20-1181000-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001304748.2(TMEM74B):c.619C>T(p.Arg207Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000359 in 1,613,910 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: 𝑓 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000034 (0 hom.)
• Consequence: TMEM74B NM_001304748.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0410

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.749

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM74B	NM_001304748.2	c.619C>T	p.Arg207Trp	missense_variant	3/3	ENST00000429036.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM74B	ENST00000429036.2	c.619C>T	p.Arg207Trp	missense_variant	3/3	3	NM_001304748.2	P1
TMEM74B	ENST00000381894.3	c.619C>T	p.Arg207Trp	missense_variant	2/2	1		P1
PSMF1	ENST00000381898.5	c.243-5340G>A		intron_variant		3
PSMF1	ENST00000652336.1	c.*352G>A		3_prime_UTR_variant, NMD_transcript_variant	10/10

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152144 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000941

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000167 AC: 42 AN: 250992 Hom.: 0 AF XY: 0.000162 AC XY: 22 AN XY: 135744

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000839

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000490

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000463

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000335 AC: 49 AN: 1461766 Hom.: 0 Cov.: 31 AF XY: 0.0000344 AC XY: 25 AN XY: 727190

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000604

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.00000809

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000592 AC: 9 AN: 152144 Hom.: 0 Cov.: 32 AF XY: 0.0000673 AC XY: 5 AN XY: 74320

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000941

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000642

ExAC AF: 0.000124 AC: 15

EpiCase AF: 0.0000545

EpiControl AF: 0.00

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

Feb 26, 2024

The c.619C>T (p.R207W) alteration is located in exon 2 (coding exon 2) of the TMEM74B gene. This alteration results from a C to T substitution at nucleotide position 619, causing the arginine (R) at amino acid position 207 to be replaced by a tryptophan (W). 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	0.15
BayesDel_addAF	Benign	-0.074	T
BayesDel_noAF	Uncertain	0.040
Cadd	Uncertain	24
Dann	Pathogenic	1.0
DEOGEN2	Uncertain	0.45	T
Eigen	Benign	0.13
Eigen_PC	Benign	-0.040
FATHMM_MKL	Benign	0.25	N
LIST_S2	Uncertain	0.95	D
M_CAP	Benign	0.030	D
MetaRNN	Pathogenic	0.75	D
MetaSVM	Benign	-0.50	T
MutationAssessor	Uncertain	2.4	M
MutationTaster	Benign	0.99	D
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-6.6	D
REVEL	Uncertain	0.35
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.71
MutPred		0.71		Loss of disorder (P = 0.0309);
MVP		0.50
MPC		0.39
ClinPred		0.29	T
GERP RS		0.31
Varity_R		0.58
gMVP		0.75

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: rs746120459; hg19: chr20-1161644;