chr5-128272086-G-A

Variant names:

• chr5-128272086-G-A
• rs1554116411
• NM_001999.4:c.7873C>T

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_001999.4(FBN2):​c.7873C>T​(p.Gln2625*) variant causes a stop gained 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. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN2 NM_001999.4 stop_gained
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 10.0
• Publications: 0 publications found

Genes affected

FBN2 (HGNC:3604): (fibrillin 2) The protein encoded by this gene is a component of connective tissue microfibrils and may be involved in elastic fiber assembly. Mutations in this gene cause congenital contractural arachnodactyly. [provided by RefSeq, Jul 2008]

FBN2 Gene-Disease associations (from GenCC):

• congenital contractural arachnodactyly

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
• carpal tunnel syndrome

  Inheritance: AD Classification: LIMITED Submitted by: Franklin by Genoox
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• macular degeneration, early-onset

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 10 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN2	NM_001999.4	c.7873C>T	p.Gln2625*	stop_gained	Exon 62 of 65	ENST00000262464.9	NP_001990.2
FBN2	XM_017009228.3	c.7720C>T	p.Gln2574*	stop_gained	Exon 61 of 64		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN2	ENST00000262464.9	c.7873C>T	p.Gln2625*	stop_gained	Exon 62 of 65	1	NM_001999.4	ENSP00000262464.4
FBN2	ENST00000703783.1	n.4657C>T		non_coding_transcript_exon_variant	Exon 37 of 38
FBN2	ENST00000703784.1	n.40C>T		non_coding_transcript_exon_variant	Exon 2 of 2
FBN2	ENST00000703782.1	n.-13C>T		upstream_gene_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital contractural arachnodactyly Uncertain:1

Aug 09, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln2625*) in the FBN2 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in FBN2 cause disease. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. ClinVar contains an entry for this variant (Variation ID: 458781). This variant has not been reported in the literature in individuals affected with FBN2-related conditions. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	47
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.97	D
PhyloP100		10
Vest4		0.92
GERP RS		5.0
Mutation Taster		=4/196	disease causing (fs/PTC)

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

Other links and lift over

dbSNP: rs1554116411; hg19: chr5-127607778;