4-152323085-GC-G

Variant names:

• chr4-152323085-GC-G
• NM_001349798.2:c.1919delG

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_001349798.2(FBXW7):​c.1919delG​(p.Ser640ThrfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBXW7 NM_001349798.2 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.88

Genes affected

FBXW7 (HGNC:16712): (F-box and WD repeat domain containing 7) This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene was previously referred to as FBX30, and belongs to the Fbws class; in addition to an F-box, this protein contains 7 tandem WD40 repeats. This protein binds directly to cyclin E and probably targets cyclin E for ubiquitin-mediated degradation. Mutations in this gene are detected in ovarian and breast cancer cell lines, implicating the gene's potential role in the pathogenesis of human cancers. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 6 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-152323085-GC-G is Pathogenic according to our data. Variant chr4-152323085-GC-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3255132.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBXW7	NM_001349798.2	c.1919delG	p.Ser640ThrfsTer7	frameshift_variant	Exon 14 of 14	ENST00000281708.10	NP_001336727.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBXW7	ENST00000281708.10	c.1919delG	p.Ser640ThrfsTer7	frameshift_variant	Exon 14 of 14	1	NM_001349798.2	ENSP00000281708.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental delay, hypotonia, and impaired language Pathogenic:1

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with developmental delay, hypotonia, and impaired language (MIM#620012). However, additional mechanisms for missense variants have not been excluded (PMID: 35395208). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0115 - Variants in this gene are known to have variable expressivity. Variants that segregated within families displayed intrafamilial variability (PMID: 35395208). (I) 0205 - Variant is predicted to result in a truncated protein (premature termination codon is NOT located at least 54 nucleotides upstream of the final exon-exon junction) with less than 1/3 of the protein sequence affected. (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0601 - Variant results in the partial loss of the WD40 domain (DECIPHER). Additionally, functional studies have proven that missense variation in the truncated C-terminal region can impact protein function (PMID: 35395208). (SP) 0704 - Another protein truncating variant comparable to the one identified in this case has limited previous evidence for pathogenicity. A truncating variant (p.(Lys647*)) has been reported as likely pathogenic, and observed as de novo in an individual with a milder neurodevelopmental syndrome (ClinVar, PMID: 35395208). Another truncating variant (p.(Ser641*)), has been reported as a VUS in an individual with unknown inheritance and features including hypotonia with motor delay (DECIPHER). (SP) 0807 - This variant has no previous evidence of pathogenicity. (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1207 - Parental origin of the variant is unresolved (by duo analysis). This variant is not maternally inherited. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Computational scores

Source: dbNSFP v4.3

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr4-153244237;