chr15-48437009-G-A

Variant names:

• chr15-48437009-G-A
• rs76702162
• NM_000138.5:c.6448C>T

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PP2 PP3 PP4 PS4 PM1 PP1_Strong

This summary comes from the ClinGen Evidence Repository: NM_000138.5 c.6448C>T is a missense variant in FBN1 predicted to cause a substitution of an arginine by cysteine at amino acid 2150 (p.Arg2150Cys). This variant has been identified in more than 15 patients with features suggestive of, or consistent with, Marfan syndrome (MFS), including at least three who meet clinical diagnostic criteria for MFS and more than 10 individuals who do not meet MFS diagnostic criteria but have thoracic aortic aneurysm and dissection (TAAD), with or without additional clinical features of MFS (PS4, PP4; Bichat, University of Tokyo, UZA, Invitae, & GeneDx internal data; PMIDs: 37042257, 19161152, 37558401, 33059708, 31730815). The variant was found to segregate with a clinical diagnosis of MFS in one patient’s parent, and with mild features suggestive of MFS or another connective tissue disorder in approximately 11 affected family members between two additional families (PP1_strong; UZA & Invitae internal data); notably, this variant is associated with particularly variable expressivity and incomplete penetrance of the MFS phenotype. It is present in gnomAD with a maximum frequency of 0.0008% (1/113462 alleles European, non-Finnish; https://gnomad.broadinstitute.org/, v2.1.1). This variant introduces a novel cysteine residue which may impede the normal formation of essential disulfide bridges (PM1). Computational prediction tools and conservation analysis support that this variant is likely to impact the protein (PP3; REVEL = 0.923). The constraint z-score for missense variants affecting FBN1 is 8.18 (PP2; gnomAD v4.0.0). In summary, this variant meets criteria to be classified as pathogenic for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: PS4, PP1_strong, PM1, PP2, PP3, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA016472/MONDO:0007947/022

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:5 U:2
• Conservation: PhyloP100: 8.02
• Publications: 7 publications found

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):

• Marfan syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet, Genomics England PanelApp
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: Unknown, AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Acromicric dysplasia

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet
• 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: Labcorp Genetics (formerly Invitae), Ambry Genetics
• 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

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM1: For more information check the summary or visit ClinGen Evidence Repository.
• PP1: For more information check the summary or visit ClinGen Evidence Repository.
• PP2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FBN1	NM_000138.5	MANE Select	c.6448C>T	p.Arg2150Cys	missense	Exon 53 of 66	NP_000129.3
	FBN1	NM_001406716.1		c.6448C>T	p.Arg2150Cys	missense	Exon 52 of 65	NP_001393645.1	P35555

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FBN1	ENST00000316623.10	TSL:1 MANE Select	c.6448C>T	p.Arg2150Cys	missense	Exon 53 of 66	ENSP00000325527.5	P35555
	FBN1	ENST00000559133.6	TSL:1	n.6448C>T		non_coding_transcript_exon	Exon 53 of 67	ENSP00000453958.2	H0YND0
	FBN1	ENST00000537463.6	TSL:5	n.*2211C>T		non_coding_transcript_exon	Exon 28 of 31	ENSP00000440294.2	F6U495

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152100 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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

GnomAD2 exomes AF: 0.00000797 AC: 2 AN: 251026 AF XY: 0.00000737

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: 0.0000462

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74426

African (AFR) AF: 0.00 AC: 0 AN: 41556

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4816

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10594

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67996

Other (OTH) AF: 0.00 AC: 0 AN: 2112

Alfa AF: 0.00 Hom.: 0

ExAC AF: 0.0000165 AC: 2

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
1	1	-	Familial thoracic aortic aneurysm and aortic dissection (2)
2	-	-	Marfan syndrome (2)
1	1	-	not provided (2)
1	-	-	Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	33
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.64	D
PhyloP100		8.0
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-7.1	D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0060	D
Vest4		0.89
MVP		0.98
MPC		1.7
ClinPred		1.0	D
GERP RS		5.8
Mutation Taster		=1/99	disease causing

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

Other links and lift over

dbSNP: rs76702162; hg19: chr15-48729206; COSMIC: COSV57312375; COSMIC: COSV57312375;