rs1555398836

Variant names:

• chr15-48490074-GA-G
• rs1555398836
• NM_000138.5:c.2858delT

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.2858delT​(p.Ile953ThrfsTer8) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 31)
• Consequence: FBN1 NM_000138.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.31

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 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 15-48490074-GA-G is Pathogenic according to our data. Variant chr15-48490074-GA-G is described in ClinVar as [Pathogenic]. Clinvar id is 439703.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.2858delT	p.Ile953ThrfsTer8	frameshift_variant	Exon 25 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.2858delT	p.Ile953ThrfsTer8	frameshift_variant	Exon 24 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.2858delT	p.Ile953ThrfsTer8	frameshift_variant	Exon 25 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Marfan syndrome Pathogenic:2

Mar 01, 2021

Centre of Medical Genetics, University of Antwerp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

PM2, PVS1, PP4 -

Nov 07, 2017

Center for Medical Genetics Ghent, University of Ghent

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not specified Pathogenic:1

Oct 19, 2016

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Mar 14, 2017

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The FBN1 c.2858delT (p.Ile953Thrfs) variant results in a premature termination codon, predicted to cause a truncated or absent FBN1 protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g., c.3973dupG [p.Glul1325fs). The variant lies within the TGFBP #3 functional domain (UMD) and one in silico tool predicts a damaging outcome for this variant. This variant is absent from the large control database ExAC (0/115756 control chromosomes). In addition, the variant has been cataloged in patient databases, such as UMD (UMD IDs 2349 and 2905), and was reported in the literature in a MFS patient fulfilling the revised Ghent criteria and classified as causative by the authors (Baetens_2011). Taken together, this variant is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

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: rs1555398836; hg19: chr15-48782271;