Is CCDC8 p.Trp203Ter (c.608G>A) pathogenic?

CCDC8 p.Trp203Ter (c.608G>A) is classified Likely pathogenic in CCDC8 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-11-01). Very rare (popmax 0.0022%, sas).

How common is CCDC8 p.Trp203Ter (c.608G>A) in the general population?

CCDC8 p.Trp203Ter (c.608G>A) is very rare (popmax 0.0022%, sas) (gnomAD).

CCDC8 p.Trp203Ter

c.608G>A · VCV4535004

Likely pathogenic Single submitter

Classification

Likely pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 0.0022%, sas)

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	nonsense (stop-gain)	predicted loss-of-function
NMD	escapes	premature termination codon in the last exon (1 of 1) — the truncated protein is likely expressed. PVS1 input, not an applied code
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 3.4	GERP 1.4, phastCons 1
Overall
CADD	38.0	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 0.0022% South Asian · 2/91,054 alleles

Filtering AF 0.000365% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000137%

Overall 0.000207% 3/1,446,964 alleles · very rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0022%	45,527
Remaining individualsnot grpmax-eligible	0.0016%	62,386

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: CCDC8
Protein: p.Trp203Ter
Coding: c.608G>A
MANE Select: NM_032040
Type: single nucleotide variant
Location: chr19:46412203 (GRCh38)
Gene constraint: LOEUF 1.796 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 46.83 · 1 PDB

Full CCDC8 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

CCDC8 p.Ala217Thr Uncertain significance ★★ ⚠ same type
CCDC8 p.Ala293Thr Uncertain significance ★★ ⚠ same type
CCDC8 p.Ala393Val Uncertain significance ★★ ⚠ same type
CCDC8 p.Ala527Val Uncertain significance ★★ ⚠ same type
CCDC8 p.Arg15Gln Uncertain significance ★★ ⚠ same type
CCDC8 p.Arg225Gly Uncertain significance ★★ ⚠ same type
CCDC8 p.Arg277His Uncertain significance ★★ ⚠ same type
CCDC8 p.Arg277Ser 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/ccdc8-p-trp203ter (accessed [today's date]).

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