5-128311329-T-G

Position:

• chr5-128311329-T-G

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2 BP4 BS2

The NM_001999.4(FBN2):​c.5045A>C​(p.Tyr1682Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,814 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y1682C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: FBN2 NM_001999.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 2.25

Genes affected

FBN2 (HGNC:3604): (fibrillin 2) The protein encoded by this gene is a component of connective tissue microfibrils and may be involved in elastic fiber assembly. Mutations in this gene cause congenital contractural arachnodactyly. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), FBN2. . Gene score misZ 1.5491 (greater than the threshold 3.09). Trascript score misZ 3.2752 (greater than threshold 3.09). GenCC has associacion of gene with familial thoracic aortic aneurysm and aortic dissection, carpal tunnel syndrome, macular degeneration, early-onset, congenital contractural arachnodactyly.
• BP4: Computational evidence support a benign effect (MetaRNN=0.3549022).
• BS2: High AC in GnomAdExome4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN2	NM_001999.4	c.5045A>C	p.Tyr1682Ser	missense_variant	39/65	ENST00000262464.9
FBN2	XM_017009228.3	c.4892A>C	p.Tyr1631Ser	missense_variant	38/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN2	ENST00000262464.9	c.5045A>C	p.Tyr1682Ser	missense_variant	39/65	1	NM_001999.4	P1
FBN2	ENST00000703783.1	n.1829A>C		non_coding_transcript_exon_variant	14/38
FBN2	ENST00000703785.1	n.1748A>C		non_coding_transcript_exon_variant	13/27

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251224 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135776

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: 0.0000327

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461814 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 727196

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: 0.0000232

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 15, 2023

The p.Y1682S variant (also known as c.5045A>C), located in coding exon 39 of the FBN2 gene, results from an A to C substitution at nucleotide position 5045. The tyrosine at codon 1682 is replaced by serine, an amino acid with dissimilar properties. This amino acid position is well 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 02, 2022

Has not been previously published as pathogenic or benign to our knowledge; Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Does not affect a cysteine residue within a calcium-binding EGF-like domain of the FBN2 gene; cysteine substitutions in the calcium-binding EGF-like domains represent the majority of pathogenic missense changes associated with FBN2-related disorders (Frederic et al., 2009); This variant is associated with the following publications: (PMID: 18767143) -

Congenital contractural arachnodactyly Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 03, 2023

This sequence change replaces tyrosine, which is neutral and polar, with serine, which is neutral and polar, at codon 1682 of the FBN2 protein (p.Tyr1682Ser). This variant is present in population databases (rs769474473, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with FBN2-related conditions. ClinVar contains an entry for this variant (Variation ID: 547360). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on FBN2 protein function. 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. -

Connective tissue disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Nov 01, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	27
DANN	Benign	0.97
DEOGEN2	Uncertain	0.64	D;.;D
Eigen	Benign	-0.30
Eigen_PC	Benign	-0.033
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.86	D;.;.
M_CAP	Benign	0.037	D
MetaRNN	Benign	0.35	T;T;T
MetaSVM	Benign	-0.37	T
MutationAssessor	Benign	-0.22	N;.;N
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-3.8	D;.;D
REVEL	Uncertain	0.57
Sift	Benign	0.17	T;.;T
Polyphen		0.073	B;.;B
Vest4		0.49
MutPred		0.56		Gain of disorder (P = 0.0095);.;Gain of disorder (P = 0.0095);
MVP		0.96
MPC		0.46
ClinPred		0.23	T
GERP RS		5.5
Varity_R		0.50
gMVP		0.87

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: rs769474473; hg19: chr5-127647021;