Genetic Variant FBXL4:c.858+1G>A (chr6-98917373-C-T) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_001278716.2(FBXL4):c.858+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000698 in 1,433,284 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 7.0e-7 ( 0 hom. )

Consequence

FBXL4
NM_001278716.2 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.54

Publications

0 publications found

Variant links:

Genes affected

FBXL4 (HGNC:13601): (F-box and leucine rich repeat protein 4) This gene encodes a member of the F-box protein family, which are characterized by an approximately 40 amino acid motif, the F-box. F-box proteins constitute one subunit of modular E3 ubiquitin ligase complexes, called SCF complexes, which function in phosphorylation-dependent ubiquitination. The F-box domain mediates protein-protein interactions and binds directly to S-phase kinase-associated protein 1. In addition to an F-box domain, the encoded protein contains at least 9 tandem leucine-rich repeats. The ubiquitin ligase complex containing the encoded protein may function in cell-cycle control by regulating levels of lysine-specific demethylase 4A. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

FBXL4 Gene-Disease associations (from GenCC):

Leigh syndrome
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
mitochondrial DNA depletion syndrome 13
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet

FBXL4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.4, offset of -25, new splice context is: tggGTattt. 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;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBXL4	NM_001278716.2 link	c.858+1G>A		splice_donor_variant, intron_variant	Intron 5 of 9	ENST00000369244.7	NP_001265645.1	Q9UKA2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBXL4	ENST00000369244.7 link	c.858+1G>A		splice_donor_variant, intron_variant	Intron 5 of 9	1	NM_001278716.2	ENSP00000358247.1		Q9UKA2
FBXL4	ENST00000229971.2 link	c.858+1G>A		splice_donor_variant, intron_variant	Intron 4 of 8	1		ENSP00000229971.1		Q9UKA2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000432

AC:

AN:

231682

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000316

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.98e-7

AC:

AN:

1433284

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

710306

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:

32592

American (AMR)

AF:

0.0000242

AC:

AN:

41250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24152

East Asian (EAS)

AF:

0.00

AC:

AN:

39424

South Asian (SAS)

AF:

0.00

AC:

AN:

81244

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52344

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5558

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1097568

Other (OTH)

AF:

0.00

AC:

AN:

59152

⚠️ 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 v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Pathogenic

0.99

PhyloP100

7.5

GERP RS

4.6

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.92

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.92

Position offset: 1

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

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over