Is IQSEC2 p.Pro276Ser (c.826C>T) pathogenic?

IQSEC2 p.Pro276Ser (c.826C>T) is classified Uncertain significance in IQSEC2 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-06-30). AlphaMissense: likely benign (0.0595); Absent from gnomAD v4.1; Associated with intellectual disability, X-linked 1.

What condition is associated with IQSEC2 p.Pro276Ser (c.826C>T)?

IQSEC2 p.Pro276Ser (c.826C>T) is associated with intellectual disability, X-linked 1 (ClinVar).

How common is IQSEC2 p.Pro276Ser (c.826C>T) in the general population?

IQSEC2 p.Pro276Ser (c.826C>T) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about IQSEC2 p.Pro276Ser (c.826C>T)?

AlphaMissense predicts likely benign (score 0.0595) — an in-silico prediction, not a clinical call.

IQSEC2 p.Pro276Ser

Q: How is Severe intellectual disability-progressive postnatal microcephaly-midline stereotypic hand movements syndrome inherited?

Typically X-linked recessive (Orphanet). A genetic counselor can assess individual risk for a family.

c.826C>T · rs1556865113 · VCV2734409

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.0595 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

intellectual disability, X-linked 1

Computational evidence

Protein change
AlphaMissense	0.0595	likely benign
REVEL	0.221	benign-leaning
SaProt	LLR -6.49	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 0.92	GERP -3.6, phastCons 1
Regional constraint	o/e 0.87	unconstrained · MANE · 213 bp · p 0.3 · regional, not allelic
Overall
CADD	7.21	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — 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: IQSEC2
Protein: p.Pro276Ser
Coding: c.826C>T
MANE Select: NM_001111125
dbSNP: rs1556865113
Type: single nucleotide variant
Location: chrX:53255973 (GRCh38)
Structure: AlphaFold pLDDT 54.46 · 2 PDB
Residue 276: the 'disordered' region

Full IQSEC2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

intellectual disability, X-linked 1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Severe intellectual disability-progressive postnatal microcephaly-midline stereotypic hand movements syndrome (Orphanet):

Inheritance: X-linked recessive
Onset: Infancy, Neonatal

Similar variants

IQSEC2 p.Pro276Ala Uncertain significance ★★ ⚠ same residue
IQSEC2 p.Pro276His Uncertain significance ★★ ⚠ same residue
IQSEC2 p.Pro276Thr Uncertain significance ★★ ⚠ same residue
IQSEC2 p.Pro276Leu Uncertain significance ★ ⚠ same residue
IQSEC2 c.2459+21C>T Pathogenic ★★ same condition
IQSEC2 c.2889+1G>A Pathogenic ★★ same condition
IQSEC2 p.Ala836Val Pathogenic/Likely pathogenic ★★ same condition
IQSEC2 p.Arg1055Ter 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/iqsec2-p-pro276ser (accessed [today's date]).

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