Is STRADA p.Val426= (c.1278G>A) pathogenic?

STRADA p.Val426= (c.1278G>A) is classified Likely benign in STRADA (ClinVar, Single submitter, 1 submitter; last evaluated 2023-10-07). Very rare (popmax 0.0011%, sas); Associated with polyhydramnios, megalencephaly, and symptomatic epilepsy.

What condition is associated with STRADA p.Val426= (c.1278G>A)?

STRADA p.Val426= (c.1278G>A) is associated with polyhydramnios, megalencephaly, and symptomatic epilepsy (ClinVar).

How common is STRADA p.Val426= (c.1278G>A) in the general population?

STRADA p.Val426= (c.1278G>A) is very rare (popmax 0.0011%, sas) (gnomAD).

STRADA p.Val426=

Q: How is Polyhydramnios-megalencephaly-symptomatic epilepsy syndrome inherited?

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

c.1278G>A · rs780426288 · VCV2155321

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.0011%, sas)

Conditions

polyhydramnios, megalencephaly, and symptomatic epilepsy

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Pangolin	Δ0.43	gain · loss 0.00 · not in the SpliceAI release · independent
Constraint at this position
Conservation	phyloP 2.8	GERP 0.56, phastCons 1
Overall
CADD	7.882	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0011% South Asian · 1/91,064 alleles

Filtering AF 0.0005% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000366%

Overall 0.000744% 12/1,613,966 alleles · very rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0011%	91,064
European (non-Finnish)	0.000932%	107,270

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: STRADA
Protein: p.Val426=
Coding: c.1278G>A
MANE Select: NM_001003787
dbSNP: rs780426288
Type: single nucleotide variant
Location: chr17:63703617 (GRCh38)
Gene constraint: LOEUF 0.649 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 80.46 · 4 PDB
Residue 426: an α-helix

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

Disease context

polyhydramnios, megalencephaly, and symptomatic epilepsy — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Polyhydramnios-megalencephaly-symptomatic epilepsy syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Antenatal, Infancy, Neonatal

Similar variants

STRADA c.36+1G>A Likely pathogenic ★★ same condition
STRADA c.37-1G>C Likely pathogenic ★★ same condition
STRADA p.Arg228Ter Pathogenic ★★ same condition
STRADA p.Ala45Val Uncertain significance ★★ ⚠ same condition
STRADA p.Arg100Gln Uncertain significance ★★ ⚠ same condition
STRADA p.Arg13Gln Uncertain significance ★★ same condition
STRADA p.Arg13Leu Uncertain significance ★★ ⚠ same condition
STRADA p.Arg13Trp Uncertain significance ★★ ⚠ 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/strada-p-val426 (accessed [today's date]).

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