15-48494209-C-G

Position:

• chr15-48494209-C-G

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000138.5(FBN1):​c.2723G>C​(p.Cys908Ser) variant causes a missense 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C908R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.12

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 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-48494210-A-G is described in Lovd as [Likely_pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), FBN1. . Gene score misZ 5.0644 (greater than the threshold 3.09). Trascript score misZ 8.1787 (greater than threshold 3.09). GenCC has associacion of gene with MASS syndrome, Weill-Marchesani syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, Acromicric dysplasia, familial thoracic aortic aneurysm and aortic dissection, progeroid and marfanoid aspect-lipodystrophy syndrome, ectopia lentis 1, isolated, autosomal dominant, Marfan syndrome, Weill-Marchesani syndrome 2, dominant, isolated ectopia lentis, neonatal Marfan syndrome, stiff skin syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 15-48494209-C-G is Pathogenic according to our data. Variant chr15-48494209-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 389343.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-48494209-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5	c.2723G>C	p.Cys908Ser	missense_variant	23/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.2723G>C	p.Cys908Ser	missense_variant	22/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.2723G>C	p.Cys908Ser	missense_variant	23/66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Sep 21, 2016

A likely pathogenic variant has been identified in the FBN1 gene. The C908S variant has not been published as apathogenic variant, nor has it been reported as a benign variant to our knowledge. C908S was not observed inapproximately 6,500 individuals of European and African American ancestry in the NHLBI Exome SequencingProject, indicating it is not a common benign variant in these populations. The C908S variant is conserved acrossspecies, and is a non-conservative amino acid substitution, which is likely to impact secondary protein structure asthese residues differ in polarity, charge, size and/or other properties. Consequently, in silico analysis predicts thisvariant is probably damaging to the protein structure/function. Multiple other missense variants at the same residue(C908G, C908R, C908Y) have been reported in the Human Gene Mutation Database in association with Marfansyndrome (Stenson et al., 2014); however, the pathogenicity of these variants has not been definitely determined dueto lack of segregation and functional data. Moreover, while the C908S variant affects a Cysteine residue, it is notlocated within a calcium-binding EGF-like domain of the FBN1 gene. Cysteine substitutions in the calcium-bindingEGF-like domains represent the majority of pathogenic missense changes associated with Marfan syndrome (Collod-Beroud et al., 2003).In summary, C908S in the FBN1 gene is interpreted as a likely pathogenic variant. -

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 22, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	28
DANN	Uncertain	1.0
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.97	D
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-8.5	D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.025	D
Vest4		0.98
MutPred		0.92		Gain of disorder (P = 0.0088);
MVP		0.99
MPC		1.6
ClinPred		1.0	D
GERP RS		5.8

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: rs1057523406; hg19: chr15-48786406;