Is COG1 p.Pro109= (c.327A>G) pathogenic?

COG1 p.Pro109= (c.327A>G) is classified Likely benign in COG1 (ClinVar, Single submitter, 1 submitter; last evaluated 2022-10-14). Very rare (popmax 0.00133%, afr); Associated with COG1-congenital disorder of glycosylation.

What condition is associated with COG1 p.Pro109= (c.327A>G)?

COG1 p.Pro109= (c.327A>G) is associated with COG1-congenital disorder of glycosylation (ClinVar).

How common is COG1 p.Pro109= (c.327A>G) in the general population?

COG1 p.Pro109= (c.327A>G) is very rare (popmax 0.00133%, afr) (gnomAD).

How is COG1-CDG inherited?

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

COG1 p.Pro109=

c.327A>G · rs1006731213 · VCV2415564

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00133%, afr)

Conditions

COG1-congenital disorder of glycosylation

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -14	GERP -15
Overall
CADD	0.136	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00133% African / African-American · 1/74,922 alleles

Filtering AF 6.8e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 1.9e-05%

Overall 0.000248% 4/1,614,082 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00133%	74,922
European (non-Finnish)	0.000254%	393,349

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: COG1
Protein: p.Pro109=
Coding: c.327A>G
MANE Select: NM_018714
dbSNP: rs1006731213
Type: single nucleotide variant
Location: chr17:73196518 (GRCh38)
Gene constraint: LOEUF 0.718 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 77.82

Full COG1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

COG1-congenital disorder of glycosylation — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For COG1-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

COG1 c.1070+5G>A Pathogenic ★★ same condition
COG1 p.Arg336Ter Pathogenic ★★ same condition
COG1 p.Trp476Ter Pathogenic/Likely pathogenic ★★ same condition
COG1 p.Ala143Thr Uncertain significance ★★ ⚠ same condition
COG1 p.Ala209Val Uncertain significance ★★ ⚠ same condition
COG1 p.Ala27Ser Uncertain significance ★★ ⚠ same condition
COG1 p.Ala380Val Uncertain significance ★★ ⚠ same condition
COG1 p.Ala385Thr 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/cog1-p-pro109 (accessed [today's date]).

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