rs886039066

Variant names:

• chr15-48520677-A-C
• NM_000138.5:c.1129T>G

Your query was ambiguous. Multiple possible variants found:

• chr15-48520677-A-C
• chr15-48520677-A-G

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000138.5(FBN1):​c.1129T>G​(p.Cys377Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C377R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.11

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]

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-48520677-A-G is described in Lovd as [Likely_pathogenic].
• 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 MASS syndrome, Weill-Marchesani syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, Acromicric dysplasia, familial thoracic aortic aneurysm and aortic dissection, progeroid and marfanoid aspect-lipodystrophy syndrome, ectopia lentis 1, isolated, autosomal dominant, Marfan syndrome, Weill-Marchesani syndrome 2, dominant, isolated ectopia lentis, neonatal Marfan syndrome, stiff skin syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 15-48520677-A-C is Pathogenic according to our data. Variant chr15-48520677-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2927220.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.1129T>G	p.Cys377Gly	missense_variant	Exon 10 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.1129T>G	p.Cys377Gly	missense_variant	Exon 9 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.1129T>G	p.Cys377Gly	missense_variant	Exon 10 of 66	1	NM_000138.5	ENSP00000325527.5
FBN1	ENST00000559133.6	n.1129T>G		non_coding_transcript_exon_variant	Exon 10 of 67	1		ENSP00000453958.2
FBN1	ENST00000674301.2	n.1129T>G		non_coding_transcript_exon_variant	Exon 10 of 68			ENSP00000501333.2
FBN1	ENST00000537463.6	n.636+17034T>G		intron_variant	Intron 7 of 30	5		ENSP00000440294.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

May 01, 2024

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.C377G variant (also known as c.1129T>G), located in coding exon 9 of the FBN1 gene, results from a T to G substitution at nucleotide position 1129. The cysteine at codon 377 is replaced by glycine, an amino acid with highly dissimilar properties. The majority of FBN1 mutations identified to date have involved the substitution or generation of cysteine residues within cbEGF domains (Vollbrandt T et al. J Biol Chem. 2004;279(31):32924-32931). Internal structural analysis indicates this alteration eliminates a disulfide bond critical for the structural integrity of the TB domain 1 (Ambry internal data). Another variant at the same codon, p.C377R (c.1129T>C), has been reported in an individual with a clinical diagnosis of Marfan syndrome (Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

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

Nov 27, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt FBN1 protein function. This missense change has been observed in individual(s) with Marfan syndrome (PMID: 29848614). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with glycine, which is neutral and non-polar, at codon 377 of the FBN1 protein (p.Cys377Gly). This variant disrupts the p.Cys377 amino acid residue in FBN1. Other variant(s) that disrupt this residue have been observed in individuals with FBN1-related conditions (PMID: 28855619, 33436942), which suggests that this may be a clinically significant amino acid residue. This variant affects a cysteine residue in the EGF-like, TGFBP or hybrid motif domains of FBN1. Cysteine residues are believed to be involved in intramolecular disulfide bridges and have been shown to be important for FBN1 protein structure (PMID: 16905551, 19349279). In addition, missense substitutions affecting cysteine residues within these domains are significantly overrepresented among patients with Marfan syndrome (PMID: 16571647, 17701892). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	28
DANN	Benign	0.94
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.94	D
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-9.2	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0070	D
Vest4		0.96
MutPred		0.99		Gain of disorder (P = 0.0773);
MVP		0.99
MPC		1.2
ClinPred		1.0	D
GERP RS		5.5

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr15-48812874;