rs370973542

chr5-128350963-C-Achr5-128350963-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_001999.4(FBN2):c.2717G>T(p.Arg906Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,614,022 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. R906H) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FBN2 NM_001999.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.17

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 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, FBN2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.911

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN2	NM_001999.4	c.2717G>T	p.Arg906Leu	missense_variant	21/65	ENST00000262464.9
FBN2	XM_017009228.3	c.2564G>T	p.Arg855Leu	missense_variant	20/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN2	ENST00000262464.9	c.2717G>T	p.Arg906Leu	missense_variant	21/65	1	NM_001999.4	P1
FBN2	ENST00000508989.5	c.2618G>T	p.Arg873Leu	missense_variant	20/33	2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152140 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251404 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135882

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461882 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727246

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152140 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74306

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 12, 2018

A variant of uncertain significance has been identified in the FBN2 gene. The R906L variant has not been published as pathogenic or been reported as benign to our knowledge. This variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016). The R906L variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Although this substitution occurs at a position where amino acids with similar properties to arginine (R) are tolerated across species, in silico analysis predicts this variant is probably damaging to the protein structure/function. Nevertheless, the R906L variant 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 CCA (Collod-Beroud et al., 2003; Frédéric et al., 2009). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.49
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.71	D;.;D;T
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.47
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.93	D;.;.;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.91	D;D;D;D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Pathogenic	3.2	M;.;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.57	T
PROVEAN	Pathogenic	-6.1	D;.;D;D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0030	D;.;D;D
Polyphen		0.080	B;.;B;D
Vest4		0.77
MutPred		0.75		Loss of catalytic residue at N901 (P = 0.2324);.;Loss of catalytic residue at N901 (P = 0.2324);.;
MVP		0.76
MPC		0.73
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.56
gMVP		0.77

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: rs370973542; hg19: chr5-127686655;