dbSNP rs766034866: FBN2:p.Ile1809Thr (chr5-128305945-A-G) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_001999.4(FBN2):c.5426T>C(p.Ile1809Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,482 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 Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

FBN2
NM_001999.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 9.32

Variant links:

Genes affected

FBN2 (HGNC:3604): (fibrillin 2) The protein encoded by this gene is a component of connective tissue microfibrils and may be involved in elastic fiber assembly. Mutations in this gene cause congenital contractural arachnodactyly. [provided by RefSeq, Jul 2008]

FBN2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.938

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN2	NM_001999.4 link	c.5426T>C	p.Ile1809Thr	missense_variant	Exon 43 of 65	ENST00000262464.9	NP_001990.2	P35556-1
FBN2	XM_017009228.3 link	c.5273T>C	p.Ile1758Thr	missense_variant	Exon 42 of 64		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
FBN2	ENST00000262464.9 link	c.5426T>C	p.Ile1809Thr	missense_variant	Exon 43 of 65	1	NM_001999.4	ENSP00000262464.4	P35556-1
FBN2	ENST00000703783.1 link	n.2210T>C		non_coding_transcript_exon_variant	Exon 18 of 38
FBN2	ENST00000703785.1 link	n.2129T>C		non_coding_transcript_exon_variant	Exon 17 of 27

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461308

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727006

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

AF:

0.00000657

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74340

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000283

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Sep 26, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Ile1809Thr (I1809T) ATT>ACT: c.5426 T>C in exon 43 of the FBN2 gene (NM_001999.3) The I1809T variant has not been published as a mutation or reported as a benign polymorphism to our knowledge. The I1809T variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This substitution occurs at a position that is conserved across species. Furthermore, the I1809T variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Additionally, in silico analysis predicts this variant is probably damaging to the protein structure/function. However, no missense mutations in nearby residues have been reported, indicating this region of the protein maybe tolerant of change. This variant was found in TAAD,FBN2 -

Feb 01, 2022

CeGaT Center for Human Genetics Tuebingen

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Congenital contractural arachnodactyly

Uncertain:1

Feb 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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) performed at Invitae indicates that this missense variant is expected to disrupt FBN2 protein function. ClinVar contains an entry for this variant (Variation ID: 213339). This variant has not been reported in the literature in individuals affected with FBN2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 1809 of the FBN2 protein (p.Ile1809Thr). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.62

BayesDel_addAF

Pathogenic

0.50

BayesDel_noAF

Pathogenic

0.48

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.79

D;.;D

Eigen

Pathogenic

0.80

Eigen_PC

Pathogenic

0.76

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

D;.;.

M_CAP

Pathogenic

0.40

MetaRNN

Pathogenic

0.94

D;D;D

MetaSVM

Pathogenic

0.96

MutationAssessor

Uncertain

2.6

M;.;M

PrimateAI

Pathogenic

0.87

PROVEAN

Uncertain

-4.4

D;.;D

REVEL

Pathogenic

0.93

Sift

Uncertain

0.0010

D;.;D

Polyphen

0.99

D;.;D

Vest4

0.94

MutPred

0.67

Loss of stability (P = 0.008);.;Loss of stability (P = 0.008);

MVP

0.94

MPC

0.94

ClinPred

1.0

GERP RS

5.0

Varity_R

0.62

gMVP

0.79

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