15-48437354-C-T

Variant names:

• chr15-48437354-C-T
• rs1555395226
• NM_000138.5:c.6347G>A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_000138.5(FBN1):​c.6347G>A​(p.Gly2116Glu) 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.32

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 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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, 0.891

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.6347G>A	p.Gly2116Glu	missense_variant	Exon 52 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.6347G>A	p.Gly2116Glu	missense_variant	Exon 51 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.6347G>A	p.Gly2116Glu	missense_variant	Exon 52 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Oct 03, 2020

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G2116E variant (also known as c.6347G>A), located in coding exon 51 of the FBN1 gene, results from a G to A substitution at nucleotide position 6347, and is located in the TGFBP #06 domain. The glycine at codon 2116 is replaced by glutamic acid, an amino acid with similar properties. Based on internal structural analysis, this variant is anticipated to result in a significant decrease in structural stability (Downing AK et al. Cell, 1996 May 177;85(4):597-605; Ambry internal data). Another alteration impacting this amino acid (p.G2116A, c.6347G>C) has been reported in a patient with aortic root dilatation and pneumothorax but was also identified in an unaffected parent (Baudhuin LM et al. J. Hum. Genet., 2015 May;60:241-52). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	27
DANN	Uncertain	1.0
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.92	D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Uncertain	0.75	D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-4.6	D
REVEL	Pathogenic	0.83
Sift	Uncertain	0.016	D
Sift4G	Uncertain	0.021	D
Vest4		0.64
MutPred		0.78		Loss of glycosylation at S2115 (P = 0.0308);
MVP		0.98
MPC		0.90
ClinPred		0.99	D
GERP RS		5.5

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1555395226; hg19: chr15-48729551;