rs886038943

Positions:

• chr15-48437027-T-G

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000138.5(FBN1):​c.6430A>C​(p.Asn2144His) 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. N2144S) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 8.02

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 19 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain 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 chr15-48437026-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 16431.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, FBN1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 15-48437027-T-G is Pathogenic according to our data. Variant chr15-48437027-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 263837.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-48437027-T-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5	c.6430A>C	p.Asn2144His	missense_variant	53/66	ENST00000316623.10
FBN1	NM_001406716.1	c.6430A>C	p.Asn2144His	missense_variant	52/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10	c.6430A>C	p.Asn2144His	missense_variant	53/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 07, 2014

The p.N2144H variant (also known as c.6430A>C), located in coding exon 52 of the FBN1 gene, results from an A to C substitution at nucleotide position 6430. The asparagine at codon 2144 is replaced by histidine, an amino acid with some similar properties.Two other alterations at the same codon in the cbEGF-like #32 domain, p.N2144D (c.6430A>G) and p.N2144S (c.6431A>G), have been reported previously in patients with Marfan syndrome; p.N2144S (also known as p.N1246S) affects calcium binding (Comgelio P et al. Hum Mutat. 2007;28(9):928; Hewett DR et al. Hum Mol Genet. 1993;2(4):475-477).This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project.In the ESP, this variant was not observed in 6494 samples (12,988 alleles) with coverage at this position.This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive.Based on the majority of available evidence to date, the p.N2144H variant is likely to be pathogenic. -

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Oct 03, 2021

ClinVar contains an entry for this variant (Variation ID: 263837). This missense change has been observed in individual(s) with Marfan syndrome (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces asparagine with histidine at codon 2144 of the FBN1 protein (p.Asn2144His). The asparagine residue is highly conserved and there is a small physicochemical difference between asparagine and histidine. 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. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Asn2144 amino acid residue in FBN1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 7896820, 8504310, 11829507, 12938084, 16220557, 17657824). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	27
DANN	Uncertain	1.0
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Vest4		0.90
MutPred		0.95		Gain of catalytic residue at N2144 (P = 0.0751);
MVP		0.98
MPC		1.4
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: rs886038943; hg19: chr15-48729224;