Thoracic aortic aneurysm or dissection (GMS)

Gene: FBN1

Green List (high evidence)

Comment on mode of inheritance: There are numerous individuals with Marfan syndrome reported with both heterozygous and biallelic FBN1 variants - though biallelic cases are known to present with more severe features, and with higher disease penetrance. Hence, the MOI on Thoracic aortic aneurysm or dissection (GMS) should be changed from MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted to BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal.

Created: 22 May 2026, 2:33 p.m. | Last Modified: 22 May 2026, 2:33 p.m.

Panel Version: 5.4

PMID: 23278365 Hogue et al., 2013
Report of a proband (Mexican-American woman, consanguineous parents) + literature review of 4 additional unrelated families with biallelic FBN1 variants and severe Marfan syndrome - heterozygous parents were either asymptomatic or had a milder form of Marfan syndrome. Mostly biallelic missense, one instance of missense + deletion in 2 sibs. Proband presented with scoliosis, arachnodactyly, dislocated lenses, mitral valve prolapse, aortic dilatation, dural ectasias.

PMID: 27582083 Arnaud et al., 2017
In a large cohort of Marfan syndrome patients, 4 probands were homozygous and 22 potentially comp het for FBN1 variants (5 confirmed to be in trans). All 4 homozygous individuals harboured missense variants; comp het cases either had biallelic missense FBN1 variants, or missense + nonsense. Heterozygous carriers usually also diagnosed with MFS, sometimes very mild e.g., isolated mild skeletal features in women. The severity of symptoms and age of onset varied a lot, both between biallelic and among monoallelic cases.

PMID: 31950671 McInerney-Leo et al., 2020
Report of a pedigree with Marfan syndrome (ectopia lentis, though the skeletal phenotype is variable, and not all have aortic dilatation) - some individuals with monoallelic and some with biallelic FBN1 variants.
All subjects with Marfan syndrome harboured p.Tyr754Cys in FBN1. An additional variant (p.Met2273Thr), previously associated with 'incomplete' MFS, was identified in three siblings. These three compound heterozygous individuals had aortic dilatation at early age (all <30 years): one also had cerebral and ocular aneurysms; and one, who had undergone surgical repair aged 18 years, died from aortic dissection at 31 years.
The heterozygous father (p.Tyr754Cys) with MFS died at 57 years (myocardial infarction) without requiring surgical intervention and one heterozygous (p.Tyr754Cys) sibling has aortic dilatation presenting >40 years but not requiring surgical intervention. Another heterozygous (p.Tyr754Cys) sibling did require aortic root repair (28 years). The heterozygous (p.Met2273Thr) mother had aortic dilatation diagnosed at age 68 years but has not required surgical repair.

The association between FBN1 and Marfan syndrome is rated as Definitive in Gene2Phenotype, both for the AD and AR inheritance patterns.

Created: 22 May 2026, 2:29 p.m. | Last Modified: 22 May 2026, 2:30 p.m.

Panel Version: 5.3

Mode of inheritance
BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal

Phenotypes
Marfan syndrome, OMIM:154700; Marfan syndrome, MONDO:0007947

Publications

• 23278365
• 27582083
• 31950671

Green List (high evidence)

Submitted on behalf of the GMS Cardiology specialist group. The group has agreed that this gene should be Green on this panel.

Created: 18 Nov 2019, 4:33 p.m. | Last Modified: 18 Nov 2019, 4:33 p.m.

Panel Version: 0.35

Green List (high evidence)

On CGGL Royal Brompton panel. Multiple pathogenic variants reported. Cardinal gene for Marfan syndrome.

Created: 18 Sep 2019, 2:15 p.m. | Last Modified: 18 Sep 2019, 2:15 p.m.

Panel Version: 0.30

Phenotypes
Marfan syndrome

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Well characterised gene (Marfan syndrome / aortopathy); present on Wessex aortopathy and TAAD panels.

Created: 29 Aug 2019, 2:31 p.m. | Last Modified: 29 Aug 2019, 2:31 p.m.

Panel Version: 0.5

Phenotypes
Marfan syndrome; Ectopia lentis

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

154700 Marfan syndrome; well characterised gene

Created: 25 Mar 2019, 4:30 p.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Gene currently tested on Manchester cardiac gene panel. 2721 variants listed on HGMD (accessed 29/01/2019). ClinGen Knowledge Base: definitive association with TAAD (accessed 29/01/2019).

Created: 14 Feb 2019, 1:38 p.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Acromicric dysplasia (102370); Ectopia lentis, familial (129600); Geleophysic dysplasia 2 (614185); Marfan lipodystrophy syndrome (616914); Marfan syndrome (154700); MASS syndrome (604308); Stiff skin syndrome (184900); Weill-Marchesani syndrome 2, dominant, (608328)

Publications

• 20082464

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Green List (high evidence)

I don't know

This gene was part of an initial gene list collated by Matthew Edwards Royal Brompton Hospital sent 16th Jan 2019 on behalf of the London South GLH for review by the GMS Cardiology Specialist Group. Only gene symbol from the Royal Brompton gene panel was provided - suggested initial gene rating and evidence for inclusion not provided with the list.

Created: 20 Feb 2019, 2:17 p.m.

On the Inherited Cardiac Condition Genes panel reported in: Development of a Comprehensive Sequencing Assay for Inherited Cardiac Condition Genes, Pua et al, Journal of Cardiovascular Translational Research, online Feb 2016 (doi:10.​1007/​s12265-016-9673-5). The panel contains disease-causing, putatively pathogenic, research and phenocopy genes, and it is unclear from the publication whether this gene falls into the disease-causing category. No. of mutations indicated in supplemental table = 24.

Created: 19 Feb 2016, 10:48 a.m.

Publications

• 7762551
• doi:10.​1007/​s12265-016-9673-5

Green List (high evidence)

Mutations in exons 24-32 are associated with a more severe phenotype, often manifesting in the neonatal period.
Mutations in exons 41 and 42 also cause Acromicric dysplasia and Geleophysic dysplasia.

Created: 20 Jan 2016, 4:48 p.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Marfan syndrome; tall; Arachnodactyly; scoliosis; Aortic root dilatation; Aortic dissection; Pectus excavatum; hypermobile joints; pes planus; ectopia lentis