chr5-128349445-C-T

Position:

• chr5-128349445-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_001999.4(FBN2):​c.2891G>A​(p.Gly964Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. G964C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: FBN2 NM_001999.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.84

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 Uncertain_significance. Variant got 3 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN2	NM_001999.4	c.2891G>A	p.Gly964Asp	missense_variant	23/65	ENST00000262464.9
FBN2	XM_017009228.3	c.2738G>A	p.Gly913Asp	missense_variant	22/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN2	ENST00000262464.9	c.2891G>A	p.Gly964Asp	missense_variant	23/65	1	NM_001999.4	P1
FBN2	ENST00000508989.5	c.2792G>A	p.Gly931Asp	missense_variant	22/33	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital contractural arachnodactyly Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 24, 2017

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with FBN2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with aspartic acid at codon 964 of the FBN2 protein (p.Gly964Asp). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and aspartic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D;.;D;D
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.98	D;.;.;D
M_CAP	Uncertain	0.17	D
MetaRNN	Uncertain	0.74	D;D;D;D
MetaSVM	Uncertain	0.60	D
MutationAssessor	Benign	0.81	L;.;L;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.1	D;.;D;D
REVEL	Pathogenic	0.76
Sift	Benign	0.078	T;.;T;T
Sift4G	Benign	0.17	.;.;.;T
Polyphen		1.0	D;.;D;D
Vest4		0.86
MutPred		0.55		Loss of catalytic residue at C966 (P = 0.0901);.;Loss of catalytic residue at C966 (P = 0.0901);.;
MVP		0.77
MPC		0.84
ClinPred		0.99	D
GERP RS		4.2
Varity_R		0.60
gMVP		0.69

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: rs1554124089; hg19: chr5-127685137;