rs779844691

Positions:

• chr6-32850448-T-A
• chr6-32850448-T-C

Variant summary

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

The NM_000593.6(TAP1):​c.1120A>T​(p.Met374Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000958 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: TAP1 NM_000593.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.36

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]

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	Protein	UniProt
TAP1	NM_000593.6	c.1120A>T	p.Met374Leu	missense_variant	5/11	ENST00000354258.5	NP_000584.3
TAP1	NM_001292022.2	c.517A>T	p.Met173Leu	missense_variant	5/11		NP_001278951.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TAP1	ENST00000354258.5	c.1120A>T	p.Met374Leu	missense_variant	5/11	1	NM_000593.6	ENSP00000346206	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251472 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000958 AC: 14 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727242

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: 0.0000117

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

TwinsUK AF: 0.000270 AC: 1

ALSPAC AF: 0.00 AC: 0

ExAC AF: 0.00000824 AC: 1

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 01, 2018

This variant has not been reported in the literature in individuals with TAP1-related disease. 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 do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant is present in population databases (rs779844691, ExAC 0.001%). This sequence change replaces methionine with leucine at codon 434 of the TAP1 protein (p.Met434Leu). The methionine residue is moderately conserved and there is a small physicochemical difference between methionine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	24
DANN	Benign	0.97
DEOGEN2	Benign	0.22	T
Eigen	Pathogenic	0.70
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Uncertain	0.18	D
MetaRNN	Uncertain	0.72	D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Uncertain	2.2	M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-2.1	N
REVEL	Pathogenic	0.77
Sift	Benign	0.24	T
Sift4G	Benign	0.44	T
Polyphen		0.94	P
Vest4		0.49
MutPred		0.59		Gain of phosphorylation at T436 (P = 0.0767);
MVP		0.89
MPC		1.2
ClinPred		0.89	D
GERP RS		5.7
Varity_R		0.76
gMVP		0.80

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs779844691; hg19: chr6-32818225;