rs746473206

chr15-48448809-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PP2 PP3

The NM_000138.5(FBN1):c.5630A>G(p.His1877Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000411 in 1,460,848 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.15

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 Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000138.5
• PP2: Missense variant where missense usually causes diseases, FBN1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.747

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN1	NM_000138.5	c.5630A>G	p.His1877Arg	missense_variant	46/66	ENST00000316623.10
FBN1	NM_001406716.1	c.5630A>G	p.His1877Arg	missense_variant	45/65

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN1	ENST00000316623.10	c.5630A>G	p.His1877Arg	missense_variant	46/66	1	NM_000138.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000797 AC: 2 AN: 250958 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135616

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460848 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726762

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 16, 2018

This sequence change replaces histidine with arginine at codon 1877 of the FBN1 protein (p.His1877Arg). The histidine residue is highly conserved and there is a small physicochemical difference between histidine and arginine. This variant is present in population databases (rs746473206, ExAC 0.002%). This variant has not been reported in the literature in individuals with FBN1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.089	D
BayesDel_noAF	Benign	-0.090
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.43	T
M_CAP	Benign	0.049	D
MetaRNN	Pathogenic	0.75	D
MetaSVM	Uncertain	0.10	D
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-5.1	D
REVEL	Uncertain	0.49
Sift	Benign	0.13	T
Sift4G	Benign	0.20	T
Vest4		0.58
MutPred		0.64		Loss of ubiquitination at K1881 (P = 0.0715);
MVP		0.71
MPC		1.0
ClinPred		0.65	D
GERP RS		6.2

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: rs746473206; hg19: chr15-48741006;