6-32845607-A-G

Position:

• chr6-32845607-A-G

Variant summary

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

The NM_000593.6(TAP1):​c.2219T>C​(p.Val740Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,770 control chromosomes in the GnomAD database, with no homozygous occurrence. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TAP1 NM_000593.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.14

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.2219T>C	p.Val740Ala	missense_variant	11/11	ENST00000354258.5
PSMB8-AS1	NR_037173.1	n.605A>G		non_coding_transcript_exon_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TAP1	ENST00000354258.5	c.2219T>C	p.Val740Ala	missense_variant	11/11	1	NM_000593.6	P1
PSMB8-AS1	ENST00000453426.2	n.379A>G		non_coding_transcript_exon_variant	2/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460770 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726700

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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:1

Revision: criteria provided, single submitter

Submissions by phenotype

MHC class I deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 29, 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). ClinVar contains an entry for this variant (Variation ID: 466387). This variant has not been reported in the literature in individuals affected with TAP1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 800 of the TAP1 protein (p.Val800Ala). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.018	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	22
DANN	Benign	0.91
DEOGEN2	Benign	0.31	T;.
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.13
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.68	.;T
M_CAP	Benign	0.022	T
MetaRNN	Uncertain	0.43	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.79	N;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-2.8	D;.
REVEL	Uncertain	0.32
Sift	Uncertain	0.026	D;.
Sift4G	Uncertain	0.025	D;.
Polyphen		0.63	P;.
Vest4		0.16
MutPred		0.73		Gain of disorder (P = 0.0266);.;
MVP		0.69
MPC		0.88
ClinPred		0.32	T
GERP RS		4.7
Varity_R		0.065
gMVP		0.35

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: rs1554242514; hg19: chr6-32813384;