rs794728283

Variant names:

• chr15-48415549-G-A
• rs794728283
• NM_000138.5:c.8038C>T

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000138.5(FBN1):​c.8038C>T​(p.Arg2680Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,138 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R2680H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 1.72
• Publications: 7 publications found

Genes affected

FBN1 (HGNC:3603): (fibrillin 1) This gene encodes a member of the fibrillin family of proteins. The encoded preproprotein is proteolytically processed to generate two proteins including the extracellular matrix component fibrillin-1 and the protein hormone asprosin. Fibrillin-1 is an extracellular matrix glycoprotein that serves as a structural component of calcium-binding microfibrils. These microfibrils provide force-bearing structural support in elastic and nonelastic connective tissue throughout the body. Asprosin, secreted by white adipose tissue, has been shown to regulate glucose homeostasis. Mutations in this gene are associated with Marfan syndrome and the related MASS phenotype, as well as ectopia lentis syndrome, Weill-Marchesani syndrome, Shprintzen-Goldberg syndrome and neonatal progeroid syndrome. [provided by RefSeq, Apr 2016]

FBN1 Gene-Disease associations (from GenCC):

• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Marfan syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P, PanelApp Australia, Orphanet, Ambry Genetics
• Acromicric dysplasia

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics
• progeroid and marfanoid aspect-lipodystrophy syndrome

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• stiff skin syndrome

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• Weill-Marchesani syndrome 2, dominant

  Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• geleophysic dysplasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• isolated ectopia lentis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• neonatal Marfan syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Weill-Marchesani syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• ectopia lentis 1, isolated, autosomal dominant

  Inheritance: AD Classification: LIMITED Submitted by: G2P
• Shprintzen-Goldberg syndrome

  Inheritance: AD, Unknown Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 19 ACMG points.

• PM1: In a hotspot region, there are 16 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-48415548-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 527153.
• PP2: Missense variant in the FBN1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 1311 curated pathogenic missense variants (we use a threshold of 10). The gene has 112 curated benign missense variants. Gene score misZ: 5.0644 (above the threshold of 3.09). Trascript score misZ: 8.1787 (above the threshold of 3.09). GenCC associations: The gene is linked to Marfan syndrome, Weill-Marchesani syndrome 2, dominant, progeroid and marfanoid aspect-lipodystrophy syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, stiff skin syndrome, familial thoracic aortic aneurysm and aortic dissection, isolated ectopia lentis, ectopia lentis 1, isolated, autosomal dominant, Acromicric dysplasia, neonatal Marfan syndrome, Weill-Marchesani syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.976
• PP5: Variant 15-48415549-G-A is Pathogenic according to our data. Variant chr15-48415549-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 200127.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.8038C>T	p.Arg2680Cys	missense_variant	Exon 64 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.8038C>T	p.Arg2680Cys	missense_variant	Exon 63 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.8038C>T	p.Arg2680Cys	missense_variant	Exon 64 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461138 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726920

African (AFR) AF: 0.00 AC: 0 AN: 33458

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86234

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111340

Other (OTH) AF: 0.00 AC: 0 AN: 60368

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Marfan syndrome Pathogenic:3

Nov 01, 2016

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 07, 2017

Center for Medical Genetics Ghent, University of Ghent

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 10, 2023

deCODE genetics, Amgen

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: case-control

The p.(Arg2680Cys) variant was identified in a six-generation Marfan syndrome family in Iceland. There are 21 carriers of the variant in this family, either diagnosed with Marfan syndrome and/or show clinical features consistent with Marfan syndrome. Overall p.(Arg2680Cys) appears to result in mild Marfan syndrome, but a strong predisposition to the development of abdominal aortic aneurysms. The variant associates with increased height (p-value 5.65*10-8; SD 1.46) and thoracid aortic aneurysm (p-value 0.042; OR 23.3). Applied ACMG criteria: PS4, PM2, PP2, PP4Applied ACMG criteria: PS4, PM2, PP2, PP3, PP4, PP5_strong -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:2

Dec 18, 2018

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R2680C variant (also known as c.8038C>T), located in coding exon 63 of the FBN1 gene, results from a C to T substitution at nucleotide position 8038. The arginine at codon 2680 is replaced by cysteine, an amino acid with highly dissimilar properties, and is located in the cbEGF-like #43 domain. This variant has been reported in individuals with Marfan syndrome-like features, including ocular and skeletal findings and one reportedly de novo occurrence (Palz M et al. Am. J. Med. Genet., 2000 Mar;91:212-21; Comeglio P et al. Hum. Mutat., 2007 Sep;28:928). This variant was also described in an individual with Marfan syndrome who was a compound heterozygote with an additional FBN1 variant; her son was heterozygous for only p.R2680C and was reported to have ectopia lentis at two years old, with no additional clinical features of Marfan syndrome at that time (Arnaud P et al. J. Med. Genet., 2017 02;54:100-103). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. The majority of FBN1 mutations identified to date have involved the substitution or generation of cysteine residues within cbEGF domains (Vollbrandt T et al. J Biol Chem. 2004;279(31):32924-32931). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Sep 05, 2018

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Marfan Syndrome/Loeys-Dietz Syndrome/Familial Thoracic Aortic Aneurysms and Dissections Pathogenic:1

Jan 29, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: FBN1 c.8038C>T (p.Arg2680Cys) results in a non-conservative amino acid change located in the EGF like domain (IPR001881) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 249484 control chromosomes (gnomAD). c.8038C>T has been reported in the literature in multiple individuals affected with Marfan Syndrome (examples: Collod-Beroud_1998, Palz_2000, and Klemenzdottir_2024). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 37684520, 9399842, 10756346). ClinVar contains an entry for this variant (Variation ID: 200127). Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:1

Aug 04, 2025

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported in the literature in association with Marfan syndrome or suspected Marfan syndrome in multiple individuals, several of whom had ectopia lentis and skeletal features without aortic dilation, and in patients referred for genetic testing at GeneDx (PMID: 17657824, 17679947, 27582083, 37684520); Identified as a de novo variant with confirmed parentage in a patient referred for genetic testing at GeneDx with clinical features of Marfan syndrome and as an apparently de novo variant in a patient in the published literature with tall stature, scoliosis, pectus excavatum, ectopia lentis, hypermobility, and mitral valve prolapse (PMID: 10756346); Introduces a new cysteine residue within an EGF-like domain of the FBN1 gene, which may affect disulfide bonding and is predicted to alter the structure and function of the protein; cysteine substitutions in the EGF-like domains represent the majority of pathogenic missense changes associated with FBN1-related disorders (PMID: 12938084); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 17568394, 8653794, 9401003, 18615205, 15054843, 17657824, 27647783, 27582083, 17679947, 33059708, 31751304, 37937776, 37684520, 12938084, 10756346) -

Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Jul 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 2680 of the FBN1 protein (p.Arg2680Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with FBN1-related conditions and Marfan syndrome (PMID: 10756346, 12938084, 17657824, 27582083; Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 200127). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt FBN1 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Pathogenic	31
DANN	Pathogenic	1.0
Eigen	Uncertain	0.43
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.57	D
PhyloP100		1.7
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Vest4		0.98
MutPred		0.86		Gain of disorder (P = 0.268);
MVP		0.99
MPC		1.7
ClinPred		1.0	D
GERP RS		2.5
Mutation Taster		=15/85	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs794728283; hg19: chr15-48707746; COSMIC: COSV100355798;