chr13-110677093-G-T

Position:

• chr13-110677093-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_024537.4(CARS2):​c.666C>A​(p.Asp222Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,454,774 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 nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CARS2 NM_024537.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.952

Genes affected

CARS2 (HGNC:25695): (cysteinyl-tRNA synthetase 2, mitochondrial) This gene encodes a putative member of the class I family of aminoacyl-tRNA synthetases. These enzymes play a critical role in protein biosynthesis by charging tRNAs with their cognate amino acids. This protein is encoded by the nuclear genome but is likely to be imported to the mitochondrion where it is thought to catalyze the ligation of cysteine to tRNA molecules. A splice-site mutation in this gene has been associated with a novel progressive myoclonic epilepsy disease with similar symptoms to MERRF syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.31387138).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CARS2	NM_024537.4	c.666C>A	p.Asp222Glu	missense_variant	7/15	ENST00000257347.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CARS2	ENST00000257347.9	c.666C>A	p.Asp222Glu	missense_variant	7/15	1	NM_024537.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1454774 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 722756

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000225

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.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Combined oxidative phosphorylation defect type 27 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 10, 2022

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. This sequence change replaces aspartic acid, which is acidic and polar, with glutamic acid, which is acidic and polar, at codon 222 of the CARS2 protein (p.Asp222Glu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CARS2-related conditions. ClinVar contains an entry for this variant (Variation ID: 938663). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.63
CADD	Benign	18
DANN	Benign	0.96
DEOGEN2	Benign	0.14	T
Eigen	Benign	-0.37
Eigen_PC	Benign	-0.19
FATHMM_MKL	Benign	0.47	N
LIST_S2	Benign	0.71	T
M_CAP	Benign	0.010	T
MetaRNN	Benign	0.31	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-0.42	N
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-1.8	N
REVEL	Benign	0.061
Sift	Benign	0.23	T
Sift4G	Benign	0.67	T
Polyphen		0.0080	B
Vest4		0.48
MutPred		0.42		Gain of ubiquitination at K223 (P = 0.1106);
MVP		0.36
MPC		0.17
ClinPred		0.67	D
GERP RS		4.4
Varity_R		0.089
gMVP		0.38

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: rs1555351973; hg19: chr13-111329440;