15-48430769-C-T

Variant names:

• chr15-48430769-C-T
• rs886039047
• NM_000138.5:c.6773G>A

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000138.5(FBN1):​c.6773G>A​(p.Cys2258Tyr) variant causes a missense 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C2258R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.91

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 13 ACMG points.

• PM1: In a disulfide_bond (size 16) in uniprot entity FBN1_HUMAN there are 11 pathogenic changes around while only 0 benign (100%) in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-48430770-A-G is described in Lovd as [Likely_pathogenic].
• PP2: Missense variant in the FBN1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 1311 curated pathogenic missense variants (we use a threshold of 10). The gene has 112 curated benign missense variants. Gene score misZ: 5.0644 (above the threshold of 3.09). Trascript score misZ: 8.1787 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.995
• PP5: Variant 15-48430769-C-T is Pathogenic according to our data. Variant chr15-48430769-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 264106.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr15-48430769-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.6773G>A	p.Cys2258Tyr	missense_variant	Exon 56 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.6773G>A	p.Cys2258Tyr	missense_variant	Exon 55 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.6773G>A	p.Cys2258Tyr	missense_variant	Exon 56 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Jun 30, 2015

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.C2258Y variant (also known as c.6773G>A), located in coding exon 55 of the FBN1 gene, results from a G to A substitution at nucleotide position 6773. The cysteine at codon 2258 is replaced by tyrosine, an amino acid with highly dissimilar properties, and is located in the cb EGF-like domain #35. The majority of FBN1 mutations identified to date have involved the substitution or generation of cysteine residues within cbEGF domains (Vollbrandt T et al. J Biol Chem. 2004;279(31):32924-32931). This variant, which was described in a patient with classic Marfan syndrome (MFS), was studied using pulse-chase analysis that demonstrated a delay in secretion of profibrillin-1, which may disrupt the folding of the protein and its transport (Halliday D et al. Hum Genet, 1999 Dec;105:587-97). Based on internal structural assessment, this alteration eliminates a structurally critical disulfide bond in the structurally sensitive cb EGF-like domain #35. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

FBN1-related disorder Pathogenic:1

Jul 07, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The FBN1 c.6773G>A variant is predicted to result in the amino acid substitution p.Cys2258Tyr. This variant was reported in an individual with Marfan syndrome (Halliday et al. 1999. PubMed ID: 10647894). This variant has not been reported in a large population database, indicating this variant is rare. This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	29
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-8.8	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.024	D
Vest4		1.0
MutPred		0.91		Loss of methylation at K2261 (P = 0.053);
MVP		1.0
MPC		1.9
ClinPred		1.0	D
GERP RS		5.9

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: rs886039047; hg19: chr15-48722966; COSMIC: COSV57328175;