Is GRIN2B p.Pro122= (c.366C>A) pathogenic?

GRIN2B p.Pro122= (c.366C>A) is classified Likely benign in GRIN2B (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-07-30). Very rare (popmax 0.00769%, sas); Associated with developmental and epileptic encephalopathy, 27.

What condition is associated with GRIN2B p.Pro122= (c.366C>A)?

GRIN2B p.Pro122= (c.366C>A) is associated with developmental and epileptic encephalopathy, 27, intellectual disability, autosomal dominant 6 (ClinVar).

How common is GRIN2B p.Pro122= (c.366C>A) in the general population?

GRIN2B p.Pro122= (c.366C>A) is very rare (popmax 0.00769%, 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.

GRIN2B p.Pro122=

c.366C>A · rs7301328 · VCV1213277

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00769%, sas)

Conditions

developmental and epileptic encephalopathy, 27

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP -0.19	GERP -1.1, phastCons 0.019
Overall
CADD	5.218	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00769% South Asian · 7/91,046 alleles

Filtering AF 0.00359% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00255%

Overall 0.000496% 8/1,613,732 alleles · very rare exomes 7/1,461,780 · genomes 1/151,952 · joint denominator

Ancestry group	Frequency	1 in
South Asiangrpmax	0.00769%	13,007
Remaining individualsnot grpmax-eligible	0.0016%	62,494

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: GRIN2B
Protein: p.Pro122=
Coding: c.366C>A
MANE Select: NM_000834
dbSNP: rs7301328
Type: single nucleotide variant
Location: chr12:13865843 (GRCh38)
Gene constraint: LOEUF 0.102 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 60.66 · 36 PDB

Full GRIN2B gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

developmental and epileptic encephalopathy, 27 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: intellectual disability, autosomal dominant 6

For Infantile epileptic spasms syndrome (Orphanet):

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

Similar variants

GRIN2B p.Pro122Ser Conflicting classifications of pathogenicity ★ ⚠ same residue
GRIN2B c.2172-2A>G Pathogenic ★★ same condition
GRIN2B p.Ala639Val Pathogenic/Likely pathogenic ★★ same condition
GRIN2B p.Ala644Asp Pathogenic ★★ same condition
GRIN2B p.Ala734Val Likely pathogenic ★★ same condition
GRIN2B p.Ala819Thr Pathogenic/Likely pathogenic ★★ same condition
GRIN2B p.Arg1111His Pathogenic/Likely pathogenic ★★ ⚠ same condition
GRIN2B p.Arg393Ter 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/grin2b-p-pro122 (accessed [today's date]).

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