Genetic Variant FBN2:p.Asn1402Lys (chr5-128332928-G-C) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM2

The NM_001999.4(FBN2):c.4206C>G(p.Asn1402Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,620 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. N1402N) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

FBN2
NM_001999.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.785

Publications

5 publications found

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 Gene-Disease associations (from GenCC):

congenital contractural arachnodactyly
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
carpal tunnel syndrome
Inheritance: AD Classification: LIMITED Submitted by: Franklin by Genoox
familial thoracic aortic aneurysm and aortic dissection
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
macular degeneration, early-onset
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

FBN2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 10 uncertain in NM_001999.4

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN2	NM_001999.4 link	c.4206C>G	p.Asn1402Lys	missense_variant	Exon 32 of 65	ENST00000262464.9	NP_001990.2
FBN2	XM_017009228.3 link	c.4053C>G	p.Asn1351Lys	missense_variant	Exon 31 of 64		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN2	ENST00000262464.9 link	c.4206C>G	p.Asn1402Lys	missense_variant	Exon 32 of 65	1	NM_001999.4	ENSP00000262464.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251378

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461620

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727128

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33458

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39684

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111818

Other (OTH)

AF:

0.00

AC:

AN:

60384

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.37

BayesDel_addAF

Uncertain

0.029

BayesDel_noAF

Benign

-0.20

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.68

D;.;D;D;T

Eigen

Benign

0.014

Eigen_PC

Benign

-0.042

FATHMM_MKL

Uncertain

0.89

LIST_S2

Uncertain

0.89

D;.;.;D;D

M_CAP

Uncertain

0.17

MetaRNN

Uncertain

0.50

D;D;D;D;D

MetaSVM

Uncertain

0.040

MutationAssessor

Uncertain

2.4

M;.;M;.;.

PhyloP100

0.79

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-3.4

D;.;D;D;D

REVEL

Uncertain

0.56

Sift

Uncertain

0.0090

D;.;D;D;D

Sift4G

Uncertain

0.011

.;.;.;D;D

Polyphen

0.90

P;.;P;.;P

Vest4

0.52

MutPred

0.58

Gain of methylation at N1402 (P = 0.0102);.;Gain of methylation at N1402 (P = 0.0102);.;.;

MVP

0.68

MPC

0.62

ClinPred

0.94

GERP RS

1.1

Varity_R

0.28

gMVP

0.89

Mutation Taster

=8/92

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over