Is CBS p.Ala446Val (c.1337C>T) pathogenic?

CBS p.Ala446Val (c.1337C>T) is classified Uncertain significance in CBS (ClinVar, Multiple submitters, 3 submitters; last evaluated 2022-07-18). AlphaMissense: likely benign (0.0756); Absent from gnomAD v4.1; Associated with HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED.

What condition is associated with CBS p.Ala446Val (c.1337C>T)?

CBS p.Ala446Val (c.1337C>T) is associated with HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED, classic homocystinuria (ClinVar).

How common is CBS p.Ala446Val (c.1337C>T) in the general population?

CBS p.Ala446Val (c.1337C>T) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about CBS p.Ala446Val (c.1337C>T)?

AlphaMissense predicts likely benign (score 0.0756) — an in-silico prediction, not a clinical call.

CBS p.Ala446Val

c.1337C>T · rs757347527 · VCV568107

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

AlphaMissense

likely benign

0.0756 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED

Computational evidence

Protein change
AlphaMissense	0.0756	likely benign
REVEL	0.192	benign-leaning
SaProt	LLR -8.01	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	Δ0.97	donor gain · deltas
Pangolin	Δ0.78	gain · loss 0.23 · agrees with SpliceAI · independent
Constraint at this position
Conservation	phyloP 0.64	GERP 0.15, phastCons 0.043
Regional constraint	o/e 0.00	constrained · MANE · 11 kb · p 6.7e-07 · regional, not allelic
Overall
CADD	23.6	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

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: CBS
Protein: p.Ala446Val
Coding: c.1337C>T
MANE Select: NM_000071
dbSNP: rs757347527
Type: single nucleotide variant
Location: chr21:43058855 (GRCh38)
Structure: AlphaFold pLDDT 90.15 · 28 PDB
Residue 446: the cbs domain; a UniProt-annotated variant site (in cbsd); a β-strand

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

Disease context

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: classic homocystinuria

Similar variants

CBS p.Ala446= Likely benign ★ same residue
CBS c.1145+1G>A Pathogenic/Likely pathogenic ★★ same condition
CBS c.1223+1G>T Pathogenic ★★ same condition
CBS c.1224-2A>C Pathogenic ★★ same condition
CBS c.1358+1G>A Pathogenic ★★ same condition
CBS c.1359-1G>C Pathogenic/Likely pathogenic ★★ same condition
CBS c.1468-1G>A Likely pathogenic ★★ same condition
CBS c.1552+1G>A 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/cbs-p-ala446val (accessed [today's date]).

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