rs774003646

Positions:

chr15-48485397-A-G

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP2BS4

This summary comes from the ClinGen Evidence Repository: NM_00138 c.3689T>C is a missense variant in FBN1 predicted to cause a substitution of a Methionine by Threonine at amino acid 1230 p.(Met1230Thr). This variant was identified in an internal proband with ectopia lentis and thoracic aortic aneurysm and dissection, however a pathogenic frameshift variant in FBN1 was also identified in the proband (BP2) and was considered to explain the phenotype. Furthermore this variant does not segregate with disease in an affected family member (BS4). . This variant has been previously reported in ClinVar as of uncertain significance (Variation ID: 263789). This variant has been identified in 0.0018% of individuals of European origin (https://gnomad.broadinstitute.org/). Computational prediction tools and conservation analysis are unclear on the predicted impact on the protein. The constraint z-score for missense variants affecting FBN1 is 5.06 however due to the presence of one benign argument PP2 cannot be used . In summary, this variant meets criteria to be classified as likely benign for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: BS4, BP2 LINK:https://erepo.genome.network/evrepo/ui/classification/CA051349/MONDO:0007947/022

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

FBN1
NM_000138.5 missense

Scores

Clinical Significance

Likely benign reviewed by expert panel U:3B:2

Conservation

PhyloP100: 9.32

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 Likely_benign. Variant got -5 ACMG points.

BP2

For more information check the summary or visit ClinGen Evidence Repository.

BS4

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5 linkuse as main transcript	c.3689T>C	p.Met1230Thr	missense_variant	30/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1 linkuse as main transcript	c.3689T>C	p.Met1230Thr	missense_variant	29/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10 linkuse as main transcript	c.3689T>C	p.Met1230Thr	missense_variant	30/66	1	NM_000138.5	ENSP00000325527	P1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251480

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461878

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727244

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000468

Hom.:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Likely benign

Submissions summary: Uncertain:3Benign:2

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 26, 2017	The p.M1230T variant (also known as c.3689T>C), located in coding exon 29 of the FBN1 gene, results from a T to C substitution at nucleotide position 3689. The methionine at codon 1230 is replaced by threonine, an amino acid with some similar properties. This amino acid position is well 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 alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 16, 2023	This missense variant replaces methionine with threonine at codon 1230 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 not been reported in individuals affected with FBN1-related disorders in the literature. This variant has been identified in 2/251480 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;C4707243:Familial thoracic aortic aneurysm and aortic dissection

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 20, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on FBN1 protein function. ClinVar contains an entry for this variant (Variation ID: 263789). This variant has not been reported in the literature in individuals affected with FBN1-related conditions. This variant is present in population databases (rs774003646, gnomAD 0.002%). This sequence change replaces methionine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 1230 of the FBN1 protein (p.Met1230Thr). -

Marfan syndrome

Benign:1

Likely benign, reviewed by expert panel

curation

ClinGen FBN1 Variant Curation Expert Panel, ClinGen

Dec 01, 2022

NM_00138 c.3689T>C is a missense variant in FBN1 predicted to cause a substitution of a Methionine by Threonine at amino acid 1230 p.(Met1230Thr). This variant was identified in an internal proband with ectopia lentis and thoracic aortic aneurysm and dissection, however a pathogenic frameshift variant in FBN1 was also identified in the proband (BP2) and was considered to explain the phenotype. Furthermore this variant does not segregate with disease in an affected family member (BS4). . This variant has been previously reported in ClinVar as of uncertain significance (Variation ID: 263789). This variant has been identified in 0.0018% of individuals of European origin (https://gnomad.broadinstitute.org/). Computational prediction tools and conservation analysis are unclear on the predicted impact on the protein. The constraint z-score for missense variants affecting FBN1 is 5.06 however due to the presence of one benign argument PP2 cannot be used . In summary, this variant meets criteria to be classified as likely benign for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: BS4, BP2 -

FBN1-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

May 03, 2024

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.58

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.25

CADD

Uncertain

DANN

Uncertain

0.99

Eigen

Uncertain

0.19

Eigen_PC

Uncertain

0.39

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Benign

0.77

M_CAP

Uncertain

0.17

MetaRNN

Uncertain

0.68

MetaSVM

Uncertain

0.28

MutationTaster

Benign

1.0

PrimateAI

Pathogenic

0.85

PROVEAN

Uncertain

-4.0

REVEL

Uncertain

0.60

Sift

Benign

0.15

Sift4G

Benign

0.49

Vest4

0.83

MutPred

0.43

Gain of phosphorylation at M1230 (P = 0.0187);

MVP

0.84

MPC

1.2

ClinPred

0.75

GERP RS

6.0

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

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