15-48495575-G-T

Position:

• chr15-48495575-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000138.5(FBN1):​c.2433C>A​(p.Cys811*) variant causes a stop gained change involving the alteration of a non-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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 0.374

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-48495575-G-T is Pathogenic according to our data. Variant chr15-48495575-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 36049.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5	c.2433C>A	p.Cys811*	stop_gained	21/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.2433C>A	p.Cys811*	stop_gained	20/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.2433C>A	p.Cys811*	stop_gained	21/66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics Laboratory, Skane University Hospital Lund	May 04, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	May 18, 2017	The C811X pathogenic variant in the FBN1 gene has been previously reported in association with Marfan syndrome (Hung et al., 2009; Wypasek et al., 2013). Hung et al. (2009) identified C811X in a Taiwanese patient or family fulfilling Ghent criteria for Marfan syndrome, although specific clinical information was not provided. Subsequently, Wypasek et al. (2013) reported C811X in a Polish female proband with Marfan syndrome. While the proband had several maternal relatives with clinical histories suspicious for Marfan syndrome, genetic testing of informative relatives was not performed at the time of publication (Wypasek et al., 2013). The C811X variant is classified in ClinVar as pathogenic or likely pathogenic by two other clinical laboratories (SCV000052362.1, SCV000319270.1; Landrum et al., 2016). C811X is predicted to cause loss of normal protein function either by protein truncation or nonsense-mediated mRNA decay. Multiple other nonsense variants in the FBN1 gene have been reported in Human Gene Mutation Database in association with FBN1-related disorders, including Marfan syndrome (Stenson et al., 2014). Furthermore, the C811X variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). -

Marfan syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Center for Medical Genetics Ghent, University of Ghent

Nov 07, 2017

- -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 07, 2020

The p.C811* pathogenic mutation (also known as c.2433C>A), located in coding exon 20 of the FBN1 gene, results from a C to A substitution at nucleotide position 2433. This changes the amino acid from a cysteine to a stop codon within coding exon 20. In a study of Taiwanese patients with Marfan syndrome, this mutation was detected in an individual fulfilling Ghent criteria with cardiovascular, ocular, and dural manifestations; this variant was also reported in one individual from a Polish Marfan syndrome cohort (Hung CC et al. Ann. Hum. Genet., 2009 Nov;73:559-67; Wypasek E et al. Pol. Arch. Med. Wewn., 2013;123:646-7). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Marfan Syndrome/Loeys-Dietz Syndrome/Familial Thoracic Aortic Aneurysms and Dissections Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Feb 10, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Uncertain	0.28
Eigen_PC	Benign	0.12
FATHMM_MKL	Uncertain	0.84	D
Vest4		0.92
GERP RS		0.99

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: rs193921256; hg19: chr15-48787772;