rs397515753

Positions:

• chr15-48520755-G-A

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.1051C>T​(p.Gln351Ter) variant causes a stop gained change. 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: 32)
• Consequence: FBN1 NM_000138.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.19

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 15-48520755-G-A is Pathogenic according to our data. Variant chr15-48520755-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 42280.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.1051C>T	p.Gln351Ter	stop_gained	10/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.1051C>T	p.Gln351Ter	stop_gained	9/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.1051C>T	p.Gln351Ter	stop_gained	10/66	1	NM_000138.5	ENSP00000325527	P1
FBN1	ENST00000559133.6	c.1051C>T	p.Gln351Ter	stop_gained, NMD_transcript_variant	10/67	1		ENSP00000453958
FBN1	ENST00000674301.2	c.1051C>T	p.Gln351Ter	stop_gained, NMD_transcript_variant	10/68			ENSP00000501333
FBN1	ENST00000537463.6	c.636+16956C>T		intron_variant, NMD_transcript_variant		5		ENSP00000440294

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Marfan syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Sep 13, 2012

The Gln351X variant in FBN1 has been reported in one individual with clinical fe atures of Marfan syndrome (Comeglio 2007). This nonsense variant leads to a prem ature termination codon at position 351, which is predicted to lead to a truncat ed or absent protein. Heterozygous loss of function of the FBN1 gene is an estab lished disease mechanism in Marfan syndrome. In summary, this variant meets our criteria to be classified as pathogenic (http://pcpgm.partners.org/LMM). -

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 06, 2023

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 42280). This premature translational stop signal has been observed in individuals with Marfan syndrome (PMID: 17657824, 24199744). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln351*) in the FBN1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in FBN1 are known to be pathogenic (PMID: 17657824, 19293843). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	41
DANN	Uncertain	1.0
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	A
Vest4		0.95
GERP RS		5.7

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: rs397515753; hg19: chr15-48812952;