15-48474263-G-T

Variant names:

• chr15-48474263-G-T
• rs1555397648
• NM_000138.5:c.4202C>A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP2

The NM_000138.5(FBN1):​c.4202C>A​(p.Thr1401Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 13/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1401A) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.56

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a domain EGF-like 23; calcium-binding (size 40) in uniprot entity FBN1_HUMAN there are 18 pathogenic changes around while only 1 benign (95%) 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 chrnull-null-null-null is described in UniProt as null.
• 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.4202C>A	p.Thr1401Asn	missense_variant	Exon 34 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.4202C>A	p.Thr1401Asn	missense_variant	Exon 33 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.4202C>A	p.Thr1401Asn	missense_variant	Exon 34 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jul 13, 2016

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Thr1401Asn variant in FBN1 has not been previously reported in individuals with pulmonary disease or in large population studies. Computational prediction tools and conservation analysis do not provide strong support for or against an impact to the protein. In summary, the clinical significance of the p.Thr1401As n variant is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.085
BayesDel_addAF	Benign	-0.034	T
BayesDel_noAF	Benign	-0.29
CADD	Uncertain	25
DANN	Benign	0.95
Eigen	Benign	-0.15
Eigen_PC	Benign	0.050
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.054	D
MetaRNN	Uncertain	0.66	D
MetaSVM	Benign	-0.40	T
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-2.2	N
REVEL	Benign	0.25
Sift	Benign	0.084	T
Sift4G	Benign	0.22	T
Vest4		0.62
MutPred		0.46		Loss of phosphorylation at T1401 (P = 0.1145);
MVP		0.62
MPC		0.69
ClinPred		0.50	T
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1555397648; hg19: chr15-48766460;