5-128312775-A-G

Position:

• chr5-128312775-A-G

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2 BS2

The NM_001999.4(FBN2):​c.4738T>C​(p.Tyr1580His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000616 in 1,461,610 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: FBN2 NM_001999.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.30

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 -3 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.
• BS2: High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN2	NM_001999.4	c.4738T>C	p.Tyr1580His	missense_variant	37/65	ENST00000262464.9	NP_001990.2
FBN2	XM_017009228.3	c.4585T>C	p.Tyr1529His	missense_variant	36/64		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN2	ENST00000262464.9	c.4738T>C	p.Tyr1580His	missense_variant	37/65	1	NM_001999.4	ENSP00000262464	P1
FBN2	ENST00000703783.1	n.1522T>C		non_coding_transcript_exon_variant	12/38
FBN2	ENST00000703785.1	n.1583-822T>C		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461610 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 727120

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: 0.00000719

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

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

Dec 13, 2016

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a FBN2-related disease. This sequence change replaces tyrosine with histidine at codon 1580 of the FBN2 protein (p.Tyr1580His). The tyrosine residue is highly conserved and there is a moderate physicochemical difference between tyrosine and histidine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.75
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D;.;D
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;.;.
M_CAP	Pathogenic	0.29	D
MetaRNN	Uncertain	0.59	D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	3.2	M;.;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.80	D
PROVEAN	Uncertain	-3.9	D;.;D
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D;.;D
Polyphen		0.99	D;.;D
Vest4		0.49
MutPred		0.51		Gain of disorder (P = 0.0271);.;Gain of disorder (P = 0.0271);
MVP		0.82
MPC		0.95
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.72
gMVP		0.84

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1060503508; hg19: chr5-127648467;