How is Complement hyperactivation-angiopathic thrombosis-protein-losing enteropathy syndrome inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

c.800G>C · rs1135402917 · VCV431762

Pathogenic Single submitter

Classification

Pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 2 submitters

AlphaMissense

likely pathogenic

0.9991 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

protein-losing enteropathy

Computational evidence

Protein change
AlphaMissense	0.9991	likely pathogenic ✓ concordant with ClinVar · top 1% in CD55
REVEL	0.727	pathogenic-leaning
SaProt	LLR -13.41	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 7.9	GERP 0.95, phastCons 1
Regional constraint	o/e 0.90	unconstrained · MANE · 33 kb · p 0.17 · regional, not allelic
Overall
CADD	23.1	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

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: CD55
Protein: p.Cys267Ser
Coding: c.800G>C
MANE Select: NM_000574
dbSNP: rs1135402917
Type: single nucleotide variant
Location: chr1:207331243 (GRCh38)
Gene constraint: LOEUF 1.234 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 78.99 · 33 PDB
Residue 267: a disulfide bond; a UniProt-annotated variant site (in chaple; increased complement activation); the sushi 4 domain; a β-strand

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

Disease context

protein-losing enteropathy — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Complement hyperactivation-angiopathic thrombosis-protein-losing enteropathy syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood, Infancy
Prevalence: <1 / 1 000 000 (Worldwide)

Similar variants

CD55 c.286+2T>G Likely pathogenic ★★ same condition
CD55 p.Glu50Ter Pathogenic/Likely pathogenic ★★ same condition
CD55 c.1081+1G>C Uncertain significance ★★ same condition
CD55 p.Arg357Cys Uncertain significance ★★ ⚠ same condition
CD55 p.Arg52Leu Benign/Likely benign ★★ ⚠ same condition
CD55 p.Ser199Leu Pathogenic ★ ⚠ same condition
CD55 p.Trp33Ter Pathogenic ★ same condition
CD55 p.Glu50Lys 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-cys267ser (accessed [today's date]).

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