chr15-48427755-C-T

Variant names:

• chr15-48427755-C-T
• rs1555394580
• NM_000138.5:c.7016G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PP2 PP3 PS4_Supporting PM2_Supporting PM1 PM5

This summary comes from the ClinGen Evidence Repository: NM_00138 c. 7016G>A is a missense variant in FBN1 predicted to cause a substitution of cysteine by tyrosine at amino acid 2339 (p.Cys2339Tyr). This variant has been identified in one individual with clinical features of Marfan syndrome (PS4_Sup). This variant has been reported 1 time in ClinVar as Likely pathogenic and 1 time as uncertain significance (VariationID:495644).This variant is not present in gnomAD (PM2_Sup; https://gnomad.broadinstitute.org/ v4.0.0). This variant affects a cysteine residue in a TB domain. Cysteine residues are believed to be involved in the formation of disulfide bridges which are essential for the protein structure (PM1). The constraint z-score for missense variants affecting FBN1 is 8.18 (PP2; https://gnomad.broadinstitute.org/ v4.0.0). Computational prediction tools and conservation analysis suggest that this variant may impact the protein (REVEL: 0.992, PP3). In summary, this variant meets criteria to be classified as likely pathogenic for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: PM1, PM5, PS4_Sup, PM2_Sup, PP2, PP3. LINK:https://erepo.genome.network/evrepo/ui/classification/CA392330332/MONDO:0007947/022

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:2 U:1
• Conservation: PhyloP100: 7.91
• Publications: 1 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):

• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Marfan syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P, PanelApp Australia, Orphanet, Ambry Genetics
• 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: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• 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: AD, Unknown Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 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.
• PP2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.7016G>A	p.Cys2339Tyr	missense_variant	Exon 58 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.7016G>A	p.Cys2339Tyr	missense_variant	Exon 57 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.7016G>A	p.Cys2339Tyr	missense_variant	Exon 58 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

Marfan syndrome Pathogenic:2

Feb 08, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Cys2339Tyr variant in FBN1 has been reported in 1 individual with clinical features of Marfan syndrome (Katzke 2002) and was absent from large population studies. Computational prediction tools and conservation analysis suggest that t he p.Cys2339Tyr variant may impact the protein. Two other variants at this amino acid position (p.Cys2239Gly, p.Cys2239arg) have also been reported in individua ls with Marfan syndrome (Rybczynski 2008, Ogawa 2011), suggesting that changes a t this position may not be tolerated. In addition, the p.Cys2339Tyr variant affe cts a cysteine residue; cysteine substitutions are a common finding in individua ls with Marfan syndrome (Schrijver 1999). In summary, although additional studie s are required to fully establish its clinical significance, the p.Cys2339Tyr va riant is likely pathogenic. ACMG/AMP Criteria applied (Richards 2015): PM1; PM2; PP3; PS4_supporting. -

Aug 22, 2024

ClinGen FBN1 Variant Curation Expert Panel, ClinGen

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

NM_00138 c. 7016G>A is a missense variant in FBN1 predicted to cause a substitution of cysteine by tyrosine at amino acid 2339 (p.Cys2339Tyr). This variant has been identified in one individual with clinical features of Marfan syndrome (PS4_Sup). This variant has been reported 1 time in ClinVar as Likely pathogenic and 1 time as uncertain significance (VariationID:495644).This variant is not present in gnomAD (PM2_Sup; https://gnomad.broadinstitute.org/ v4.0.0). This variant affects a cysteine residue in a TB domain. Cysteine residues are believed to be involved in the formation of disulfide bridges which are essential for the protein structure (PM1). The constraint z-score for missense variants affecting FBN1 is 8.18 (PP2; https://gnomad.broadinstitute.org/ v4.0.0). Computational prediction tools and conservation analysis suggest that this variant may impact the protein (REVEL: 0.992, PP3). In summary, this variant meets criteria to be classified as likely pathogenic for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: PM1, PM5, PS4_Sup, PM2_Sup, PP2, PP3. -

not provided Uncertain:1

Feb 17, 2017

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The FBN1 c.7016G>A (p.Cys2339Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. 4/4 in silico tools predict a damaging outcome for this variant (SNPs&GO not captured due to low reliability index) although these predictions have yet to be functionally assessed. This variant is absent in 119,502 control chromosomes. The variant of interest lies in a conserved region within a TGF-beta binding (TB) domain. Many manifestations of Marfan syndrome relate to excess activation and signaling by the growth factor TGF-beta (Dietz_2005)." This variant determines the substitution of cysteine with tyrosine. The sulfhydryl group of cysteine is unique in its ability to participate in disulfide covalent cross-linkage. In fact, two thirds of fibrillin cysteine residues exist in the half-cystinyl form, suggesting their participation in intramolecular disulfide linkage. Therefore, alteration of cysteine in this domain could disrupt disulfide binding, effecting secondary or tertiary structure or possibly impairing fibrillin interactions. Additionally, this variant was reported in a patient with Marfan syndrome. No clinical laboratories cite the variant of interest. Therefore, taking all available lines of evidence, the variant of interest is classified as VUS-possibly pathogenic until additional information becomes available. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	29
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
PhyloP100		7.9
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-9.6	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0060	D
Vest4		1.0
MutPred		0.86		Loss of disorder (P = 0.0603);
MVP		1.0
MPC		1.9
ClinPred		1.0	D
GERP RS		5.4
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs1555394580; hg19: chr15-48719952;