Is ARX p.Pro424= (c.1272G>T) pathogenic?

ARX p.Pro424= (c.1272G>T) is classified Benign/Likely benign in ARX (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-12-03). Rare (popmax 0.138%, sas); Associated with developmental and epileptic encephalopathy, 1.

What condition is associated with ARX p.Pro424= (c.1272G>T)?

ARX p.Pro424= (c.1272G>T) is associated with developmental and epileptic encephalopathy, 1, intellectual disability, X-linked, with or without seizures, ARX-related (ClinVar).

How common is ARX p.Pro424= (c.1272G>T) in the general population?

ARX p.Pro424= (c.1272G>T) is rare (popmax 0.138%, sas) (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.Pro424=

c.1272G>T · rs398124507 · VCV379821

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

rare (popmax 0.138%, sas)

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 -8.1	GERP -3.9
Overall
CADD	0.13	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.138% South Asian · 63/45,623 alleles

Filtering AF 0.111% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.101%

Overall 0.006% 67/1,117,406 alleles · rare exomes 67/1,004,140 · genomes 0/113,266 · joint denominator

Ancestry group	Frequency	1 in
South Asiangrpmax	0.138%	724
Remaining individualsnot grpmax-eligible	0.00683%	14,632
European (non-Finnish)	0.000117%	855,879

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.Pro424=
Coding: c.1272G>T
MANE Select: NM_139058
dbSNP: rs398124507
Type: single nucleotide variant
Location: chrX:25007287 (GRCh38)
Structure: AlphaFold pLDDT 56.51

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.Pro424Leu Uncertain significance ★★ ⚠ same residue
ARX p.Pro424Ala 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-pro424 (accessed [today's date]).

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