rs34383505

Positions:

• chr5-128259461-G-C

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BA1

The NM_001999.4(FBN2):​c.8733C>G​(p.Leu2911=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0043 in 1,613,046 control chromosomes in the GnomAD database, including 238 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.023 (129 hom., cov: 32)
  • Exomes 𝑓: 0.0023 (109 hom.)
• Consequence: FBN2 NM_001999.4 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:9
• Conservation: PhyloP100: 0.279

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 Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.5).
• BP6: Variant 5-128259461-G-C is Benign according to our data. Variant chr5-128259461-G-C is described in ClinVar as [Benign]. Clinvar id is 137357.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr5-128259461-G-C is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=0.279 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0769 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FBN2	NM_001999.4	c.8733C>G	p.Leu2911=	synonymous_variant	65/65	ENST00000262464.9	NP_001990.2
FBN2	XM_017009228.3	c.8580C>G	p.Leu2860=	synonymous_variant	64/64		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FBN2	ENST00000262464.9	c.8733C>G	p.Leu2911=	synonymous_variant	65/65	1	NM_001999.4	ENSP00000262464	P1

Frequencies

GnomAD3 genomes AF: 0.0230 AC: 3501 AN: 152110 Hom.: 128 Cov.: 32

Gnomad AFR AF: 0.0792

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0102

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000621

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00949

Gnomad NFE AF: 0.000265

Gnomad OTH AF: 0.0196

GnomAD3 exomes AF: 0.00629 AC: 1579 AN: 251150 Hom.: 43 AF XY: 0.00457 AC XY: 620 AN XY: 135724

Gnomad AFR exome AF: 0.0763

Gnomad AMR exome AF: 0.00847

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000196

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000106

Gnomad OTH exome AF: 0.00457

GnomAD4 exome AF: 0.00234 AC: 3422 AN: 1460818 Hom.: 109 Cov.: 31 AF XY: 0.00196 AC XY: 1424 AN XY: 726722

Gnomad4 AFR exome AF: 0.0779

Gnomad4 AMR exome AF: 0.00843

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.000139

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000104

Gnomad4 OTH exome AF: 0.00484

GnomAD4 genome AF: 0.0231 AC: 3510 AN: 152228 Hom.: 129 Cov.: 32 AF XY: 0.0226 AC XY: 1681 AN XY: 74432

Gnomad4 AFR AF: 0.0792

Gnomad4 AMR AF: 0.0102

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000829

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000265

Gnomad4 OTH AF: 0.0194

Alfa AF: 0.00643 Hom.: 8

Bravo AF: 0.0260

Asia WGS AF: 0.00260 AC: 9 AN: 3478

EpiCase AF: 0.000164

EpiControl AF: 0.000178

ClinVar

Significance: Benign

Submissions summary: Benign:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:2

Benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 12, 2013	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -

not provided Benign:2

Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 29, 2017	Variant summary: The FBN2 c.8733C>G (p.Leu2911Leu) variant involves the alteration of a non-conserved nucleotide, resulting in a synonymous change. The variant does not lie within a known functional domain and one in silico tool predicts a damaging outcome for this variant. 5/5 splice prediction tools predict no significant impact on normal splicing and ESE finder predicts that this variant may create an SF2/ASF ESE site at the locus. However, these predictions have yet to be confirmed by functional studies. This variant was found in the large control database ExAC at a frequency of 0.0077117 (936/121374 control chromosomes [26 homozygotes]), which is approximately 6169 times the estimated maximal expected allele frequency of a pathogenic FBN2 variant (0.0000013), suggesting this variant is likely a benign polymorphism. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as benign. To our knowledge, the variant of interest has not been reported in affected individuals via publications, nor has it been evaluated for functional impact by in vivo/vitro studies. Taken together, this variant is classified as benign. -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Oct 14, 2023	- -

Congenital contractural arachnodactyly Benign:2

Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 29, 2024	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Familial thoracic aortic aneurysm and aortic dissection Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 06, 2015

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Ehlers-Danlos syndrome Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

Jun 14, 2022

- -

Connective tissue disorder Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

Nov 24, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.50
CADD	Benign	0.90
DANN	Benign	0.68

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: rs34383505; hg19: chr5-127595153;