15-48610775-C-A

Variant names:

• chr15-48610775-C-A
• rs397515782
• NM_000138.5:c.299G>T

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000138.5(FBN1):​c.299G>T​(p.Cys100Phe) 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. C100Y) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.48

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 13 ACMG points.

• PM1: In a disulfide_bond (size 11) in uniprot entity FBN1_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) 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 chr15-48610775-C-T is described in Lovd as [Likely_pathogenic].
• 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, 0.946
• PP5: Variant 15-48610775-C-A is Pathogenic according to our data. Variant chr15-48610775-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 42322.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr15-48610775-C-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.299G>T	p.Cys100Phe	missense_variant	Exon 4 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.299G>T	p.Cys100Phe	missense_variant	Exon 3 of 65		NP_001393645.1
FBN1	NM_001406717.1	c.299G>T	p.Cys100Phe	missense_variant	Exon 4 of 9		NP_001393646.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.299G>T	p.Cys100Phe	missense_variant	Exon 4 of 66	1	NM_000138.5	ENSP00000325527.5
FBN1	ENST00000559133.6	n.299G>T		non_coding_transcript_exon_variant	Exon 4 of 67	1		ENSP00000453958.2
FBN1	ENST00000537463.6	n.299G>T		non_coding_transcript_exon_variant	Exon 4 of 31	5		ENSP00000440294.2
FBN1	ENST00000674301.2	n.299G>T		non_coding_transcript_exon_variant	Exon 4 of 68			ENSP00000501333.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Marfan syndrome Pathogenic:1

Apr 19, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Cys100Phe variant (FBN1) has not been reported in the literature nor previou sly identified by our laboratory. A different change at the same amino acid (Cys 100Tyr) has been reported in one individual with Marfan syndrome and was absent in 100 control chromosomes (Chung 2009), suggesting that changes to this positio n may not be tolerated. In addition, computational analyses (biochemical amino a cid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) suggest that the C ys100Phe variant may impact the protein. Furthermore, this variant affects a cys teine residue; cysteine substitutions are a common finding in individuals with M arfan syndrome (Schrijver 1999). In summary, this variant is likely to be pathog enic, though segregation studies and functional analyses are required to fully e stablish the pathogenicity of this variant. The clinical significance of this s equence variant should be interpreted in the context of this individual's clinic al manifestation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-6.2	D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Vest4		0.93
MutPred		0.74		Loss of glycosylation at S104 (P = 0.1051);
MVP		0.98
MPC		1.8
ClinPred		1.0	D
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs397515782; hg19: chr15-48902972;