Is EPM2A p.Ser25Ter (c.74C>A) pathogenic?

EPM2A p.Ser25Ter (c.74C>A) is classified Pathogenic in EPM2A (ClinVar, Single submitter, 1 submitter; last evaluated 2019-01-26). Absent from gnomAD v4.1; Associated with progressive myoclonus epilepsy.

What condition is associated with EPM2A p.Ser25Ter (c.74C>A)?

EPM2A p.Ser25Ter (c.74C>A) is associated with progressive myoclonus epilepsy (ClinVar).

How common is EPM2A p.Ser25Ter (c.74C>A) in the general population?

EPM2A p.Ser25Ter (c.74C>A) is absent from gnomAD v4.1 (gnomAD).

EPM2A p.Ser25Ter

c.74C>A · rs1776817138 · VCV862225

Pathogenic Single submitter

Classification

Pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,256,444)

Conditions

progressive myoclonus epilepsy

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	nonsense (stop-gain)	predicted loss-of-function
NMD	predicted	premature termination codon in exon 1 of 4
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 10	GERP 0.64, phastCons 1
Overall
CADD	36.0	PHRED · no single calibrated threshold — expert panels disagree

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

gnomAD v4.1 · exomes + genomes

No allele count reported in gnomAD v4.1 (AN 1,256,444). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: EPM2A
Protein: p.Ser25Ter
Coding: c.74C>A
MANE Select: NM_005670
dbSNP: rs1776817138
Type: single nucleotide variant
Location: chr6:145735425 (GRCh38)
Gene constraint: LOEUF 1.191 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 34.25 · 2 PDB
Residue 25: the 'disordered' region; the cbm20 domain; a modified residue (phosphoserine; by ampk); a UniProt-annotated variant site (in melf1; atypical form; does not affect glycogen binding); a β-strand

Full EPM2A gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

progressive myoclonus epilepsy — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

EPM2A p.Ser25= Likely benign ★ same residue
EPM2A c.301+1G>T Pathogenic ★★ same condition
EPM2A c.302-1G>C Pathogenic/Likely pathogenic ★★ same condition
EPM2A c.302-2A>G Pathogenic ★★ same condition
EPM2A p.Arg108Cys Pathogenic/Likely pathogenic ★★ same condition
EPM2A p.Arg171His Pathogenic/Likely pathogenic ★★ same condition
EPM2A p.Arg241Ter Pathogenic/Likely pathogenic ★★ same condition
EPM2A p.Gly279Cys 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/epm2a-p-ser25ter (accessed [today's date]).

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