Is ARX p.Glu124= (c.372G>A) pathogenic?

ARX p.Glu124= (c.372G>A) is classified Likely benign in ARX (ClinVar, Single submitter, 1 submitter; last evaluated 2025-12-29). Very rare (popmax 0.000313%, nfe); Associated with developmental and epileptic encephalopathy, 1.

What condition is associated with ARX p.Glu124= (c.372G>A)?

ARX p.Glu124= (c.372G>A) is associated with developmental and epileptic encephalopathy, 1, intellectual disability, X-linked, with or without seizures, ARX-related (ClinVar).

How common is ARX p.Glu124= (c.372G>A) in the general population?

ARX p.Glu124= (c.372G>A) is very rare (popmax 0.000313%, nfe) (gnomAD).

How is Infantile epileptic spasms syndrome inherited?

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

ARX p.Glu124=

c.372G>A · rs1006764242 · VCV699662

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.000313%, nfe)

Conditions

developmental and epileptic encephalopathy, 1

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 0.13	GERP 0.15, phastCons 0.92
Overall
CADD	11.74	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000313% European (non-Finnish) · 2/639,440 alleles

Filtering AF 5.2e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 2e-05%

Overall 0.000266% 2/751,164 alleles · very rare

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: ARX
Protein: p.Glu124=
Coding: c.372G>A
MANE Select: NM_139058
dbSNP: rs1006764242
Type: single nucleotide variant
Location: chrX:25013623 (GRCh38)
Structure: AlphaFold pLDDT 56.51
Residue 124: the 'disordered' region

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

Disease context

developmental and epileptic encephalopathy, 1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: intellectual disability, X-linked, with or without seizures, ARX-related

For Infantile epileptic spasms syndrome (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive, X-linked dominant

Similar variants

ARX p.Glu124Ter Pathogenic ★ same residue
ARX p.Glu124Val Uncertain significance ★ same residue
ARX p.Arg330His Likely pathogenic ★★ same condition
ARX p.Arg332Gly Pathogenic/Likely pathogenic ★★ same condition
ARX p.Arg332His Pathogenic ★★ same condition
ARX p.Arg371Gln Likely pathogenic ★★ same condition
ARX p.Arg371Ter Pathogenic ★★ same condition
ARX p.Arg384Cys Pathogenic/Likely pathogenic ★★ 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/arx-p-glu124 (accessed [today's date]).

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