chr7-128849329-A-T

Position:

• chr7-128849329-A-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 18P and 4B. PVS1 PM2 PP5_Very_Strong BS2

The NM_001458.5(FLNC):​c.4952-2A>T variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000342 in 1,461,776 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: FLNC NM_001458.5 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.11

Genes affected

FLNC (HGNC:3756): (filamin C) This gene encodes one of three related filamin genes, specifically gamma filamin. These filamin proteins crosslink actin filaments into orthogonal networks in cortical cytoplasm and participate in the anchoring of membrane proteins for the actin cytoskeleton. Three functional domains exist in filamin: an N-terminal filamentous actin-binding domain, a C-terminal self-association domain, and a membrane glycoprotein-binding domain. Mutations in this gene are a cause of cardiopathy. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3, offset of -17, new splice context is: cccaccagctccctgagcAGgat. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-128849329-A-T is Pathogenic according to our data. Variant chr7-128849329-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 570065.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FLNC	NM_001458.5	c.4952-2A>T		splice_acceptor_variant, intron_variant		ENST00000325888.13	NP_001449.3
FLNC	NM_001127487.2	c.4952-2A>T		splice_acceptor_variant, intron_variant			NP_001120959.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FLNC	ENST00000325888.13	c.4952-2A>T		splice_acceptor_variant, intron_variant		1	NM_001458.5	ENSP00000327145.8
FLNC	ENST00000346177.6	c.4952-2A>T		splice_acceptor_variant, intron_variant		1		ENSP00000344002.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249264 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135294

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: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461776 Hom.: 0 Cov.: 36 AF XY: 0.00000413 AC XY: 3 AN XY: 727174

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: 0.00000360

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000827 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 15, 2023

Canonical splice site variant predicted to result in a null allele in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign in association with an FLNC-related disorder to our knowledge; This variant is associated with the following publications: (PMID: 35699965) -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 10, 2022

The c.4952-2A>T intronic variant results from an A to T substitution two nucleotides upstream from coding exon 30 in the FLNC gene. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site and will result in the creation or strengthening of a novel splice acceptor site. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -

Myofibrillar myopathy 5;C3279722:Distal myopathy with posterior leg and anterior hand involvement;C4310749:Hypertrophic cardiomyopathy 26;CN239310:Dilated Cardiomyopathy, Dominant Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 24, 2023

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 570065). This variant has not been reported in the literature in individuals affected with FLNC-related conditions. This variant is present in population databases (rs774945928, gnomAD 0.0009%). This sequence change affects an acceptor splice site in intron 29 of the FLNC gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in FLNC are known to be pathogenic (PMID: 27908349). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.8
RBP_binding_hub_radar		0.77
RBP_regulation_power_radar		2.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.78		Position offset: 28
DS_AL_spliceai		0.99		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs774945928; hg19: chr7-128489383;