Is CBS p.Pro229= (c.687C>T) pathogenic?

CBS p.Pro229= (c.687C>T) is classified Likely benign in CBS (ClinVar, Multiple submitters, 5 submitters; last evaluated 2026-04-03). Very rare (popmax 0.00894%, eas); Associated with familial thoracic aortic aneurysm and aortic dissection.

How common is CBS p.Pro229= (c.687C>T) in the general population?

CBS p.Pro229= (c.687C>T) is very rare (popmax 0.00894%, eas) (gnomAD).

CBS p.Pro229=

Q: What condition is associated with CBS p.Pro229= (c.687C>T)?

CBS p.Pro229= (c.687C>T) is associated with familial thoracic aortic aneurysm and aortic dissection, classic homocystinuria (ClinVar).

Q: How is Familial thoracic aortic aneurysm and aortic dissection inherited?

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

c.687C>T · rs769298649 · VCV703635

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 5 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00894%, eas)

Conditions

familial thoracic aortic aneurysm and aortic dissection

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -1.1	GERP -2.5
Overall
CADD	7.93	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00894% East Asian · 4/44,744 alleles

Filtering AF 0.00298% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0018%

Overall 0.000916% 13/1,418,446 alleles · very rare

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00894%	11,186
Admixed American	0.00359%	27,876
African / African-American	0.00149%	67,010
European (non-Finnish)	0.000588%	170,126

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: CBS
Protein: p.Pro229=
Coding: c.687C>T
MANE Select: NM_000071
dbSNP: rs769298649
Type: single nucleotide variant
Location: chr21:43065252 (GRCh38)
Structure: AlphaFold pLDDT 90.15 · 28 PDB
Residue 229: an α-helix

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

Disease context

familial thoracic aortic aneurysm and aortic dissection — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: classic homocystinuria

For Familial thoracic aortic aneurysm and aortic dissection (Orphanet):

Inheritance: Autosomal dominant
Onset: Adolescent, Adult, Childhood

Similar variants

CBS p.Pro229Thr Conflicting classifications of pathogenicity ★ ⚠ 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-pro229 (accessed [today's date]).

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