rs193922245

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 1P and 6B. PP2BP4_ModerateBS2

The NM_000138.5(FBN1):c.83A>G(p.Asn28Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000855 in 1,614,070 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/17 in silico tools predict a benign 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. N28D) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000090 ( 0 hom. )

Consequence

FBN1
NM_000138.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 1.70

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.

PP2

Missense variant where missense usually causes diseases, FBN1

BP4

Computational evidence support a benign effect (MetaRNN=0.10846728).

BS2

High AC in GnomAd at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
FBN1	NM_000138.5 linkuse as main transcript	c.83A>G	p.Asn28Ser	missense_variant	2/66	ENST00000316623.10
FBN1	NM_001406716.1 linkuse as main transcript	c.83A>G	p.Asn28Ser	missense_variant	1/65
FBN1	NM_001406717.1 linkuse as main transcript	c.83A>G	p.Asn28Ser	missense_variant	2/9
FBN1	NM_001406718.1 linkuse as main transcript	c.83A>G	p.Asn28Ser	missense_variant	2/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10 linkuse as main transcript	c.83A>G	p.Asn28Ser	missense_variant	2/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152194

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000723

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

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:

0.0000477

AC:

AN:

251478

Hom.:

AF XY:

0.0000441

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000791

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000896

AC:

131

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000756

AC XY:

AN XY:

727236

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.0000671

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:

0.000112

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152194

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74356

show subpopulations

Gnomad4 AFR

AF:

0.0000723

Gnomad4 AMR

AF:

0.000196

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000584

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000659

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1

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	Color Diagnostics, LLC DBA Color Health	Nov 18, 2022	This missense variant replaces asparagine with serine at codon 28 of the FBN1 protein. Computational prediction tool suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 13/282862 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 22, 2019	The p.N28S variant (also known as c.83A>G), located in coding exon 1 of the FBN1 gene, results from an A to G substitution at nucleotide position 83. The asparagine at codon 28 is replaced by serine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species; however, serine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Marfan syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jan 11, 2024

This missense variant replaces asparagine with serine at codon 28 of the FBN1 protein. Computational prediction tool suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <=0.5, PMID: 27666373). To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 13/282862 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

Jun 29, 2017

Variant summary: The FBN1 c.83A>G (p.Asn28Ser) variant involves the alteration of a conserved nucleotide. 4/4 in silico tools predict a benign outcome for this variant. This variant was found in 8/121390 control chromosomes at a frequency of 0.0000659, which does not exceed the estimated maximal expected allele frequency of a pathogenic FBN1 variant (0.0001125). This variant has been reported in one MFS patient and one patient with sudden death without strong evidence supporting causality. However, no functional studies supporting a pathogenic outcome have been reported and its unequivocal co-segregation with disease in individuals/families with Marfan has not been demonstrated at this time. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as VUS. Taken together, this variant is classified as VUS. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 19, 2022

Has been previously reported in a 36 year-old female with sudden unexplained death who also harbored a second cardiogenetic variant in the PKP2 gene (Sanchez et al., 2016).; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Does not affect a cysteine residue within a calcium-binding EGF-like 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).; This variant is associated with the following publications: (PMID: 27930701, 27906200) -

Marfan syndrome;C0265287:Acromicric dysplasia;C1858556:MASS syndrome;C1861456:Stiff skin syndrome;C1869115:Weill-Marchesani syndrome 2, dominant;C3280054:Geleophysic dysplasia 2;C3541518:Ectopia lentis 1, isolated, autosomal dominant;C4310796:Progeroid and marfanoid aspect-lipodystrophy syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Jul 27, 2021

- -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 19, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.062

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.35

Cadd

Benign

Dann

Benign

0.82

Eigen

Benign

-0.47

Eigen_PC

Benign

-0.26

FATHMM_MKL

Benign

0.49

LIST_S2

Uncertain

0.88

D;D

M_CAP

Benign

0.054

MetaRNN

Benign

0.11

T;T

MetaSVM

Benign

-0.96

MutationTaster

Benign

0.99

N;N

PrimateAI

Uncertain

0.52

PROVEAN

Benign

-0.40

N;D

REVEL

Benign

0.060

Sift

Benign

0.87

T;D

Sift4G

Benign

0.84

T;T

Vest4

0.23

MutPred

0.37

Gain of glycosylation at N28 (P = 0.035);Gain of glycosylation at N28 (P = 0.035);

MVP

0.60

MPC

0.42

ClinPred

0.034

GERP RS

3.8

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