MASS syndrome: genes and variants
MASS syndrome is linked to 2 analyzed proteins (FBN1 and COL2A1). 3 DNA variants are known to cause it; 31 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 MASS syndrome
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.
2 disease-causing and 29 uncertain variants in FBN1 are linked to MASS syndrome.
COL2A1: Collagen alpha-1(II) chain
It provides the principal fibrillar collagen framework of cartilage and is also important in the vitreous and inner ear. Pathogenic variants cause a broad type II collagenopathy spectrum including Stickler syndrome, spondyloepiphyseal dysplasia, and severe skeletal dysplasias.
1 disease-causing and 2 uncertain variants in COL2A1 are linked to MASS syndrome.
Known disease-causing variants in MASS syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| FBN1 C734R | 734 | EGF-like 11 | Disease-causing (★) |
| FBN1 C2190Y | 2190 | EGF-like 37 | Disease-causing (★) |
| COL2A1 K1312N | 1312 | Fibrillar collagen NC1 | Disease-causing (★) |
Same protein, different disease
- Marfan syndrome is also caused by FBN1 variants; they fall mostly in different places as the MASS syndrome 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 MASS syndrome variants (406 disease-causing).
- Isolated thoracic aortic aneurysm is also caused by FBN1 variants; they fall mostly in different places as the MASS syndrome variants (12 disease-causing).
- Marfan syndrome/loeys-dietz syndrome/familial thoracic aortic aneurysms and dissections is also caused by FBN1 variants; they fall mostly in different places as the MASS syndrome variants (10 disease-causing).
- Acromicric dysplasia is also caused by FBN1 variants; they fall mostly in different places as the MASS syndrome variants (6 disease-causing).
- Spondyloepiphyseal dysplasia congenita is also caused by COL2A1 variants; they fall mostly in different places as the MASS syndrome variants (38 disease-causing).
- Achondrogenesis type II is also caused by COL2A1 variants; they fall mostly in different places as the MASS syndrome variants (34 disease-causing).
- Stickler syndrome is also caused by COL2A1 variants; they fall mostly in different places as the MASS syndrome variants (26 disease-causing).
- Spondyloepimetaphyseal dysplasia, Strudwick type is also caused by COL2A1 variants; they fall mostly in different places as the MASS syndrome variants (18 disease-causing).
- Connective tissue disorder is also caused by COL2A1 variants; they fall mostly in different places as the MASS syndrome variants (15 disease-causing).
Diseases related to MASS syndrome
- Connective tissue disorder, also linked to COL2A1 and FBN1
- Familial thoracic aortic aneurysm and aortic dissection, also linked to FBN1
- Marfan syndrome, also linked to FBN1
- Spondyloepiphyseal dysplasia congenita, also linked to COL2A1
- Achondrogenesis type II, also linked to COL2A1
- Perrault syndrome, also linked to FBN1
- Stickler syndrome, also linked to COL2A1
- Spondyloepimetaphyseal dysplasia, Strudwick type, also linked to COL2A1
- Familial aortopathy, also linked to FBN1
- Type 2 collagenopathy, also linked to COL2A1
- Isolated thoracic aortic aneurysm, also linked to FBN1
- Spondyloperipheral dysplasia, also linked to COL2A1
Frequently asked questions
Which genes are linked to MASS syndrome?
In CATVariant, MASS syndrome is linked to 2 analyzed proteins: FBN1 (Fibrillin-1) and COL2A1 (Collagen alpha-1(II) chain).
How many genetic variants are linked to MASS syndrome?
34 variants: 3 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 31 are of uncertain significance or have conflicting reports.
Which uncertain variants in MASS syndrome 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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