rs375487064

Variant names:

• chr5-128304952-C-T
• rs375487064
• NM_001999.4:c.5800+5G>A

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 3P and 4B. PP3_Moderate PP5 BS2

The NM_001999.4(FBN2):​c.5800+5G>A variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00012 in 1,613,866 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00013 (0 hom.)
• Consequence: FBN2 NM_001999.4 splice_region, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:5
• Conservation: PhyloP100: 7.35
• Publications: 0 publications found

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]

FBN2 Gene-Disease associations (from GenCC):

• congenital contractural arachnodactyly

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
• carpal tunnel syndrome

  Inheritance: AD Classification: LIMITED Submitted by: Franklin by Genoox
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• macular degeneration, early-onset

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 5-128304952-C-T is Pathogenic according to our data. Variant chr5-128304952-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 213404.
• BS2: High AC in GnomAd4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN2	NM_001999.4	c.5800+5G>A		splice_region_variant, intron_variant	Intron 45 of 64	ENST00000262464.9	NP_001990.2
FBN2	XM_017009228.3	c.5647+5G>A		splice_region_variant, intron_variant	Intron 44 of 63		XP_016864717.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN2	ENST00000262464.9	c.5800+5G>A		splice_region_variant, intron_variant	Intron 45 of 64	1	NM_001999.4	ENSP00000262464.4
FBN2	ENST00000703783.1	n.2584+5G>A		splice_region_variant, intron_variant	Intron 20 of 37
FBN2	ENST00000703785.1	n.2503+5G>A		splice_region_variant, intron_variant	Intron 19 of 26

Frequencies

GnomAD3 genomes AF: 0.0000526 AC: 8 AN: 152130 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: 0.000103

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000677 AC: 17 AN: 251146 AF XY: 0.0000958

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000869

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.000106

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000127 AC: 186 AN: 1461736 Hom.: 0 Cov.: 31 AF XY: 0.000128 AC XY: 93 AN XY: 727170

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.0000671 AC: 3 AN: 44684

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.0000187 AC: 1 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.000160 AC: 178 AN: 1111924

Other (OTH) AF: 0.0000662 AC: 4 AN: 60392

GnomAD4 genome AF: 0.0000526 AC: 8 AN: 152130 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74306

African (AFR) AF: 0.0000241 AC: 1 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15264

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000103 AC: 7 AN: 68026

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000989 Hom.: 0

Bravo AF: 0.0000416

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:5

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Congenital contractural arachnodactyly Pathogenic:1 Uncertain:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 45 of the FBN2 gene. It does not directly change the encoded amino acid sequence of the FBN2 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs375487064, gnomAD 0.01%). This variant has been observed in individuals with clinical features of congenital contractural arachnodactyly and/or thoracic aortic aneurysm and dissection (internal data). ClinVar contains an entry for this variant (Variation ID: 213404). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Nonsyndromic Heritable Thoracic Aortic Aneurysms And Dissections Pathogenic:1

Feb 21, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: FBN2 c.5800+5G>A alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: One predicts the variant abolishes a canonical 5' splicing donor site. Three predict the variant weakens the canonical 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 6.8e-05 in 251146 control chromosomes. While at a frequency exceeding that of Congenital Contractural Arachnodactyly (CCA), this frequency is not significantly higher than estimated for a pathogenic variant in FBN2 causing Nonsyndromic Heritable Thoracic Aortic Aneurysms And Dissections, allowing no conclusion about variant significance. c.5800+5G>A has been observed in individuals with clinical features of Congenital Contractural Arachnodactyly and/or Thoracic Aortic Aneurysm and Dissection (internal data). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. ClinVar contains an entry for this variant (Variation ID: 213404). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

not specified Uncertain:1

Aug 25, 2016

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Jun 07, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.5800+5G>A intronic variant results from a G to A substitution 5 nucleotides after coding exon 45 in the FBN2 gene. This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. Based on the available evidence, the clinical significance of this variant remains unclear. -

not provided Uncertain:1

May 22, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Has not been previously published as pathogenic or benign to our knowledge; In silico analysis indicates that this variant does not alter splicing -

Congenital contractural arachnodactyly;C4015286:Macular degeneration, early-onset Uncertain:1

Mar 07, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.15
CADD	Benign	22
DANN	Uncertain	0.97
PhyloP100		7.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs375487064; hg19: chr5-127640644;