22-28795632-T-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001079539.2(XBP1):c.674A>C(p.Tyr225Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,612,898 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: XBP1 NM_001079539.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.553

Genes affected

XBP1 (HGNC:12801): (X-box binding protein 1) This gene encodes a transcription factor that regulates MHC class II genes by binding to a promoter element referred to as an X box. This gene product is a bZIP protein, which was also identified as a cellular transcription factor that binds to an enhancer in the promoter of the T cell leukemia virus type 1 promoter. It may increase expression of viral proteins by acting as the DNA binding partner of a viral transactivator. It has been found that upon accumulation of unfolded proteins in the endoplasmic reticulum (ER), the mRNA of this gene is processed to an active form by an unconventional splicing mechanism that is mediated by the endonuclease inositol-requiring enzyme 1 (IRE1). The resulting loss of 26 nt from the spliced mRNA causes a frame-shift and an isoform XBP1(S), which is the functionally active transcription factor. The isoform encoded by the unspliced mRNA, XBP1(U), is constitutively expressed, and thought to function as a negative feedback regulator of XBP1(S), which shuts off transcription of target genes during the recovery phase of ER stress. A pseudogene of XBP1 has been identified and localized to chromosome 5. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.059242368).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
XBP1	NM_001079539.2	c.674A>C	p.Tyr225Ser	missense_variant	6/6	ENST00000344347.6
XBP1	NM_001393999.1	c.524A>C	p.Tyr175Ser	missense_variant	6/6
XBP1	NM_005080.4	c.700A>C	p.Thr234Pro	missense_variant	5/5
XBP1	NM_001394000.1	c.550A>C	p.Thr184Pro	missense_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
XBP1	ENST00000344347.6	c.674A>C	p.Tyr225Ser	missense_variant	6/6	5	NM_001079539.2	P4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152108 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000800 AC: 2 AN: 250108 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135178

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000582

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460790 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726670

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000449

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: 0.00000270

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152108 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74302

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 29, 2022

The c.700A>C (p.T234P) alteration is located in exon 5 (coding exon 5) of the XBP1 gene. This alteration results from a A to C substitution at nucleotide position 700, causing the threonine (T) at amino acid position 234 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.064
BayesDel_addAF	Benign	-0.34	T
BayesDel_noAF	Benign	-0.65
Cadd	Benign	14
Dann	Benign	0.94
DEOGEN2	Benign	0.097	T;T;T
Eigen	Benign	-0.55
Eigen_PC	Benign	-0.47
FATHMM_MKL	Benign	0.30	N
LIST_S2	Benign	0.39	T;T;T
M_CAP	Benign	0.0036	T
MetaRNN	Benign	0.059	T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-0.37	N;N;N
REVEL	Benign	0.055
Sift	Benign	0.12	T;T;T
Sift4G	Benign	0.30	T;T;T
Polyphen		0.0010	.;.;B
Vest4		0.095
MutPred		0.17		.;.;Loss of phosphorylation at T184 (P = 0.0103);
MVP		0.34
MPC		0.66
ClinPred		0.070	T
GERP RS		2.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.10
gMVP		0.12

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: rs763098411; hg19: chr22-29191620;