Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections: genes and variants
Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections is linked to 2 analyzed proteins (FBN1 and LOX). 10 DNA variants are known to cause it; 1 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections
FBN1: Fibrillin-1
Its fibrillin-1 microfibrils provide mechanical support to elastic tissues and regulate local availability of growth factors such as TGF-beta. Pathogenic variants cause Marfan syndrome and related fibrillinopathies affecting the aorta, skeleton, eyes, skin, and lungs.
10 disease-causing and 1 uncertain variants in FBN1 are linked to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections.
LOX: Protein-lysine 6-oxidase
It oxidatively initiates covalent crosslinking of collagen and elastin, strengthening arteries and other extracellular matrices. Pathogenic loss-of-function variants can weaken the aortic wall and predispose to familial thoracic aortic aneurysm and dissection.
0 disease-causing and 0 uncertain variants in LOX are linked to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections.
Known disease-causing variants in Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| FBN1 C166Y | 166 | EGF-like 3 | Disease-causing (★★) |
| FBN1 C750Y | 750 | EGF-like 11 | Disease-causing (★★) |
| FBN1 C1672R | 1672 | EGF-like 28 | Disease-causing (★★) |
| FBN1 C1905S | 1905 | EGF-like 32 | Disease-causing (★★) |
| FBN1 C358S | 358 | TB 2 | Disease-causing (★★) |
| FBN1 C1695W | 1695 | TB 7 | Disease-causing (★★) |
| FBN1 C1818R | 1818 | EGF-like 30 | Disease-causing (★★) |
| FBN1 C2522Y | 2522 | EGF-like 43 | Disease-causing (★★) |
| FBN1 C862S | 862 | TB 4 | Disease-causing (★) |
| FBN1 C1674S | 1674 | EGF-like 28 | Disease-causing (★) |
Same protein, different disease
- Marfan syndrome is also caused by FBN1 variants; they fall mostly in different places as the Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections variants (434 disease-causing).
- Familial thoracic aortic aneurysm and aortic dissection is also caused by FBN1 variants; they fall mostly in different places as the Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections variants (406 disease-causing).
- Isolated thoracic aortic aneurysm is also caused by FBN1 variants; they fall mostly in different places as the Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections variants (12 disease-causing).
- Acromicric dysplasia is also caused by FBN1 variants; they fall mostly in different places as the Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections variants (6 disease-causing).
- Ectopia lentis 1, isolated, autosomal dominant is also caused by FBN1 variants; they fall mostly in different places as the Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections variants (6 disease-causing).
Diseases related to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections
- Familial thoracic aortic aneurysm and aortic dissection, also linked to FBN1 and LOX
- Marfan syndrome, also linked to FBN1
- Aortic aneurysm, familial thoracic 7, also linked to LOX
- Perrault syndrome, also linked to FBN1
- Connective tissue disorder, also linked to FBN1
- Familial aortopathy, also linked to FBN1
- Isolated thoracic aortic aneurysm, also linked to FBN1
- Cutis laxa, also linked to LOX
- Ectopia lentis 1, isolated, autosomal dominant, also linked to FBN1
- Acromicric dysplasia, also linked to FBN1
- Geleophysic dysplasia, also linked to FBN1
- MASS syndrome, also linked to FBN1
Frequently asked questions
Which genes are linked to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections?
In CATVariant, Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections is linked to 2 analyzed proteins: FBN1 (Fibrillin-1) and LOX (Protein-lysine 6-oxidase).
How many genetic variants are linked to Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections?
17 variants: 10 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 1 are of uncertain significance or have conflicting reports.
Which uncertain variants in Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis 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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