Genetic Variant NM_000138.5:c.494G>A (chr15-48596327-C-T) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM5PP2PP3_ModeratePP5

The NM_000138.5(FBN1):c.494G>A(p.Arg165Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000806 in 1,613,896 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R165P) has been classified as Likely pathogenic.

Frequency

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

Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

FBN1
NM_000138.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:2

Conservation

PhyloP100: 7.57

Publications

7 publications found

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 Gene-Disease associations (from GenCC):

familial thoracic aortic aneurysm and aortic dissection
Inheritance: AD, Unknown Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
Marfan syndrome
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, ClinGen, Orphanet, G2P, Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
Acromicric dysplasia
Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics
progeroid and marfanoid aspect-lipodystrophy syndrome
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae)
stiff skin syndrome
Inheritance: AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
Weill-Marchesani syndrome 2, dominant
Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
geleophysic dysplasia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
isolated ectopia lentis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
neonatal Marfan syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Weill-Marchesani syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
ectopia lentis 1, isolated, autosomal dominant
Inheritance: AD Classification: LIMITED Submitted by: G2P
Shprintzen-Goldberg syndrome
Inheritance: Unknown, AD Classification: LIMITED, NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae), ClinGen

FBN1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM1

In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000138.5

PM5

Other missense variant is known to change same aminoacid residue: Variant chr15-48596327-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 406352.

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 Marfan syndrome, Weill-Marchesani syndrome 2, dominant, progeroid and marfanoid aspect-lipodystrophy syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, stiff skin syndrome, familial thoracic aortic aneurysm and aortic dissection, isolated ectopia lentis, ectopia lentis 1, isolated, autosomal dominant, Acromicric dysplasia, neonatal Marfan syndrome, Weill-Marchesani syndrome.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.855

PP5

Variant 15-48596327-C-T is Pathogenic according to our data. Variant chr15-48596327-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 807252.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000138.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
FBN1	NM_000138.5	MANE Select	c.494G>A	p.Arg165Gln	missense	Exon 6 of 66	NP_000129.3
FBN1	NM_001406716.1		c.494G>A	p.Arg165Gln	missense	Exon 5 of 65	NP_001393645.1
FBN1	NM_001406717.1		c.494G>A	p.Arg165Gln	missense	Exon 6 of 9	NP_001393646.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
FBN1	ENST00000316623.10	TSL:1 MANE Select	c.494G>A	p.Arg165Gln	missense	Exon 6 of 66	ENSP00000325527.5
FBN1	ENST00000559133.6	TSL:1	n.494G>A		non_coding_transcript_exon	Exon 6 of 67	ENSP00000453958.2
FBN1	ENST00000537463.6	TSL:5	n.494G>A		non_coding_transcript_exon	Exon 6 of 31	ENSP00000440294.2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152168

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

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251384

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS 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:

0.00000821

AC:

AN:

1461728

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727166

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33470

American (AMR)

AF:

0.0000447

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000899

AC:

AN:

1111882

Other (OTH)

AF:

0.00

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

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

AF:

0.00000657

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74338

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41430

American (AMR)

AF:

0.0000654

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

ClinVar submissions as Germline

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Familial thoracic aortic aneurysm and aortic dissection (1)

Marfan syndrome (1)

Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.35

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Pathogenic

0.18

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

Eigen

Pathogenic

0.70

Eigen_PC

Pathogenic

0.74

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.89

M_CAP

Uncertain

0.18

MetaRNN

Pathogenic

0.86

MetaSVM

Uncertain

0.70

PhyloP100

7.6

PrimateAI

Uncertain

0.71

PROVEAN

Uncertain

-3.2

REVEL

Uncertain

0.63

Sift

Uncertain

0.0040

Sift4G

Uncertain

0.051

Vest4

0.74

MutPred

0.51

Loss of catalytic residue at N164 (P = 0.2849)

MVP

0.95

MPC

1.6

ClinPred

0.82

GERP RS

5.9

Mutation Taster

=33/67

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over