Genetic Variant TAPBP:p.Ala155Val (chr6-33313222-G-A) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003190.5(TAPBP):c.464C>T(p.Ala155Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,452,962 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A155G) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

TAPBP
NM_003190.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 2.87

Publications

0 publications found

Variant links:

Genes affected

TAPBP (HGNC:11566): (TAP binding protein) This gene encodes a transmembrane glycoprotein which mediates interaction between newly assembled major histocompatibility complex (MHC) class I molecules and the transporter associated with antigen processing (TAP), which is required for the transport of antigenic peptides across the endoplasmic reticulum membrane. This interaction is essential for optimal peptide loading on the MHC class I molecule. Up to four complexes of MHC class I and this protein may be bound to a single TAP molecule. This protein contains a C-terminal double-lysine motif (KKKAE) known to maintain membrane proteins in the endoplasmic reticulum. This gene lies within the major histocompatibility complex on chromosome 6. Alternative splicing results in three transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

TAPBP Gene-Disease associations (from GenCC):

MHC class I deficiency
Inheritance: AR Classification: MODERATE, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen

TAPBP links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TAPBP	NM_003190.5 link	c.464C>T	p.Ala155Val	missense_variant	Exon 3 of 8	ENST00000434618.7	NP_003181.3	O15533-1A0A024RCT1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TAPBP	ENST00000434618.7 link	c.464C>T	p.Ala155Val	missense_variant	Exon 3 of 8	1	NM_003190.5	ENSP00000395701.2		O15533-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.88e-7

AC:

AN:

1452962

Hom.:

Cov.:

AF XY:

0.00000139

AC XY:

AN XY:

720952

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:

33288

American (AMR)

AF:

0.00

AC:

AN:

44360

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25980

East Asian (EAS)

AF:

0.00

AC:

AN:

39450

South Asian (SAS)

AF:

0.0000116

AC:

AN:

85980

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53300

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5748

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1104996

Other (OTH)

AF:

0.00

AC:

AN:

59860

⚠️ 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: 0.325

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

AlphaMissense

Benign

0.23

BayesDel_addAF

Benign

-0.069

BayesDel_noAF

Benign

-0.34

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.026

.;T;T;.

Eigen

Uncertain

0.33

Eigen_PC

Uncertain

0.28

FATHMM_MKL

Benign

0.53

LIST_S2

Benign

0.75

T;T;T;T

M_CAP

Benign

0.011

MetaRNN

Benign

0.25

T;T;T;T

MetaSVM

Benign

-0.96

PhyloP100

2.9

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-1.3

N;N;N;N

REVEL

Benign

0.086

Sift

Benign

0.20

T;D;T;T

Sift4G

Pathogenic

0.0

D;D;D;.

Polyphen

1.0

.;D;.;.

Vest4

0.35

MutPred

0.45

Loss of helix (P = 3e-04);Loss of helix (P = 3e-04);Loss of helix (P = 3e-04);.;

MVP

0.63

MPC

0.41

ClinPred

0.90

GERP RS

3.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

gMVP

0.40

Mutation Taster

=75/25

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.23

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.23

Position offset: 2

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