rs1555398994

Positions:

• chr15-48492575-A-C
• chr15-48492575-A-G
• chr15-48492575-A-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Moderate

The NM_000138.5(FBN1):​c.2740T>G​(p.Cys914Gly) 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. 11/18 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.32

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 11 ACMG points.

• PM1: In a domain EGF-like 14; calcium-binding (size 41) in uniprot entity FBN1_HUMAN there are 5 pathogenic changes around while only 1 benign (83%) in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), FBN1. . Gene score misZ: 5.0644 (greater than the threshold 3.09). Trascript score misZ: 8.1787 (greater than threshold 3.09). The gene has 1311 curated pathogenic missense variants (we use a threshold of 10). The gene has 112 curated benign missense variants. GenCC has associacion of the gene with 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, 0.996
• PP5: Variant 15-48492575-A-C is Pathogenic according to our data. Variant chr15-48492575-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 520236.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5	c.2740T>G	p.Cys914Gly	missense_variant	24/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.2740T>G	p.Cys914Gly	missense_variant	23/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.2740T>G	p.Cys914Gly	missense_variant	24/66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 23, 2015

The p.C914G variant (also known as c.2740T>G), located in coding exon 23 of the FBN1 gene, results from a T to G substitution at nucleotide position 2740. The cysteine at codon 914 is replaced by glycine, an amino acid with highly dissimilar properties. An alteration at the same amino acid position, p.C914S, was reported in an individual with Marfan<span style="line-height:13.8667px">syndrom (Stheneur<span style="line-height:13.8667px">C et al<span style="line-height:13.8667px">,<em style="line-height:13.8667px">Eur. J. Hum. Genet<span style="line-height:13.8667px">. 2009 Sep; 17(9):1121-8) and also in multple related affected individuals from a family (Cabrera-Bueno F et al, J. Cardiol. Cases 2014; 10:235-357).This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6494 samples (12988 alleles) with coverage at this position. 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 variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	29
DANN	Uncertain	0.98
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	0.90	D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-10	D
REVEL	Pathogenic	0.99
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.010	D
Vest4		0.99
MutPred		0.98		Loss of stability (P = 0.0116);
MVP		0.99
MPC		1.6
ClinPred		1.0	D
GERP RS		6.0

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: rs1555398994; hg19: chr15-48784772;