15-48485374-C-T

Variant names:

• chr15-48485374-C-T
• rs794728208
• NM_000138.5:c.3712G>A

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PP4 PP2 PP3 PM2_Supporting PS4 PM1 PM5 PP1_Moderate

This summary comes from the ClinGen Evidence Repository: The NM_00138 c.3712G>A is a missense variant in FBN1 predicted to cause a substitution of an aspartic acid by asparagine at amino acid 1238 (p.Asp1238Asn). This variant impacts the first aspartic acid within a calcium-binding (cb) (D/N)-X-(D/N)-(E/Q)-Xm-(D/N)-Xn-(Y/F) consensus sequence of a cbEGF-like domain (PM1). This variant was found in a proband with a clinical diagnosis of Marfan syndrome (MFS) (Internal lab data, PP4). This variant has been reported 12 times in ClinVar: three times as pathogenic, eight times as likely pathogenic, and once as uncertain significance (Variation ID: 200022). This variant has also been reported in multiple individuals with a clinical diagnosis of MFS, ectopia lentis and/or clinical features of MFS (PS4_Strong; PMID 32730690, 10533071, 30675029, internal lab data). This variant was found to segregate with disease in at least four affected relatives with MFS from four families (PMID 32730690, internal lab data; PP1_Mod). This variant is not present in gnomAD (PM2_sup; https://gnomad.broadinstitute.org/ v2.1.1). A different missense variant at this position, c.3713A>G (p.Asp1238Gly), has previously been previously established as (likely) pathogenic and was reported an individual with a clinical diagnosis of MFS (PM5; PMID 11175294). Computational prediction tools and conservation analysis suggest that this variant may impact the protein (REVEL: 0.895). This variant is located in the last nucleotide of the exon. In silico prediction programs suggest a possibly impact on splicing, however RNA analysis using patient blood showed no impact for this variant on RNA splicing (PMID 32123317). The constraint z-score for missense variants affecting FBN1 is 5.06 (PP2). 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_Strong, PM1, PM5, PP1_Mod, PM2_Sup, PP2, PP3, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA014476/MONDO:0007947/022

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FBN1 NM_000138.5 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:14 U:1
• Conservation: PhyloP100: 7.90
• Publications: 5 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

Specifications for FBN1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Pathogenic. The variant received 14 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.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM5: 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.3712G>A	p.Asp1238Asn	missense splice_region	Exon 30 of 66	NP_000129.3
	FBN1	NM_001406716.1		c.3712G>A	p.Asp1238Asn	missense splice_region	Exon 29 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.3712G>A	p.Asp1238Asn	missense splice_region	Exon 30 of 66	ENSP00000325527.5	P35555
	FBN1	ENST00000559133.6	TSL:1	n.3712G>A		splice_region non_coding_transcript_exon	Exon 30 of 67	ENSP00000453958.2	H0YND0
	FBN1	ENST00000674301.2		n.3712G>A		splice_region non_coding_transcript_exon	Exon 30 of 68	ENSP00000501333.2	A0A6I8PL22

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461856 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111992

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
5	-	-	Marfan syndrome (5)
3	-	-	Familial thoracic aortic aneurysm and aortic dissection (3)
3	-	-	not provided (3)
1	-	-	Cardiovascular phenotype (1)
1	-	-	Marfan syndrome;C0265287:Acromicric dysplasia;C1858556:MASS syndrome;C1861456:Stiff skin syndrome;C1869115:Weill-Marchesani syndrome 2, dominant;C3280054:Geleophysic dysplasia 2;C3541518:Ectopia lentis 1, isolated, autosomal dominant;C4310796:Progeroid and marfanoid aspect-lipodystrophy syndrome (1)
1	-	-	Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Pathogenic	36
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.69	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
PhyloP100		7.9
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-4.6	D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.016	D
Vest4		0.85
MutPred		0.90		Loss of phosphorylation at T1237 (P = 0.1426)
MVP		0.98
MPC		1.4
ClinPred		1.0	D
GERP RS		5.9
Mutation Taster		=2/98	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
Splicevardb		1.0
SpliceAI score (max)		0.54		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.54		Position offset: -4

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

Other links and lift over

dbSNP: rs794728208; hg19: chr15-48777571;