Is AGRN p.Ser634= (c.1902C>T) pathogenic?

AGRN p.Ser634= (c.1902C>T) is classified Likely benign in AGRN (ClinVar, Multiple submitters, 3 submitters; last evaluated 2025-07-07). Rare (popmax 0.255%, sas); Associated with congenital myasthenic syndrome 8.

What condition is associated with AGRN p.Ser634= (c.1902C>T)?

AGRN p.Ser634= (c.1902C>T) is associated with congenital myasthenic syndrome 8 (ClinVar).

How common is AGRN p.Ser634= (c.1902C>T) in the general population?

AGRN p.Ser634= (c.1902C>T) is rare (popmax 0.255%, sas) (gnomAD).

AGRN p.Ser634=

c.1902C>T · rs549820648 · VCV1122911

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

rare (popmax 0.255%, sas)

Conditions

congenital myasthenic syndrome 8

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 -12	GERP -2
Overall
CADD	4.322	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.255% South Asian · 232/90,940 alleles

Filtering AF 0.228% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.218%

Overall 0.0208% 335/1,609,304 alleles · rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.255%	392
Middle Eastern	0.033%	3,026
Remaining individualsnot grpmax-eligible	0.0273%	3,668
Admixed American	0.0134%	7,488
European (non-Finnish)	0.00619%	16,158
African / African-American	0.00267%	37,505
East Asian	0.00223%	44,852

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: AGRN
Protein: p.Ser634=
Coding: c.1902C>T
MANE Select: NM_198576
dbSNP: rs549820648
Type: single nucleotide variant
Location: chr1:1043926 (GRCh38)
Gene constraint: LOEUF 0.73 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 69.79 · 1 PDB
Residue 634: the kazal-like 7 domain; a disulfide bond

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

Disease context

congenital myasthenic syndrome 8 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

AGRN c.3632-1G>C Likely pathogenic ★★ same condition
AGRN p.Arg1671Ter Pathogenic/Likely pathogenic ★★ same condition
AGRN p.Arg834Ter Pathogenic/Likely pathogenic ★★ same condition
AGRN p.Gly1582Arg Pathogenic ★★ same condition
AGRN p.Gly1675Ser Pathogenic/Likely pathogenic ★★ same condition
AGRN c.1177+4A>G Uncertain significance ★★ same condition
AGRN c.1384+6C>T Uncertain significance ★★ same condition
AGRN c.4879+4G>A 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/agrn-p-ser634 (accessed [today's date]).

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