Genetic Variant FBN2:c.1466-5C>A (chr5-128392160-G-T) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_001999.4(FBN2):c.1466-5C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,254 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

FBN2
NM_001999.4 splice_region, intron

Scores

Splicing: ADA: 0.9970

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.102

Publications

0 publications found

Variant links:

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)

FBN2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001999.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FBN2	NM_001999.4	MANE Select	c.1466-5C>A		splice_region intron	N/A	NP_001990.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein
FBN2	ENST00000262464.9	TSL:1 MANE Select	c.1466-5C>A	splice_region intron	N/A	ENSP00000262464.4
FBN2	ENST00000508989.5	TSL:2	c.1367-5C>A	splice_region intron	N/A	ENSP00000425596.1
FBN2	ENST00000703787.1		n.1173-5C>A	splice_region intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460254

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726508

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33442

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26114

East Asian (EAS)

AF:

0.00

AC:

AN:

39612

South Asian (SAS)

AF:

0.00

AC:

AN:

86216

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53242

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110816

Other (OTH)

AF:

0.00

AC:

AN:

60336

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.84

CADD

Benign

(source)

DANN

Benign

0.53

PhyloP100

-0.10

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Benign

0.69

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.99

Position offset: -2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over