Is CTRB2 p.Ile121Leu (c.361A>C) pathogenic?

CTRB2 p.Ile121Leu (c.361A>C) is classified Uncertain significance in CTRB2 (ClinVar, Single submitter, 1 submitter; last evaluated 2025-03-26). AlphaMissense: likely benign (0.2892); Ultra-rare (popmax 0.0149%, nfe).

How common is CTRB2 p.Ile121Leu (c.361A>C) in the general population?

CTRB2 p.Ile121Leu (c.361A>C) is ultra-rare (popmax 0.0149%, nfe) (gnomAD).

What do computational predictors say about CTRB2 p.Ile121Leu (c.361A>C)?

AlphaMissense predicts likely benign (score 0.2892) — an in-silico prediction, not a clinical call.

CTRB2 p.Ile121Leu

c.361A>C · VCV4008103

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.2892 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0149%, nfe)

Missense predictors

1/3 damaging

AlphaMissense, REVEL, SaProt

Computational evidence

Protein change
AlphaMissense	0.2892	likely benign
REVEL	0.661	pathogenic-leaning
SaProt	LLR -9.63	tolerated
⇒ REVEL calls this damaging; AlphaMissense and SaProt do not.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.3	GERP 1.3, phastCons 1
Regional constraint	o/e 0.09	constrained · MANE · 1,077 bp · p 4.7e-13 · regional, not allelic
Overall
CADD	23.2	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 0.0149% European (non-Finnish) · 46/307,958 alleles

Filtering AF 0.0114% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0102%

Overall 0.0103% 50/483,882 alleles · ultra-rare

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.0149%	6,695
Admixed American	0.0134%	7,451
Remaining individualsnot grpmax-eligible	0.00446%	22,436

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: CTRB2
Protein: p.Ile121Leu
Coding: c.361A>C
MANE Select: NM_001025200
Type: single nucleotide variant
Location: chr16:75205468 (GRCh38)
Gene constraint: LOEUF 1.168 · pLI 0.36 (gnomAD)
Structure: AlphaFold pLDDT 91.79
Residue 121: the peptidase s1 domain; a disulfide bond

Full CTRB2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Similar variants

CTRB2 p.Ala11Thr Uncertain significance ★ ⚠ same type
CTRB2 p.Ala138Thr Uncertain significance ★ ⚠ same type
CTRB2 p.Ala244Thr Uncertain significance ★ ⚠ same type
CTRB2 p.Arg131His Uncertain significance ★ ⚠ same type
CTRB2 p.Arg236Cys Uncertain significance ★ ⚠ same type
CTRB2 p.Arg236His Uncertain significance ★ ⚠ same type
CTRB2 p.Arg248Cys Uncertain significance ★ ⚠ same type
CTRB2 p.Asn167Tyr Uncertain significance ★ ⚠ 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/ctrb2-p-ile121leu (accessed [today's date]).

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