rs773023974

Variant names:

• chr22-46356875-G-T
• rs773023974
• NM_018006.5:c.1135G>T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_018006.5(TRMU):​c.1135G>T​(p.Gly379Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,132 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: TRMU NM_018006.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:3
• Conservation: PhyloP100: 8.84

Genes affected

TRMU (HGNC:25481): (tRNA mitochondrial 2-thiouridylase) This nuclear gene encodes a mitochondrial tRNA-modifying enzyme. The encoded protein catalyzes the 2-thiolation of uridine on the wobble positions of tRNA(Lys), tRNA(Glu), and tRNA(Gln), resulting in the formation of 5-taurinomethyl-2-thiouridine moieties. Mutations in this gene may cause transient infantile liver failure. Polymorphisms in this gene may also influence the severity of deafness caused by mitochondrial 12S ribosomal RNA mutations. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2013]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 22-46356875-G-T is Pathogenic according to our data. Variant chr22-46356875-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 193910.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=3, Likely_pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TRMU	NM_018006.5	c.1135G>T	p.Gly379Cys	missense_variant	Exon 11 of 11	ENST00000645190.1	NP_060476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TRMU	ENST00000645190.1	c.1135G>T	p.Gly379Cys	missense_variant	Exon 11 of 11		NM_018006.5	ENSP00000496496.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251018 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135796

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000145

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: 0.00000479 AC: 7 AN: 1461132 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726872

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000157

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.: 33

Bravo AF: 0.00000378

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	May 23, 2018	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 20, 2024	Published functional studies support this variant is associated with impaired mitochondrial protein synthesis (PMID: 38113276); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 25326635, 28973083, 37184518, 38113276) -

Inborn genetic diseases Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 28, 2017

- -

TRMU-related disorder Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Mar 20, 2024

The TRMU c.1135G>T variant is predicted to result in the amino acid substitution p.Gly379Cys. This variant was reported in the homozygous state or with a second TRMU variant in individuals with infantile liver failure (Meng et al 2017. PubMed ID: 28973083; Squires et al. 2023. PubMed ID: 37184518). This variant is reported in 0.014% of alleles in individuals of Latino descent in gnomAD. This variant is interpreted as likely pathogenic. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Dec 12, 2023

Variant summary: TRMU c.1135G>T (p.Gly379Cys) results in a non-conservative amino acid change located in the tRNA-specific 2-thiouridylase MnmA-like, C-terminal domain (IPR046885) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2e-05 in 251018 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1135G>T has been reported in the literature with a second variant (c.497C>A; p.Ala166Glu) in at least one individual affected with Liver Failure Acute Infantile, Transient (e.g. Meng_2017). This report does not provide unequivocal conclusions about association of the variant with Liver Failure Acute Infantile, Transient. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 28973083). Four submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 with conflicting assessments: two submitters classify the variant as likely pathogenic, and two submitters classify the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Acute infantile liver failure due to synthesis defect of mtDNA-encoded proteins Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Sep 01, 2017

This variant was found once in our laboratory with another variant (A166E; phase undetermined) in a 2-month-old female with liver failure & metabolic acidosis. Heterozygotes would be expected to be asymptomatic carriers. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.53	D;D
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	.;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Uncertain	0.32	D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-7.9	D;.
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0010	D;.
Sift4G	Pathogenic	0.0	D;.
Polyphen		1.0	D;D
Vest4		0.97
MutPred		0.94		Loss of glycosylation at S380 (P = 0.0631);Loss of glycosylation at S380 (P = 0.0631);
MVP		0.81
MPC		0.50
ClinPred		0.77	D
GERP RS		4.3
RBP_binding_hub_radar		0.97
RBP_regulation_power_radar		2.6
Varity_R		0.97
gMVP		0.86

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

Other links and lift over

dbSNP: rs773023974; hg19: chr22-46752772;