2-197705428-G-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_138395.4(MARS2):c.23G>T(p.Arg8Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000174 in 1,611,140 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R8S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000016 (0 hom.)
• Consequence: MARS2 NM_138395.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.12

Genes affected

MARS2 (HGNC:25133): (methionyl-tRNA synthetase 2, mitochondrial) This gene produces a mitochondrial methionyl-tRNA synthetase protein that is encoded by the nuclear genome and imported to the mitochondrion. This protein likely functions as a monomer and is predicted to localize to the mitochondrial matrix. Mutations in this gene are associated with the autosomal recessive neurodegenerative disease spastic ataxia-3 (SPAX3). [provided by RefSeq, Apr 2014]

(HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.01891452).
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.0000263 (4/152220) while in subpopulation EAS AF= 0.00077 (4/5196). AF 95% confidence interval is 0.000263. There are 0 homozygotes in gnomad4. There are 3 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MARS2	NM_138395.4	c.23G>T	p.Arg8Leu	missense_variant	1/1	ENST00000282276.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MARS2	ENST00000282276.8	c.23G>T	p.Arg8Leu	missense_variant	1/1		NM_138395.4	P1
	ENST00000409845.1	n.166+6564G>T		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152220 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000770

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000118 AC: 29 AN: 245314 Hom.: 0 AF XY: 0.0000971 AC XY: 13 AN XY: 133832

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00159

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: 0.0000165 AC: 24 AN: 1458920 Hom.: 0 Cov.: 31 AF XY: 0.0000138 AC XY: 10 AN XY: 725728

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000479

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.0000498

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152220 Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3 AN XY: 74378

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000770

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000264

ExAC AF: 0.000132 AC: 16

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 04, 2023

This variant is present in population databases (rs751636540, gnomAD 0.2%), and has an allele count higher than expected for a pathogenic variant. This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 8 of the MARS2 protein (p.Arg8Leu). This variant has not been reported in the literature in individuals affected with MARS2-related conditions. ClinVar contains an entry for this variant (Variation ID: 1421018). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.47	T
BayesDel_noAF	Benign	-0.47
Cadd	Benign	16
Dann	Benign	0.89
DEOGEN2	Benign	0.11	T
Eigen	Benign	-0.58
Eigen_PC	Benign	-0.48
FATHMM_MKL	Benign	0.74	D
LIST_S2	Benign	0.58	T
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.019	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.0	N
MutationTaster	Benign	1.0	N
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.83	N
REVEL	Benign	0.10
Sift	Benign	0.052	T
Sift4G	Benign	0.16	T
Polyphen		0.0010	B
Vest4		0.30
MutPred		0.43		Loss of MoRF binding (P = 0.0022);
MVP		0.60
MPC		0.53
ClinPred		0.061	T
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.0
Varity_R		0.17
gMVP		0.50

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: rs751636540; hg19: chr2-198570152;