6-32845731-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000593.6(TAP1):c.2095A>G(p.Ile699Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TAP1 NM_000593.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.50

Genes affected

TAP1 (HGNC:43): (transporter 1, ATP binding cassette subfamily B member) The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance. The protein encoded by this gene is involved in the pumping of degraded cytosolic peptides across the endoplasmic reticulum into the membrane-bound compartment where class I molecules assemble. Mutations in this gene may be associated with ankylosing spondylitis, insulin-dependent diabetes mellitus, and celiac disease. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2014]

PSMB8-AS1 (HGNC:39758): (PSMB8 antisense RNA 1 (head to head))

PSMB9 (HGNC:9546): (proteasome 20S subunit beta 9) The proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. The core structure is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. This gene encodes a member of the proteasome B-type family, also known as the T1B family, that is a 20S core beta subunit. This gene is located in the class II region of the MHC (major histocompatibility complex). Expression of this gene is induced by gamma interferon and this gene product replaces catalytic subunit 1 (proteasome beta 6 subunit) in the immunoproteasome. Proteolytic processing is required to generate a mature subunit. [provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TAP1	NM_000593.6	c.2095A>G	p.Ile699Val	missense_variant	11/11	ENST00000354258.5
PSMB8-AS1	NR_037173.1	n.729T>C		non_coding_transcript_exon_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TAP1	ENST00000354258.5	c.2095A>G	p.Ile699Val	missense_variant	11/11	1	NM_000593.6	P1
PSMB8-AS1	ENST00000453426.2	n.503T>C		non_coding_transcript_exon_variant	2/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000406 AC: 1 AN: 246178 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 134252

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000906

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

MHC class I deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 07, 2022

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with TAP1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 759 of the TAP1 protein (p.Ile759Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Benign	0.011	T
BayesDel_noAF	Benign	-0.22
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.10	T;.
Eigen	Benign	0.12
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.80	D
M_CAP	Benign	0.053	D
MetaRNN	Uncertain	0.53	D;D
MetaSVM	Benign	-0.73	T
MutationAssessor	Benign	-0.12	N;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-0.65	N;.
REVEL	Uncertain	0.32
Sift	Benign	0.050	D;.
Sift4G	Benign	0.13	T;.
Polyphen		0.67	P;.
Vest4		0.41
MutPred		0.83		Gain of disorder (P = 0.1523);.;
MVP		0.69
MPC		0.73
ClinPred		0.46	T
GERP RS		5.8
Varity_R		0.066
gMVP		0.29

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: rs1414081966; hg19: chr6-32813508;