Is AGRN p.Arg34= (c.102C>T) pathogenic?

AGRN p.Arg34= (c.102C>T) is classified Likely benign in AGRN (ClinVar, Single submitter, 1 submitter; last evaluated 2023-12-09). Ultra-rare (popmax 0.0231%, mid); Associated with congenital myasthenic syndrome 8.

What condition is associated with AGRN p.Arg34= (c.102C>T)?

AGRN p.Arg34= (c.102C>T) is associated with congenital myasthenic syndrome 8 (ClinVar).

How common is AGRN p.Arg34= (c.102C>T) in the general population?

AGRN p.Arg34= (c.102C>T) is ultra-rare (popmax 0.0231%, mid) (gnomAD).

AGRN p.Arg34=

c.102C>T · rs1033464887 · VCV645701

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0231%, mid)

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 2.2	GERP -0.85, phastCons 1
Overall
CADD	14.56	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0231% Middle Eastern · 1/4,322 alleles

Filtering AF 0.00603% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0041%

Overall 0.0047% 69/1,469,460 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0231%	4,322
Admixed American	0.014%	7,118
European (non-Finnish)	0.00549%	18,204
African / African-American	0.00147%	68,054

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.Arg34=
Coding: c.102C>T
MANE Select: NM_198576
dbSNP: rs1033464887
Type: single nucleotide variant
Location: chr1:1020274 (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 34: a disulfide bond; the nta domain

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-arg34 (accessed [today's date]).

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