chr6-33304214-A-T

Position:

• chr6-33304214-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The ENST00000434618.7(TAPBP):​c.1214T>A​(p.Leu405His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: TAPBP ENST00000434618.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.38

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.23190236).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TAPBP	NM_003190.5	c.1214T>A	p.Leu405His	missense_variant	6/8	ENST00000434618.7	NP_003181.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TAPBP	ENST00000434618.7	c.1214T>A	p.Leu405His	missense_variant	6/8	1	NM_003190.5	ENSP00000395701	P2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000756

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

Dec 13, 2019

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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with TAPBP-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with histidine at codon 405 of the TAPBP protein (p.Leu405His). The leucine residue is weakly conserved and there is a moderate physicochemical difference between leucine and histidine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	18
DANN	Benign	0.95
DEOGEN2	Benign	0.024	.;T;.;T
Eigen	Benign	0.018
Eigen_PC	Benign	-0.11
FATHMM_MKL	Benign	0.16	N
LIST_S2	Benign	0.79	T;T;T;T
M_CAP	Benign	0.029	D
MetaRNN	Benign	0.23	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N;N;N;N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-1.6	N;N;N;N
REVEL	Benign	0.086
Sift	Uncertain	0.0090	D;D;T;D
Sift4G	Uncertain	0.0040	D;D;D;D
Polyphen		0.98	.;D;.;.
Vest4		0.35
MVP		0.37
MPC		1.2
ClinPred		0.41	T
GERP RS		4.2
gMVP		0.36

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: rs1768785371; hg19: chr6-33271991;