rs764827921

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PP2PP3_Moderate

The NM_000138.5(FBN1):c.2093C>T(p.Pro698Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,852 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P698S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

FBN1
NM_000138.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:2

Conservation

PhyloP100: 10.0

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000138.5

PP2

Missense variant where missense usually causes diseases, FBN1

PP3

MetaRNN computational evidence supports a deleterious effect, 0.912

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5 linkuse as main transcript	c.2093C>T	p.Pro698Leu	missense_variant	17/66	ENST00000316623.10
FBN1	NM_001406716.1 linkuse as main transcript	c.2093C>T	p.Pro698Leu	missense_variant	16/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10 linkuse as main transcript	c.2093C>T	p.Pro698Leu	missense_variant	17/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152194

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251364

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135838

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461658

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727118

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000504

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000809

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152194

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74342

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000386

Hom.:

Bravo

AF:

0.0000151

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 14, 2015	The p.P698L variant (also known as c.2093C>T), located in coding exon 16 of the FBN1 gene, results from a C to T substitution at nucleotide position 2093. The proline at codon 698 is replaced by leucine, an amino acid with a few similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6493 samples (12986 alleles) with coverage at this position. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Oct 12, 2023	This missense variant replaces proline with leucine at codon 698 of the FBN1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with thoracic aortic aneurysm and dissection, who showed no features of Marfan syndrome and lacked family history of Marfan syndrome (PMID: 26621581). This variant has been identified in 4/282774 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Marfan syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Nov 02, 2023

This missense variant replaces proline with leucine at codon 698 of the FBN1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with thoracic aortic aneurysm and dissection, who showed no features of Marfan syndrome and lacked family history of Marfan syndrome (PMID: 26621581). This variant has been identified in 4/282774 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Oct 26, 2020

Variant summary: FBN1 c.2093C>T (p.Pro698Leu) results in a non-conservative amino acid change located in the TB domain (IPR017878) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 251364 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.2093C>T has been reported in the literature in an individual affected with a type A dissection, ascending aortic dilatation and other risk factors (bicuspid aortic valve and hypertension). But the variant did not segregate with aortic disease (Regalado_2016). This report however, does not provide unequivocal conclusions about association of the variant with Marfan Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=3) or likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 22, 2023

Identified in a patient with Type A aortic dissection in the published literature (Regalado et al., 2015); however, this patient had other risk factors for dissection including bicuspid aortic valve and hypertension and the authors report this variant did not segregate with aortic disease; Not observed at significant frequency in large population cohorts (gnomAD); Does not affect a cysteine residue within a calcium-binding EGF-like domain or a TGF-binding protein domain of the FBN1 gene; cysteine substitutions in the calcium-binding EGF-like domains represent the majority of pathogenic missense changes associated with FBN1-related disorders (Collod-Beroud et al., 2003); 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: 12938084, 26621581) -

Acute aortic dissection;C0345050:Congenital aneurysm of ascending aorta

Benign:1

Likely benign, no assertion criteria provided

research

University of Washington Center for Mendelian Genomics, University of Washington

Jan 20, 2016

- -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 24, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.33

BayesDel_addAF

Pathogenic

0.18

BayesDel_noAF

Pathogenic

0.24

Cadd

Pathogenic

Dann

Uncertain

1.0

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.87

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.85

M_CAP

Pathogenic

0.38

MetaRNN

Pathogenic

0.91

MetaSVM

Uncertain

0.63

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.78

PROVEAN

Pathogenic

-5.7

REVEL

Pathogenic

0.69

Sift

Benign

0.22

Sift4G

Benign

0.087

Vest4

0.85

MVP

0.93

MPC

2.2

ClinPred

0.90

GERP RS

6.1

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over