Homocystinuria: genes and variants
Explore variant evidence for Homocystinuria across 1 analyzed protein (CBS). Linked ClinVar records include 51 pathogenic or likely pathogenic variants, 0 variants of uncertain significance and 4 with conflicting classifications.
Coverage includes proteins already analyzed in CATVariant, not every gene involved in this condition. Database links are associations, not an assessment of clinical gene–disease validity. Computable evidence prioritizes variants for expert review and does not reclassify them. Counts refer to the selected disease label.
Data updated 2026-10-11. Automated aggregation, not a clinical review date.
Download variant evidence (CSV)
Genes linked to Homocystinuria
CBS: Cystathionine beta-synthase
A vitamin B6-dependent enzyme that combines homocysteine and serine to form cystathionine in the transsulfuration pathway. Deficiency causes homocystinuria.
51 ClinVar pathogenic / likely pathogenic and 4 uncertain variants in CBS have source records linked to Homocystinuria. Association strength is not clinical gene validity.
ClinVar pathogenic and likely pathogenic variants linked to Homocystinuria
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| CBS A114T | 114 | Pathogenic / likely pathogenic (★★) | |
| CBS R121H | 121 | Pathogenic / likely pathogenic (★★) | |
| CBS R125W | 125 | Pathogenic / likely pathogenic (★★) | |
| CBS N228K | 228 | Pathogenic / likely pathogenic (★★) | |
| CBS R336C | 336 | Pathogenic / likely pathogenic (★★) | |
| CBS R379Q | 379 | Pathogenic / likely pathogenic (★★) | |
| CBS R379W | 379 | Pathogenic / likely pathogenic (★★) | |
| CBS A114V | 114 | Pathogenic / likely pathogenic (★★) | |
| CBS R121C | 121 | Pathogenic / likely pathogenic (★★) | |
| CBS R336H | 336 | Pathogenic / likely pathogenic (★★) | |
| CBS L101P | 101 | Pathogenic / likely pathogenic (★★) | |
| CBS G116R | 116 | Pathogenic / likely pathogenic (★★) | |
| CBS R125Q | 125 | Pathogenic / likely pathogenic (★★) | |
| CBS P145L | 145 | Pathogenic / likely pathogenic (★★) | |
| CBS A155T | 155 | Pathogenic / likely pathogenic (★★) | |
| CBS C165Y | 165 | Pathogenic / likely pathogenic (★★) | |
| CBS N228S | 228 | Pathogenic / likely pathogenic (★★) | |
| CBS G259S | 259 | Pathogenic / likely pathogenic (★★) | |
| CBS G307S | 307 | Pathogenic / likely pathogenic (★★) | |
| CBS C370Y | 370 | Pathogenic / likely pathogenic (★★) | |
| CBS C109R | 109 | Pathogenic / likely pathogenic (★★) | |
| CBS I143M | 143 | Pathogenic / likely pathogenic (★★) | |
| CBS E144K | 144 | Pathogenic / likely pathogenic (★★) | |
| CBS G151R | 151 | Pathogenic / likely pathogenic (★★) | |
| CBS G153R | 153 | Pathogenic / likely pathogenic (★★) | |
| CBS T191M | 191 | Pathogenic / likely pathogenic (★★) | |
| CBS T257M | 257 | Pathogenic / likely pathogenic (★★) | |
| CBS T262M | 262 | Pathogenic / likely pathogenic (★★) | |
| CBS V371M | 371 | Pathogenic / likely pathogenic (★★) | |
| CBS D376N | 376 | Pathogenic / likely pathogenic (★★) | |
| CBS E176K | 176 | Pathogenic / likely pathogenic (★★) | |
| CBS A226T | 226 | Pathogenic / likely pathogenic (★★) | |
| CBS L136P | 136 | Pathogenic / likely pathogenic (★★) | |
| CBS A158V | 158 | Pathogenic / likely pathogenic (★★) | |
| CBS R266K | 266 | Pathogenic / likely pathogenic (★★) | |
| CBS A288T | 288 | Pathogenic / likely pathogenic (★★) | |
| CBS A331E | 331 | Pathogenic / likely pathogenic (★★) | |
| CBS G347S | 347 | Pathogenic / likely pathogenic (★★) | |
| CBS K384N | 384 | Pathogenic / likely pathogenic (★★) | |
| CBS L539S | 539 | Pathogenic / likely pathogenic (★★) | |
| CBS A183T | 183 | Pathogenic / likely pathogenic (★★) | |
| CBS D234N | 234 | Pathogenic / likely pathogenic (★★) | |
| CBS D444N | 444 | CBS | Pathogenic / likely pathogenic (★★) |
| CBS G11R | 11 | Pathogenic / likely pathogenic (★★) | |
| CBS P49L | 49 | Pathogenic / likely pathogenic (★★) | |
| CBS D129N | 129 | Pathogenic / likely pathogenic (★★) | |
| CBS V320A | 320 | Pathogenic / likely pathogenic (★★) | |
| CBS T353M | 353 | Pathogenic / likely pathogenic (★★) | |
| CBS A355P | 355 | Pathogenic / likely pathogenic (★★) | |
| CBS A288P | 288 | Pathogenic / likely pathogenic (★) | |
| CBS S217F | 217 | Pathogenic / likely pathogenic (★) |
Uncertain variants prioritized for review in Homocystinuria
| Variant | Position | Protein part | Clinical label | Evidence |
|---|---|---|---|---|
| CBS E144Q | 144 | Conflicting reports (★) | +6: 3 other pathogenic changes within 3 positions; E144K at the same position is pathogenic; not seen in the gnomAD population database; AlphaMissense 0.93 |
Same protein, different disease
- Hyperhomocysteinemia, thrombotic, cbs-related also has ClinVar records linked to CBS variants; they fall in the same places as the Homocystinuria variants (59 pathogenic / likely pathogenic).
- Classic homocystinuria also has ClinVar records linked to CBS variants; they fall partly in the same places as the Homocystinuria variants (37 pathogenic / likely pathogenic).
Diseases related to Homocystinuria
- Familial thoracic aortic aneurysm and aortic dissection, also linked to CBS
- Hyperhomocysteinemia, thrombotic, cbs-related, also linked to CBS
- Classic homocystinuria, also linked to CBS
- Connective tissue disease, also linked to CBS
- Thoracic aortic aneurysm or dissection, also linked to CBS
Frequently asked questions
Which genes have records linked to Homocystinuria?
This view contains 1 analyzed proteins: CBS. Links come from clinical records and association databases. They do not imply that every listed gene is a validated cause, and missing genes may not yet be analyzed.
What do the clinical classifications mean?
Linked records include 51 pathogenic or likely pathogenic variants, 0 variants of uncertain significance and 4 with conflicting classifications. Labels summarize source records; multi-condition records may not make a separate assertion for this disease. Check the original record and review status.
Does the evidence score change a VUS classification?
No. 1 VUS or conflicting variants reach the likely-pathogenic points range on the computable criteria available here. This is a research prioritization signal, not a clinical classification. Patient, family and other required evidence may be missing.
Can I download the variant evidence?
Download the CSV for all 61 variants in the selected disease scope, including clinical labels, review status, evidence criteria, predictor scores, functional measurements and population frequency where available.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from eligible public CATVariant analyses of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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