6-32841558-C-T

Position:

• chr6-32841558-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_148919.4(PSMB8):​c.715G>A​(p.Asp239Asn) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,460,516 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: PSMB8 NM_148919.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.10

Genes affected

PSMB8 (HGNC:9545): (proteasome 20S subunit beta 8) 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 3 (proteasome beta 5 subunit) in the immunoproteasome. Proteolytic processing is required to generate a mature subunit. Two alternative transcripts encoding two isoforms have been identified; both isoforms are processed to yield the same mature subunit. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PSMB8	NM_148919.4	c.715G>A	p.Asp239Asn	missense_variant	5/6	ENST00000374882.8	NP_683720.2
PSMB8	NM_004159.5	c.703G>A	p.Asp235Asn	missense_variant	5/6		NP_004150.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PSMB8	ENST00000374882.8	c.715G>A	p.Asp239Asn	missense_variant	5/6	1	NM_148919.4	ENSP00000364016	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460516 Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3 AN XY: 726580

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Proteosome-associated autoinflammatory syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 07, 2018

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: "Probably Damaging"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals with PSMB8-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces aspartic acid with asparagine at codon 239 of the PSMB8 protein (p.Asp239Asn). The aspartic acid residue is highly conserved and there is a small physicochemical difference between aspartic acid and asparagine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.79
BayesDel_addAF	Benign	-0.013	T
BayesDel_noAF	Benign	-0.26
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.16	T;T;.
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Uncertain	0.21	D
MutationAssessor	Pathogenic	3.6	.;H;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.72	T
PROVEAN	Pathogenic	-4.4	D;D;D
REVEL	Uncertain	0.57
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	.;D;D
Vest4		0.96
MutPred		0.90		.;Gain of MoRF binding (P = 0.0312);.;
MVP		0.86
MPC		1.5
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.94
gMVP		0.96

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: rs1554238810; hg19: chr6-32809335;