15-48445469-A-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PS1 PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000138.5(FBN1):c.5824T>A(p.Cys1942Ser) variant causes a missense change. 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 nucleotide change resulting in same amino acid change has been previously reported as Pathogenicin ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1942R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.12

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.

• PS1: Transcript NM_000138.5 (FBN1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 263804
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-48445469-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 811411.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, FBN1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986
• PP5: Variant 15-48445469-A-T is Pathogenic according to our data. Variant chr15-48445469-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1067779.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5	c.5824T>A	p.Cys1942Ser	missense_variant	48/66	ENST00000316623.10
FBN1	NM_001406716.1	c.5824T>A	p.Cys1942Ser	missense_variant	47/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10	c.5824T>A	p.Cys1942Ser	missense_variant	48/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Mar 31, 2020

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. This variant disrupts the p.Cys1942 amino acid residue in FBN1. Other variant(s) that disrupt this residue have been observed in individuals with FBN1-related conditions (Invitae), which suggests that this may be a clinically significant amino acid residue. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has been observed in individual(s) with clinical features of Marfan syndrome (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces cysteine with serine at codon 1942 of the FBN1 protein (p.Cys1942Ser). The cysteine residue is highly conserved and there is a moderate physicochemical difference between cysteine and serine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
Cadd	Pathogenic	27
Dann	Uncertain	0.99
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-9.0	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.051	T
Vest4		0.83
MutPred		0.89		Gain of disorder (P = 0.0101);
MVP		0.99
MPC		0.71
ClinPred		0.99	D
GERP RS		5.8

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: chr15-48737666;