15-48437347-G-C

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM2PP2PP3_ModeratePP5_Very_Strong

The NM_000138.5(FBN1):​c.6354C>G​(p.Ile2118Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. I2118I) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Consequence

FBN1
NM_000138.5 missense

Scores

2
6
9

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: -0.700
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]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 13 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
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 MASS syndrome, Weill-Marchesani syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, Acromicric dysplasia, familial thoracic aortic aneurysm and aortic dissection, progeroid and marfanoid aspect-lipodystrophy syndrome, ectopia lentis 1, isolated, autosomal dominant, Marfan syndrome, Weill-Marchesani syndrome 2, dominant, isolated ectopia lentis, neonatal Marfan syndrome, stiff skin syndrome.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.919
PP5
Variant 15-48437347-G-C is Pathogenic according to our data. Variant chr15-48437347-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 180039.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
FBN1NM_000138.5 linkc.6354C>G p.Ile2118Met missense_variant Exon 52 of 66 ENST00000316623.10 NP_000129.3 P35555
FBN1NM_001406716.1 linkc.6354C>G p.Ile2118Met missense_variant Exon 51 of 65 NP_001393645.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
FBN1ENST00000316623.10 linkc.6354C>G p.Ile2118Met missense_variant Exon 52 of 66 1 NM_000138.5 ENSP00000325527.5 P35555

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
Cov.:
31
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Marfan syndrome Pathogenic:1
Nov 17, 2014
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The p.Ile2118Met variant in FBN1 has been reported in 1 individual with Marfan s yndrome (Comeglio 2007) and has been identified as a de novo occurrence by our l aboratory in 1 individual with Marfan syndrome. It was absent from large populat ion studies. Computational prediction tools and conservation analysis do not pro vide strong support for or against an impact to the protein. Additionally, anoth er variant affecting the same nucleotide (p.Ile2118Ile) has been shown to lead t o skipping of exon 51 (Liu 1997), suggesting changes to this nucleotide position may not be tolerated. In summary, although additional studies are required to f ully establish its clinical significance, the p.Ile2118Met variant is likely pat hogenic. -

Marfan Syndrome/Loeys-Dietz Syndrome/Familial Thoracic Aortic Aneurysms and Dissections Pathogenic:1
Nov 21, 2017
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: The FBN1 c.6354C>G (p.Ile2118Met) variant involves the alteration of a non-conserved nucleotide and 3/3 in silico tools predict a benign outcome for this variant (SNPsandGO and MutationTaster not captured due to low reliability index and p-value, respectively). This variant is absent in 276492 control chromosomes (publication controls and gnomAD). The variant has been reported in 1 individual with Marfan syndrome (Comeglio 2007) and described in ClinVar in a patient with Marfan syndrome as a de novo event. Another variant affecting the same nucleotide, c.6354C>T (p.Ile2118Ile - scored DV by LCA) has been reported and found to cause skipping of exon 52 (PMID: 9241263), 3/5 splicing prediction tools for the variant of interest do predict an impact on splicing. However, these predictions have not been functionally assessed. In addition, a clinical diagnostic laboratory has classified the variant as "likely pathogenic." Taken together, this variant is classified as likely pathogenic. -

Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1
Oct 03, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 2118 of the FBN1 protein (p.Ile2118Met). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with Marfan syndrome (PMID: 17657824; Invitae). ClinVar contains an entry for this variant (Variation ID: 180039). 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 not expected to disrupt FBN1 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.11
BayesDel_addAF
Pathogenic
0.17
D
BayesDel_noAF
Uncertain
0.0
CADD
Benign
16
DANN
Uncertain
1.0
Eigen
Benign
-0.32
Eigen_PC
Benign
-0.34
FATHMM_MKL
Benign
0.23
N
LIST_S2
Uncertain
0.94
D
M_CAP
Uncertain
0.10
D
MetaRNN
Pathogenic
0.92
D
MetaSVM
Benign
-0.54
T
PrimateAI
Uncertain
0.68
T
PROVEAN
Benign
-0.84
N
REVEL
Uncertain
0.56
Sift
Benign
0.18
T
Sift4G
Benign
0.13
T
Vest4
0.70
MutPred
0.81
Gain of disorder (P = 0.0362);
MVP
0.98
MPC
0.66
ClinPred
0.54
D
GERP RS
-1.5

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.22
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.22
Position offset: -25

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.

Other links and lift over

dbSNP: rs112989722; hg19: chr15-48729544; API