Is C5 c.421+2T>C pathogenic?

C5 c.421+2T>C is classified Likely pathogenic in C5 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-01-17). Very rare (popmax 0.00167%, amr).

How common is C5 c.421+2T>C in the general population?

C5 c.421+2T>C is very rare (popmax 0.00167%, amr) (gnomAD).

C5 c.421+2T>C

rs746623019 · VCV3010225

Likely pathogenic Single submitter

Classification

Likely pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

canonical splice-site (±1/±2)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 0.00167%, amr)

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation/SpliceAI carries the signal.
Consequence	canonical splice-site (±1/±2)	predicted loss-of-function
Splicing
Splice region	donor +2	canonical splice dinucleotide (donor +2) · inside the BP7-excluded zone
SpliceAI	Δ0.99	donor loss, 2 bp away · masked 0 · deltas
Pangolin	Δ0.81	loss · gain 0.02 · agrees with SpliceAI · independent
Constraint at this position
Conservation	phyloP 11	GERP 1.7, phastCons 1
Overall
CADD	25.0	PHRED · no single calibrated threshold — expert panels disagree

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00167% Admixed American · 1/60,014 alleles

Overall 6.86e-05% 1/1,456,862 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: C5
Coding: c.421+2T>C
MANE Select: NM_001735
dbSNP: rs746623019
Type: single nucleotide variant
Location: chr9:121043002 (GRCh38)
Gene constraint: LOEUF 0.779 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 81.67 · 49 PDB

Full C5 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

C5 c.2257+1G>A Likely pathogenic ★★ same type
C5 c.4679-2A>G Likely pathogenic ★★ same type
C5 p.Arg1476Ter Pathogenic/Likely pathogenic ★★ same type
C5 p.Gln19Ter Pathogenic ★★ same type
C5 p.Glu1437Ter Pathogenic/Likely pathogenic ★★ same type
C5 p.Trp469Ter Pathogenic/Likely pathogenic ★★ same type
C5 c.2059+3A>G Uncertain significance ★★ same type
C5 c.3391-13T>A Uncertain significance ★★ 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/c5-c-421-plus-2t-c (accessed [today's date]).

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