15-48463219-T-C

Position:

• chr15-48463219-T-C

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Very_Strong

The NM_000138.5(FBN1):​c.5087A>G​(p.Tyr1696Cys) 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 (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 4.90

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 15 ACMG points.

• PM1: In a domain TB 7 (size 55) in uniprot entity FBN1_HUMAN there are 23 pathogenic changes around while only 0 benign (100%) in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• 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, 0.92
• PP5: Variant 15-48463219-T-C is Pathogenic according to our data. Variant chr15-48463219-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 29699.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-48463219-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5	c.5087A>G	p.Tyr1696Cys	missense_variant	42/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.5087A>G	p.Tyr1696Cys	missense_variant	41/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.5087A>G	p.Tyr1696Cys	missense_variant	42/66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Geleophysic dysplasia 2 Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 04, 2018	- -
Likely pathogenic, criteria provided, single submitter	research	Human Genetics Section, Sidra Medicine	Feb 28, 2024	The missense variant is located in a mutational hot spot and missense variants are a common mechanism of disease. The variant is denovo. The same codon with a different amino acid change was found as a known pathogenic. ClinVar contains an entry for this variant (Variation ID: 29699). The variant is low in frequency in population databases (no frequency in GnomAD). We thus classify the variant as likely pathogenic -

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 03, 2023

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 1696 of the FBN1 protein (p.Tyr1696Cys). For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt FBN1 protein function. ClinVar contains an entry for this variant (Variation ID: 29699). This missense change has been observed in individual(s) with autosomal dominant geleophysic dysplasia (PMID: 21683322, 33082559). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	27
DANN	Uncertain	1.0
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.92	D
MetaSVM	Pathogenic	0.91	D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-7.0	D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0080	D
Vest4		0.98
MutPred		0.55		Gain of disorder (P = 0.1259);
MVP		0.99
MPC		1.5
ClinPred		0.99	D
GERP RS		6.0

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: rs387906625; hg19: chr15-48755416; COSMIC: COSV57311268;