Is SYNJ1 p.Pro1122Ser (c.3364C>T) pathogenic?

SYNJ1 p.Pro1122Ser (c.3364C>T) is classified Uncertain significance in SYNJ1 (ClinVar, Single submitter, 1 submitter; last evaluated 2019-07-05). Very rare (popmax 0.000175%, nfe); Associated with early-onset Parkinson disease 20.

What condition is associated with SYNJ1 p.Pro1122Ser (c.3364C>T)?

SYNJ1 p.Pro1122Ser (c.3364C>T) is associated with early-onset Parkinson disease 20, developmental and epileptic encephalopathy, 53 (ClinVar).

How common is SYNJ1 p.Pro1122Ser (c.3364C>T) in the general population?

SYNJ1 p.Pro1122Ser (c.3364C>T) is very rare (popmax 0.000175%, nfe) (gnomAD).

How is Young-onset Parkinson disease inherited?

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

SYNJ1 p.Pro1122Ser

c.3364C>T · rs1274970038 · VCV936291

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.000175%, nfe)

Conditions

early-onset Parkinson disease 20

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.576	indeterminate
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 1.6, phastCons 1
Regional constraint	o/e 0.99	unconstrained · MANE · 12 kb · p 0.77 · regional, not allelic
Overall
CADD	27.4	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000175% European (non-Finnish) · 2/1,140,094 alleles

Filtering AF 2.9e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 1.1e-05%

Overall 0.000131% 2/1,521,190 alleles · very rare exomes 2/1,368,898 · genomes 0/152,292 · joint denominator

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: SYNJ1
Protein: p.Pro1122Ser
Coding: c.3364C>T
MANE Select: NM_203446
dbSNP: rs1274970038
Type: single nucleotide variant
Location: chr21:32645673 (GRCh38)
Gene constraint: LOEUF 0.539 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 68.09 · 5 PDB
Residue 1122: the 'disordered' region

Full SYNJ1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

early-onset Parkinson disease 20 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: developmental and epileptic encephalopathy, 53

For Young-onset Parkinson disease (Orphanet):

Inheritance: Autosomal recessive
Onset: Adult
Prevalence: 1-5 / 10 000 (Europe)

Similar variants

SYNJ1 p.Pro1122Ala Uncertain significance ★ same residue
SYNJ1 c.1201-2A>G Likely pathogenic ★★ same condition
SYNJ1 c.2461+2T>C Likely pathogenic ★★ same condition
SYNJ1 c.3478+1G>A Likely pathogenic ★★ same condition
SYNJ1 p.Arg219Gln Pathogenic ★★ same condition
SYNJ1 p.Arg534Ter Pathogenic/Likely pathogenic ★★ same condition
SYNJ1 p.Arg709Ter Pathogenic/Likely pathogenic ★★ same condition
SYNJ1 p.Gln748Ter 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/synj1-p-pro1122ser (accessed [today's date]).

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