rs794728287

chr15-48411126-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_000138.5(FBN1):c.8480A>C(p.Tyr2827Ser) 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 Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:6
• Conservation: PhyloP100: 7.99

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 Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, FBN1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5	c.8480A>C	p.Tyr2827Ser	missense_variant	66/66	ENST00000316623.10
FBN1	NM_001406716.1	c.8480A>C	p.Tyr2827Ser	missense_variant	65/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10	c.8480A>C	p.Tyr2827Ser	missense_variant	66/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 29, 2021	Variant summary: FBN1 c.8480A>C (p.Tyr2827Ser) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251398 control chromosomes, however the available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.8480A>C in individuals affected with Marfan Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Three ClinVar submitters provided clinical-significance assessments for this variant after 2014, all classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Feb 28, 2019	The FBN1 c.8480A>C; p.Tyr2827Ser variant (rs794728287), to our knowledge, is not reported in the medical literature but is reported as uncertain significance in ClinVar (Variation ID: 200135). This variant is absent from general population databases (Exome Variant Server, Genome Aggregation Database), indicating it is not a common polymorphism. The tyrosine at codon 2827 is moderately conserved, and computational analyses (SIFT, PolyPhen-2) predict that this variant may be deleterious. However, given the lack of clinical and functional data, the significance of this variant is uncertain at this time. -

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Jan 06, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Apr 27, 2018	p.Tyr2827Ser (TAT>TCT): c.8480 A>C in exon 66 of the FBN1 gene (NM_000138.4)The Tyr2827Ser variant in the FBN1 gene has not been reported as a disease-causing mutation or as a benign polymorphism to our knowledge. Tyr2827Ser results in a semi-conservative amino acid substitution of a larger polar Tyrosine with a polar Serine at a position that is conserved across species. In silico analysis predicts Tyr2827Ser is possibly damaging to the protein structure/function. A mutation in a nearby codon (Ser2832Gly) has been reported in association with Marfan syndrome, supporting the functional importance of this region of the protein. Also, the Tyr2827Ser variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations.With the clinical and molecular information available at this time, we cannot definitively determine if Tyr2827Ser is a disease-causing mutation or a rare benign variant. The variant is found in TAAD panel(s). -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 16, 2023

The p.Y2827S variant (also known as c.8480A>C), located in coding exon 65 of the FBN1 gene, results from an A to C substitution at nucleotide position 8480. The tyrosine at codon 2827 is replaced by serine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 03, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with FBN1-related disease. ClinVar contains an entry for this variant (Variation ID: 200135). This variant is not present in population databases (ExAC no frequency). This sequence change replaces tyrosine with serine at codon 2827 of the FBN1 protein (p.Tyr2827Ser). The tyrosine residue is highly conserved and there is a large physicochemical difference between tyrosine and serine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.60
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
Cadd	Pathogenic	26
Dann	Uncertain	0.99
Eigen	Uncertain	0.68
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Uncertain	0.37	D
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0070	D
Sift4G	Uncertain	0.0070	D
Vest4		0.78
MVP		0.95
MPC		1.1
ClinPred		0.99	D
GERP RS		5.0

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

Publications

LitVar

Other links and lift over

dbSNP: rs794728287; hg19: chr15-48703323;