Is PREPL p.Tyr331Ter (c.993C>G) pathogenic?

PREPL p.Tyr331Ter (c.993C>G) is classified Pathogenic in PREPL (ClinVar, Single submitter, 1 submitter; last evaluated 2025-12-02). Absent from gnomAD v4.1; Associated with myasthenic syndrome, congenital, 22.

What condition is associated with PREPL p.Tyr331Ter (c.993C>G)?

PREPL p.Tyr331Ter (c.993C>G) is associated with myasthenic syndrome, congenital, 22 (ClinVar).

How common is PREPL p.Tyr331Ter (c.993C>G) in the general population?

PREPL p.Tyr331Ter (c.993C>G) is absent from gnomAD v4.1 (gnomAD).

How is Congenital myasthenic syndrome inherited?

Typically Autosomal dominant, Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

PREPL p.Tyr331Ter

c.993C>G · VCV4803657

Pathogenic Single submitter

Classification

Pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

myasthenic syndrome, congenital, 22

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 8 of 14
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP -2.8	GERP -3.4
Overall
CADD	32.0	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

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: PREPL
Protein: p.Tyr331Ter
Coding: c.993C>G
MANE Select: NM_001171613
Type: single nucleotide variant
Location: chr2:44332552 (GRCh38)
Gene constraint: LOEUF 1.247 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 82.46 · 2 PDB

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

Disease context

myasthenic syndrome, congenital, 22 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Congenital myasthenic syndrome (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive
Onset: Infancy, Neonatal
Prevalence: 1-9 / 1 000 000 (Europe)

Similar variants

PREPL p.Tyr331= Likely benign ★ same residue
PREPL c.1262+1G>A Pathogenic/Likely pathogenic ★★ same condition
PREPL c.1263-1G>C Pathogenic/Likely pathogenic ★★ same condition
PREPL c.-49+1734C>T Pathogenic/Likely pathogenic ★★ same condition
PREPL p.Arg206Ter Pathogenic/Likely pathogenic ★★ same condition
PREPL p.Gln14Ter Pathogenic/Likely pathogenic ★★ same condition
PREPL p.Gln456Ter Pathogenic/Likely pathogenic ★★ same condition
PREPL p.Glu577Ter 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/prepl-p-tyr331ter (accessed [today's date]).

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