20-1181323-C-T

Variant summary

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

The NM_001304748.2(TMEM74B):c.296G>A(p.Arg99Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000381 in 1,601,526 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000038 (1 hom.)
• Consequence: TMEM74B NM_001304748.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.672

Genes affected

TMEM74B (HGNC:15893): (transmembrane protein 74B) Predicted to be integral component of membrane. [provided by Alliance of Genome Resources, Apr 2022]

PSMF1 (HGNC:9571): (proteasome inhibitor subunit 1) The 26S proteasome is a multicatalytic proteinase complex with a highly ordered structure composed of 2 complexes, a 20S core and a 19S regulator. The 20S core 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. The 19S regulator is composed of a base, which contains 6 ATPase subunits and 2 non-ATPase subunits, and a lid, which contains up to 10 non-ATPase 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 protein that inhibits the activation of the proteasome by the 11S and 19S regulators. Alternative transcript variants have been identified for this gene. [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=0.030439138).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM74B	NM_001304748.2	c.296G>A	p.Arg99Gln	missense_variant	3/3	ENST00000429036.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM74B	ENST00000429036.2	c.296G>A	p.Arg99Gln	missense_variant	3/3	3	NM_001304748.2	P1

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152190 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000622

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000583 AC: 14 AN: 240022 Hom.: 1 AF XY: 0.0000697 AC XY: 9 AN XY: 129058

Gnomad AFR exome AF: 0.0000621

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.000226

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000217

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000369

Gnomad OTH exome AF: 0.000171

GnomAD4 exome AF: 0.0000380 AC: 55 AN: 1449218 Hom.: 1 Cov.: 31 AF XY: 0.0000473 AC XY: 34 AN XY: 719360

Gnomad4 AFR exome AF: 0.0000900

Gnomad4 AMR exome AF: 0.0000227

Gnomad4 ASJ exome AF: 0.000119

Gnomad4 EAS exome AF: 0.0000253

Gnomad4 SAS exome AF: 0.000286

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000154

Gnomad4 OTH exome AF: 0.0000669

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152308 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74464

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000622

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000693 Hom.: 0

Bravo AF: 0.0000340

ExAC AF: 0.0000330 AC: 4

Asia WGS AF: 0.000577 AC: 2 AN: 3478

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

Jan 08, 2024

The c.296G>A (p.R99Q) alteration is located in exon 2 (coding exon 2) of the TMEM74B gene. This alteration results from a G to A substitution at nucleotide position 296, causing the arginine (R) at amino acid position 99 to be replaced by a glutamine (Q). 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	0.073
BayesDel_addAF	Benign	-0.44	T
BayesDel_noAF	Benign	-0.58
Cadd	Benign	18
Dann	Uncertain	1.0
DEOGEN2	Benign	0.020	T;T
Eigen	Benign	-0.42
Eigen_PC	Benign	-0.36
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Benign	0.79	T;T
M_CAP	Benign	0.0063	T
MetaRNN	Benign	0.030	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.5	L;.
MutationTaster	Benign	0.67	D
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-0.84	N;N
REVEL	Benign	0.024
Sift	Benign	0.078	T;T
Sift4G	Benign	0.077	T;D
Polyphen		0.028	B;.
Vest4		0.14
MutPred		0.28		Loss of helix (P = 0.0558);Loss of helix (P = 0.0558);
MVP		0.13
MPC		0.11
ClinPred		0.070	T
GERP RS		1.2
Varity_R		0.078
gMVP		0.39

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: rs542183778; hg19: chr20-1161967;