15-48411076-GGTTAA-G

Position:

• chr15-48411076-GGTTAA-G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000138.5(FBN1):​c.8525_8529del​(p.Leu2842ProfsTer7) 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 Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6 U:1
• Conservation: PhyloP100: 9.30

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 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 10 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-48411076-GGTTAA-G is Pathogenic according to our data. Variant chr15-48411076-GGTTAA-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 419823.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5	c.8525_8529del	p.Leu2842ProfsTer7	frameshift_variant	66/66	ENST00000316623.10
FBN1	NM_001406716.1	c.8525_8529del	p.Leu2842ProfsTer7	frameshift_variant	65/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10	c.8525_8529del	p.Leu2842ProfsTer7	frameshift_variant	66/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Marfan syndrome Pathogenic:2 Uncertain:1

Uncertain significance, no assertion criteria provided	clinical testing	Center for Medical Genetics Ghent, University of Ghent	Nov 07, 2017	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Apr 04, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 04, 2019

The c.8525_8529delTTAAC pathogenic mutation, located in coding exon 65 of the FBN1 gene, results from a deletion of 5 nucleotides at nucleotide positions 8525 to 8529, causing a translational frameshift with a predicted alternate stop codon (p.L2842Pfs*7). This mutation has been reported in multiple individuals with Marfan syndrome (Palz M et al. Am. J. Med. Genet., 2000 Mar;91:212-21; Rommel K et al. Hum. Mutat., 2005 Dec;26:529-39; Hung CC et al. Ann. Hum. Genet., 2009 Nov;73:559-67; Magyar I et al. Hum. Mutat., 2009 Sep;30:1355-64). 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

Oct 19, 2020

Variant summary: FBN1 c.8525_8529delTTAAC (p.Leu2842ProfsX7) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic in ClinVar database. The variant was absent in 251280 control chromosomes (gnomAD and publication data). c.8525_8529delTTAAC has been reported in the literature in individuals affected with Marfan Syndrome (Paiz_2000, Hung_2009, Magyar_2009, Aalberts_2014). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four ClinVar submitters (evaluation after 2014) cite the variant as pathogenic (3x) and uncertain significance (1x). Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 12, 2023

Not observed at significant frequency in large population cohorts (gnomAD); Frameshift variant predicted to result in protein truncation, as the last 30 amino acids are replaced with 6 different amino acids, and other loss-of-function variants have been reported downstream in HGMD; This variant is associated with the following publications: (PMID: 16220557, 19618372, 19839986, 10756346, 32679894, 33910934, 27611364, 24161884, 31098894, 12938084) -

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 02, 2023

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the FBN1 protein in which other variant(s) (p.Gln2867*) have been determined to be pathogenic (PMID: 19293843). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 419823). This premature translational stop signal has been observed in individual(s) with clinical features of FBN1-related conditions (PMID: 10756346, 19618372, 27611364). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Leu2842Profs*7) in the FBN1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 30 amino acid(s) of the FBN1 protein. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1064794130; hg19: chr15-48703273;