Is ARX p.Arg330Cys (c.988C>T) pathogenic?

ARX p.Arg330Cys (c.988C>T) is classified Uncertain significance in ARX (ClinVar, Single submitter, 1 submitter; last evaluated 2023-10-31). AlphaMissense: likely pathogenic (0.9997); Absent from gnomAD v4.1; Associated with intellectual disability, X-linked, with or without seizures, ARX-related.

How common is ARX p.Arg330Cys (c.988C>T) in the general population?

ARX p.Arg330Cys (c.988C>T) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about ARX p.Arg330Cys (c.988C>T)?

AlphaMissense predicts likely pathogenic (score 0.9997) — an in-silico prediction, not a clinical call.

ARX p.Arg330Cys

Q: What condition is associated with ARX p.Arg330Cys (c.988C>T)?

ARX p.Arg330Cys (c.988C>T) is associated with intellectual disability, X-linked, with or without seizures, ARX-related, developmental and epileptic encephalopathy, 1 (ClinVar).

c.988C>T · rs2519106352 · VCV2953437

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely pathogenic

0.9997 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

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

Computational evidence

Protein change
AlphaMissense	0.9997	likely pathogenic · top 4% in ARX
REVEL	0.917	moderately pathogenic-leaning
SaProt	LLR -15.90	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 11	GERP 2.1, phastCons 1
Regional constraint	o/e 0.27	constrained · MANE · 5,714 bp · p 1e-11 · regional, not allelic
Overall
CADD	34.0	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean damaging — a triage signal, not a reclassification

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: ARX
Protein: p.Arg330Cys
Coding: c.988C>T
MANE Select: NM_139058
dbSNP: rs2519106352
Type: single nucleotide variant
Location: chrX:25013007 (GRCh38)
Structure: AlphaFold pLDDT 56.51
Residue 330: a DNA-binding region

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

Disease context

intellectual disability, X-linked, with or without seizures, ARX-related — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: developmental and epileptic encephalopathy, 1

Similar variants

ARX p.Arg330His Likely pathogenic ★★ same residue
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
ARX p.Glu294Ter Pathogenic ★★ same condition
ARX p.Pro353Leu 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-arg330cys (accessed [today's date]).

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