Is CTSA p.Ser178Thr (c.533G>C) pathogenic?

CTSA p.Ser178Thr (c.533G>C) is classified Uncertain significance in CTSA (ClinVar, Multiple submitters, 2 submitters; last evaluated 2024-11-21). AlphaMissense: likely pathogenic (0.9763); Very rare (popmax 0.005%, amr); Associated with galactosialidosis.

What condition is associated with CTSA p.Ser178Thr (c.533G>C)?

CTSA p.Ser178Thr (c.533G>C) is associated with galactosialidosis (ClinVar).

How common is CTSA p.Ser178Thr (c.533G>C) in the general population?

CTSA p.Ser178Thr (c.533G>C) is very rare (popmax 0.005%, amr) (gnomAD).

How is Galactosialidosis inherited?

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

What do computational predictors say about CTSA p.Ser178Thr (c.533G>C)?

AlphaMissense predicts likely pathogenic (score 0.9763) — an in-silico prediction, not a clinical call.

CTSA p.Ser178Thr

c.533G>C · rs757124963 · VCV862347

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely pathogenic

0.9763 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.005%, amr)

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

galactosialidosis

Computational evidence

Protein change
AlphaMissense	0.9763	likely pathogenic · top 10% in CTSA
REVEL	0.944	strongly pathogenic-leaning
SaProt	LLR -14.85	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
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 0.92	unconstrained · MANE · 1,710 bp · p 0.19 · regional, not allelic
Overall
CADD	28.3	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean damaging — a triage signal, not a reclassification

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.005% Admixed American · 3/60,002 alleles

Filtering AF 0.00133% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000668%

Overall 0.000186% 3/1,614,020 alleles · very rare

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: CTSA
Protein: p.Ser178Thr
Coding: c.533G>C
MANE Select: NM_000308
dbSNP: rs757124963
Type: single nucleotide variant
Location: chr20:45892813 (GRCh38)
Gene constraint: LOEUF 0.851 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 94.59 · 12 PDB
Residue 178: an active site; a disulfide bond

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

Disease context

galactosialidosis — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Galactosialidosis (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages

Similar variants

CTSA c.1-2A>G Pathogenic/Likely pathogenic ★★ same condition
CTSA c.358-2A>G Likely pathogenic ★★ same condition
CTSA c.601-2A>G Pathogenic/Likely pathogenic ★★ same condition
CTSA c.692+3A>G Pathogenic ★★ same condition
CTSA c.948+1G>A Likely pathogenic ★★ same condition
CTSA p.Arg375Ter Pathogenic/Likely pathogenic ★★ same condition
CTSA p.Cys256Ter Pathogenic/Likely pathogenic ★★ same condition
CTSA p.Cys281Ter 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/ctsa-p-ser178thr (accessed [today's date]).

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