Genetic Variant NM_001304748.2:c.324G>C (chr20-1181295-C-G) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_001304748.2(TMEM74B):c.324G>C(p.Glu108Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,460,268 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: not found (cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

TMEM74B
NM_001304748.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -1.34

Variant links:

Genes affected

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

TMEM74B links:

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]

PSMF1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

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=0.015992314).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TMEM74B	NM_001304748.2 link	c.324G>C	p.Glu108Asp	missense_variant	Exon 3 of 3	ENST00000429036.2	NP_001291677.1	Q9NUR3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TMEM74B	ENST00000429036.2 link	c.324G>C	p.Glu108Asp	missense_variant	Exon 3 of 3	3	NM_001304748.2	ENSP00000400552.2		Q9NUR3Q5QPM3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

249384

Hom.:

AF XY:

0.0000148

AC XY:

AN XY:

134716

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000872

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:

0.00000274

AC:

AN:

1460268

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726306

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000897

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000756

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Mar 11, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.324G>C (p.E108D) alteration is located in exon 2 (coding exon 2) of the TMEM74B gene. This alteration results from a G to C substitution at nucleotide position 324, causing the glutamic acid (E) at amino acid position 108 to be replaced by an aspartic acid (D). 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

0.091

BayesDel_addAF

Benign

-0.46

BayesDel_noAF

Benign

-0.70

CADD

Benign

DANN

Uncertain

0.97

DEOGEN2

Benign

0.013

T;T

Eigen

Benign

-0.82

Eigen_PC

Benign

-0.69

FATHMM_MKL

Benign

0.17

LIST_S2

Benign

0.62

T;T

M_CAP

Benign

0.0034

MetaRNN

Benign

0.016

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

-1.1

N;.

PrimateAI

Benign

0.47

PROVEAN

Benign

0.49

N;N

REVEL

Benign

0.072

Sift

Benign

0.73

T;T

Sift4G

Benign

0.84

T;T

Polyphen

0.035

B;.

Vest4

0.14

MutPred

0.19

Loss of catalytic residue at E108 (P = 0.0605);Loss of catalytic residue at E108 (P = 0.0605);

MVP

0.048

MPC

0.075

ClinPred

0.14

GERP RS

2.1

Varity_R

0.076

gMVP

0.32

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over