Is CTSB p.Val191Ile (c.571G>A) pathogenic?

CTSB p.Val191Ile (c.571G>A) is classified Uncertain significance in CTSB (ClinVar, Single submitter, 1 submitter; last evaluated 2022-06-13). AlphaMissense: likely benign (0.0954); Very rare (popmax 0.00563%, sas).

How common is CTSB p.Val191Ile (c.571G>A) in the general population?

CTSB p.Val191Ile (c.571G>A) is very rare (popmax 0.00563%, sas) (gnomAD).

What do computational predictors say about CTSB p.Val191Ile (c.571G>A)?

AlphaMissense predicts likely benign (score 0.0954) — an in-silico prediction, not a clinical call.

CTSB p.Val191Ile

c.571G>A · rs984397185 · VCV1492718

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.0954 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00563%, sas)

Missense predictors

0/2 damaging

AlphaMissense, SaProt · REVEL no call

Computational evidence

Protein change
AlphaMissense	0.0954	likely benign
REVEL	0.499	indeterminate
SaProt	LLR -7.21	tolerated
⇒ AlphaMissense and SaProt both call this tolerated; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 5.9	GERP 0.7, phastCons 1
Regional constraint	o/e 1.73	unconstrained · MANE · 8,326 bp · p 8.5e-54 · regional, not allelic
Overall
CADD	23.0	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 0.00563% South Asian · 5/88,830 alleles

Filtering AF 0.00214% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00139%

Overall 0.00169% 27/1,598,442 alleles · very rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.00563%	17,766
Admixed American	0.0037%	27,028
Remaining individualsnot grpmax-eligible	0.00324%	30,894
Finnishnot grpmax-eligible	0.00157%	63,890
European (non-Finnish)	0.00136%	73,483
African / African-American	0.00136%	73,734

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: CTSB
Protein: p.Val191Ile
Coding: c.571G>A
MANE Select: NM_001908
dbSNP: rs984397185
Type: single nucleotide variant
Location: chr8:11847784 (GRCh38)
Gene constraint: LOEUF 1.756 · pLI <0.01 · ClinGen HI 0/3 (gnomAD)
Structure: AlphaFold pLDDT 91.95 · 21 PDB
Residue 191: a disulfide bond; a β-strand

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

Similar variants

CTSB p.Arg331Pro Uncertain significance ★★ ⚠ same type
CTSB p.Asp333Asn Uncertain significance ★★ ⚠ same type
CTSB p.Lys220Glu Uncertain significance ★★ ⚠ same type
CTSB p.Met73Thr Uncertain significance ★★ ⚠ same type
CTSB p.Thr332Ala Uncertain significance ★★ ⚠ same type
CTSB c.327+20C>T Benign ★★ same type
CTSB c.446+9G>C Benign ★★ same type
CTSB c.447-16G>C Benign ★★ same type

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/ctsb-p-val191ile (accessed [today's date]).

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