rs775707895

Positions:

• chr15-48485476-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 5P and 3B. PM1 PM2 PP2 BP4_Moderate BP6

The NM_000138.5(FBN1):​c.3610A>G​(p.Met1204Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,866 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 1.53

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 2 ACMG points.

• PM1: In a domain EGF-like 19; calcium-binding (size 40) in uniprot entity FBN1_HUMAN there are 13 pathogenic changes around while only 0 benign (100%) in NM_000138.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), FBN1. . Gene score misZ 5.0644 (greater than the threshold 3.09). Trascript score misZ 8.1787 (greater than threshold 3.09). GenCC has associacion of gene with 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.23213655).
• BP6: Variant 15-48485476-T-C is Benign according to our data. Variant chr15-48485476-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 527204.We mark this variant Likely_benign, oryginal submissions are: {Benign=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN1	NM_000138.5	c.3610A>G	p.Met1204Val	missense_variant	30/66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.3610A>G	p.Met1204Val	missense_variant	29/65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.3610A>G	p.Met1204Val	missense_variant	30/66	1	NM_000138.5	ENSP00000325527	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461866 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727238

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 31, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

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

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 07, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Uncertain	0.024	T
BayesDel_noAF	Benign	-0.20
CADD	Benign	20
DANN	Benign	0.93
Eigen	Benign	-0.43
Eigen_PC	Benign	-0.18
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.79	T
M_CAP	Benign	0.035	D
MetaRNN	Benign	0.23	T
MetaSVM	Benign	-0.73	T
MutationTaster	Benign	0.86	D
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-2.0	N
REVEL	Benign	0.29
Sift	Benign	0.28	T
Sift4G	Benign	0.29	T
Vest4		0.44
MutPred		0.44		Gain of catalytic residue at M1204 (P = 0.02);
MVP		0.68
MPC		0.53
ClinPred		0.22	T
GERP RS		4.9

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: rs775707895; hg19: chr15-48777673;