chr8-99819403-A-G

Variant names:

• chr8-99819403-A-G
• rs386834116
• NM_017890.5:c.8697-9A>G

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The NM_017890.5(VPS13B):​c.8697-9A>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,226 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: VPS13B NM_017890.5 intron
• Scores: Splicing: ADA: 0.9865
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 0.240
• Publications: 1 publications found

Genes affected

VPS13B (HGNC:2183): (vacuolar protein sorting 13 homolog B) This gene encodes a potential transmembrane protein that may function in vesicle-mediated transport and sorting of proteins within the cell. This protein may play a role in the development and the function of the eye, hematological system, and central nervous system. Mutations in this gene have been associated with Cohen syndrome. Multiple splice variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

VPS13B Gene-Disease associations (from GenCC):

• Cohen syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Laboratory for Molecular Medicine, ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 8-99819403-A-G is Pathogenic according to our data. Variant chr8-99819403-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 56697.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
VPS13B	NM_017890.5	c.8697-9A>G		intron_variant	Intron 47 of 61	ENST00000358544.7	NP_060360.3
VPS13B	NM_152564.5	c.8622-9A>G		intron_variant	Intron 47 of 61	ENST00000357162.7	NP_689777.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
VPS13B	ENST00000358544.7	c.8697-9A>G		intron_variant	Intron 47 of 61	1	NM_017890.5	ENSP00000351346.2
VPS13B	ENST00000357162.7	c.8622-9A>G		intron_variant	Intron 47 of 61	1	NM_152564.5	ENSP00000349685.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250926 AF XY: 0.00000737

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461226 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726914

African (AFR) AF: 0.00 AC: 0 AN: 33452

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39644

South Asian (SAS) AF: 0.0000232 AC: 2 AN: 86216

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111582

Other (OTH) AF: 0.00 AC: 0 AN: 60366

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cohen syndrome Pathogenic:4

Feb 03, 2023

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: VPS13B c.8697-9A>G alters a non-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: Four predict the variant creates a cryptic 3' acceptor site eight nucleotides upstream into intron 47. Two predict the variant abolishes the canonical 3' acceptor site and one predicts the variant weakens the canonical 3' acceptor site. This impact on splicing was confirmed via cDNA sequencing by Athanasakis_2012. The variant allele was found at a frequency of 4e-06 in 250926 control chromosomes (gnomAD). c.8697-9A>G has been reported in the literature in at least one compound heterozygous individuals affected with Cohen Syndrome (Athanasakis_2012). These data do not allow any conclusion about variant significance. Two ClinVar submitters have assessed the variant since 2014: one classified the variant as likely pathogenic, and one as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

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Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Feb 06, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 47 of the VPS13B gene. It does not directly change the encoded amino acid sequence of the VPS13B protein. This variant is present in population databases (rs386834116, gnomAD 0.003%). This variant has been observed in individual(s) with Cohen syndrome (PMID: 22855652). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 56697). 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. -

May 08, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Jul 29, 2024

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; This variant is associated with the following publications: (PMID: 22855652) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	15
DANN	Benign	0.43
PhyloP100		0.24
Mutation Taster		=29/71	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.97
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		1.0		Position offset: 1
DS_AL_spliceai		0.99		Position offset: 9

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

Other links and lift over

dbSNP: rs386834116; hg19: chr8-100831631;