Is PRRT2 p.Cys278= (c.834C>T) pathogenic?

PRRT2 p.Cys278= (c.834C>T) is classified Likely benign in PRRT2 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-09-08). Ultra-rare (popmax 0.0223%, eas); Associated with episodic kinesigenic dyskinesia.

What condition is associated with PRRT2 p.Cys278= (c.834C>T)?

PRRT2 p.Cys278= (c.834C>T) is associated with episodic kinesigenic dyskinesia (ClinVar).

How common is PRRT2 p.Cys278= (c.834C>T) in the general population?

PRRT2 p.Cys278= (c.834C>T) is ultra-rare (popmax 0.0223%, eas) (gnomAD).

How is Paroxysmal kinesigenic dyskinesia inherited?

Typically Autosomal dominant, Not applicable (Orphanet). A genetic counselor can assess individual risk for a family.

PRRT2 p.Cys278=

c.834C>T · rs758654999 · VCV512161

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0223%, eas)

Conditions

episodic kinesigenic dyskinesia

⚠ Built without this gene's context — gene constraint and dosage, protein structure, pathways, panels and related-variant links were not looked up for this page. why

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not looked up on this page · why
Constraint at this position
Conservation	phyloP 7.6	GERP 0.61, phastCons 1
Overall
CADD	13.35	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0223% East Asian · 10/44,882 alleles

Filtering AF 0.012% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00916%

Overall 0.000745% 12/1,610,984 alleles · ultra-rare exomes 10/1,458,820 · genomes 2/152,164 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.0223%	4,488
Remaining individualsnot grpmax-eligible	0.00321%	31,167

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: PRRT2
Protein: p.Cys278=
Coding: c.834C>T
MANE Select: NM_145239
dbSNP: rs758654999
Type: single nucleotide variant
Location: chr16:29813888 (GRCh38)

Full PRRT2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

episodic kinesigenic dyskinesia — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Paroxysmal kinesigenic dyskinesia (Orphanet):

Inheritance: Autosomal dominant, Not applicable
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: 1-9 / 1 000 000 (Worldwide)

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/prrt2-p-cys278 (accessed [today's date]).

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