chr20-58389494-C-T

Position:

• chr20-58389494-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_004738.5(VAPB):​c.35C>T​(p.Pro12Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P12S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: VAPB NM_004738.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.92

Genes affected

VAPB (HGNC:12649): (VAMP associated protein B and C) The protein encoded by this gene is a type IV membrane protein found in plasma and intracellular vesicle membranes. The encoded protein is found as a homodimer and as a heterodimer with VAPA. This protein also can interact with VAMP1 and VAMP2 and may be involved in vesicle trafficking. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a domain MSP (size 117) in uniprot entity VAPB_HUMAN there are 4 pathogenic changes around while only 1 benign (80%) in NM_004738.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.875

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
VAPB	NM_004738.5	c.35C>T	p.Pro12Leu	missense_variant	1/6	ENST00000475243.6
VAPB	NM_001195677.2	c.35C>T	p.Pro12Leu	missense_variant	1/3
VAPB	NR_036633.2	n.266C>T		non_coding_transcript_exon_variant	1/4
VAPB	XR_001754433.3	n.266C>T		non_coding_transcript_exon_variant	1/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
VAPB	ENST00000475243.6	c.35C>T	p.Pro12Leu	missense_variant	1/6	1	NM_004738.5	P1
VAPB	ENST00000395802.7	c.35C>T	p.Pro12Leu	missense_variant	1/3	1
VAPB	ENST00000265619.6	n.120C>T		non_coding_transcript_exon_variant	1/6	2
VAPB	ENST00000520497.1	c.35C>T	p.Pro12Leu	missense_variant, NMD_transcript_variant	1/4	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1442238 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 716014

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Jun 01, 2021

- -

Amyotrophic lateral sclerosis type 8;C1854058:Adult-onset proximal spinal muscular atrophy, autosomal dominant Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 18, 2020

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Not available"; PolyPhen-2: "Benign"; Align-GVGD: "Not available"). This variant has not been reported in the literature in individuals with VAPB-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces proline with leucine at codon 12 of the VAPB protein (p.Pro12Leu). The proline residue is moderately conserved and there is a moderate physicochemical difference between proline and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D;.
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Benign	0.57	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.87	D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Pathogenic	3.6	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-7.3	D;D
REVEL	Pathogenic	0.71
Sift	Benign	0.047	D;T
Sift4G	Uncertain	0.020	D;D
Polyphen		0.55	P;B
Vest4		0.65
MutPred		0.69		Loss of disorder (P = 0.0341);Loss of disorder (P = 0.0341);
MVP		0.78
MPC		0.59
ClinPred		1.0	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.73
gMVP		0.81

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

LitVar

Other links and lift over

dbSNP: rs1987730075; hg19: chr20-56964550;