Is CTSD p.Met326Ile (c.978G>A) pathogenic?

CTSD p.Met326Ile (c.978G>A) is classified Uncertain significance in CTSD (ClinVar, Single submitter, 1 submitter; last evaluated 2022-08-12). AlphaMissense: likely benign (0.3206); Very rare (popmax 0.00267%, afr); Associated with neuronal ceroid lipofuscinosis.

What condition is associated with CTSD p.Met326Ile (c.978G>A)?

CTSD p.Met326Ile (c.978G>A) is associated with neuronal ceroid lipofuscinosis (ClinVar).

How common is CTSD p.Met326Ile (c.978G>A) in the general population?

CTSD p.Met326Ile (c.978G>A) is very rare (popmax 0.00267%, afr) (gnomAD).

What do computational predictors say about CTSD p.Met326Ile (c.978G>A)?

AlphaMissense predicts likely benign (score 0.3206) — an in-silico prediction, not a clinical call.

CTSD p.Met326Ile

c.978G>A · rs370282882 · VCV658918

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.3206 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00267%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

neuronal ceroid lipofuscinosis

Computational evidence

Protein change
AlphaMissense	0.3206	likely benign
REVEL	0.101	moderately benign-leaning
SaProt	LLR -6.11	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	Δ0.23	acceptor gain · deltas
Constraint at this position
Conservation	phyloP 0.55	phastCons 0.092
Regional constraint	o/e 0.87	unconstrained · MANE · 10 kb · p 0.0029 · regional, not allelic
Overall
CADD	19.28	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — 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 0.00267% African / African-American · 2/74,898 alleles

Filtering AF 0.000443% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000211%

Overall 0.000682% 11/1,613,272 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00267%	37,449
South Asian	0.0011%	91,036
European (non-Finnish)	0.000678%	147,452

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: CTSD
Protein: p.Met326Ile
Coding: c.978G>A
MANE Select: NM_001909
dbSNP: rs370282882
Type: single nucleotide variant
Location: chr11:1753896 (GRCh38)
Gene constraint: LOEUF 0.886 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 85.69 · 9 PDB
Residue 326: the peptidase a1 domain; a β-strand

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

Disease context

neuronal ceroid lipofuscinosis — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

CTSD p.Met326Val Uncertain significance ★ ⚠ same residue
CTSD p.Met326Lys Uncertain significance ★ ⚠ same residue
CTSD p.Met326Thr Uncertain significance ★ ⚠ same residue
CTSD c.228+1G>A Likely pathogenic ★★ same condition
CTSD p.Glu82Ter Pathogenic/Likely pathogenic ★★ same condition
CTSD c.828-3C>A Uncertain significance ★★ same condition
CTSD p.Ala10Ser Uncertain significance ★★ ⚠ same condition
CTSD p.Ala18Pro 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/ctsd-p-met326ile (accessed [today's date]).

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