Is COG4 p.Asn644Ser (c.1931A>G) pathogenic?

COG4 p.Asn644Ser (c.1931A>G) is classified Uncertain significance in COG4 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-01-20). Ultra-rare (popmax 0.0214%, afr); Associated with COG4-congenital disorder of glycosylation.

What condition is associated with COG4 p.Asn644Ser (c.1931A>G)?

COG4 p.Asn644Ser (c.1931A>G) is associated with COG4-congenital disorder of glycosylation (ClinVar).

How common is COG4 p.Asn644Ser (c.1931A>G) in the general population?

COG4 p.Asn644Ser (c.1931A>G) is ultra-rare (popmax 0.0214%, afr) (gnomAD).

How is COG4-CDG inherited?

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

COG4 p.Asn644Ser

c.1931A>G · rs144763147 · VCV1002699

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0214%, afr)

Conditions

COG4-congenital disorder of glycosylation

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.08	moderately benign-leaning
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 6.1	GERP 1.6, phastCons 1
Regional constraint	o/e 1.06	unconstrained · MANE · 43 kb · p 0.075 · regional, not allelic
Overall
CADD	17.94	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0214% African / African-American · 16/74,876 alleles

Filtering AF 0.0133% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0109%

Overall 0.00366% 59/1,612,518 alleles · ultra-rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.0214%	4,680
Admixed American	0.00667%	15,001
European (non-Finnish)	0.00314%	31,856
East Asian	0.00223%	44,888
Remaining individualsnot grpmax-eligible	0.0016%	62,436

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: COG4
Protein: p.Asn644Ser
Coding: c.1931A>G
MANE Select: NM_015386
dbSNP: rs144763147
Type: single nucleotide variant
Location: chr16:70482165 (GRCh38)
Gene constraint: LOEUF 0.805 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 85.29 · 1 PDB
Residue 644: an α-helix; the 'd domain' region

Full COG4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

COG4-congenital disorder of glycosylation — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For COG4-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

COG4 p.Arg177Ter Pathogenic/Likely pathogenic ★★ same condition
COG4 p.Arg733Trp Pathogenic/Likely pathogenic ★★ same condition
COG4 p.Glu614Ter Pathogenic ★★ same condition
COG4 p.Gly25Ter Pathogenic/Likely pathogenic ★★ same condition
COG4 p.Gly516Arg Pathogenic ★★ same condition
COG4 p.Ala251Thr Uncertain significance ★★ same condition
COG4 p.Ala544Val Uncertain significance ★★ same condition
COG4 p.Arg198His 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/cog4-p-asn644ser (accessed [today's date]).

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