Is SPAST p.Ser445Arg (c.1335C>A) pathogenic?

SPAST p.Ser445Arg (c.1335C>A) is classified Pathogenic in SPAST (ClinVar, No assertion criteria, 1 submitter; last evaluated 2006-07-11). AlphaMissense: likely pathogenic (0.9996); Very rare (popmax 8.48e-05%, nfe); Associated with hereditary spastic paraplegia 4.

What condition is associated with SPAST p.Ser445Arg (c.1335C>A)?

SPAST p.Ser445Arg (c.1335C>A) is associated with hereditary spastic paraplegia 4 (ClinVar).

How common is SPAST p.Ser445Arg (c.1335C>A) in the general population?

SPAST p.Ser445Arg (c.1335C>A) is very rare (popmax 8.48e-05%, nfe) (gnomAD).

How is Autosomal dominant spastic paraplegia type 4 inherited?

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

What do computational predictors say about SPAST p.Ser445Arg (c.1335C>A)?

AlphaMissense predicts likely pathogenic (score 0.9996) — an in-silico prediction, not a clinical call.

SPAST p.Ser445Arg

c.1335C>A · rs121908519 · VCV5676

Pathogenic No assertion criteria

Classification

Pathogenic

ClinVar

Review

No assertion criteria ☆☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely pathogenic

0.9996 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 8.48e-05%, nfe)

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

hereditary spastic paraplegia 4

Computational evidence

Protein change
AlphaMissense	0.9996	likely pathogenic ✓ concordant with ClinVar · top 1% in SPAST
REVEL	0.837	moderately pathogenic-leaning
SaProt	LLR -12.29	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 0.78	GERP -1.4, phastCons 1
Regional constraint	o/e 0.39	unconstrained · MANE · 26 kb · p 1.7e-17 · regional, not allelic
Overall
CADD	23.8	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 8.48e-05% European (non-Finnish) · 1/1,179,140 alleles

Overall 6.2e-05% 1/1,612,944 alleles · very rare exomes 1/1,460,822 · genomes 0/152,122 · 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: SPAST
Protein: p.Ser445Arg
Coding: c.1335C>A
MANE Select: NM_014946
dbSNP: rs121908519
Type: single nucleotide variant
Location: chr2:32136890 (GRCh38)
Gene constraint: LOEUF 0.69 · pLI 0.11 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 77.03 · 7 PDB
Residue 445: a UniProt-annotated variant site (in spg4; uncertain significance); the 'sufficient for microtubule severing' region; an α-helix; a UniProt-annotated variant site (in spg4)

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

Disease context

hereditary spastic paraplegia 4 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Autosomal dominant spastic paraplegia type 4 (Orphanet):

Inheritance: Autosomal dominant
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: 1-9 / 1 000 000 (Portugal)

Similar variants

SPAST p.Ser445Asn Uncertain significance ★ ⚠ same residue
SPAST p.Ser445Thr Likely pathogenic ★ ⚠ same residue
SPAST c.1004+1G>C Pathogenic/Likely pathogenic ★★ same condition
SPAST c.1004+1G>T Pathogenic ★★ same condition
SPAST c.1004+2T>G Pathogenic ★★ same condition
SPAST c.1098+1G>A Pathogenic ★★ same condition
SPAST c.1099-1G>A Pathogenic ★★ same condition
SPAST c.1099-2A>C 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/spast-p-ser445arg (accessed [today's date]).

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