1-173825235-C-G

Variant names:

• chr1-173825235-C-G
• rs2102629804
• NM_018122.5:c.6C>G

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_018122.5(DARS2):​c.6C>G​(p.Tyr2*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: DARS2 NM_018122.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.0540
• Publications: 0 publications found

Genes affected

DARS2 (HGNC:25538): (aspartyl-tRNA synthetase 2, mitochondrial) The protein encoded by this gene belongs to the class-II aminoacyl-tRNA synthetase family. It is a mitochondrial enzyme that specifically aminoacylates aspartyl-tRNA. Mutations in this gene are associated with leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). [provided by RefSeq, Nov 2009]

DARS2 Gene-Disease associations (from GenCC):

• leukoencephalopathy with brain stem and spinal cord involvement-high lactate syndrome

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, Orphanet
• mitochondrial disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 63 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-173825235-C-G is Pathogenic according to our data. Variant chr1-173825235-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 1453218.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DARS2	NM_018122.5	c.6C>G	p.Tyr2*	stop_gained	Exon 1 of 17	ENST00000649689.2	NP_060592.2
DARS2	NM_001365212.1	c.6C>G	p.Tyr2*	stop_gained	Exon 1 of 16		NP_001352141.1
DARS2	NM_001365213.2	c.6C>G	p.Tyr2*	stop_gained	Exon 1 of 14		NP_001352142.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DARS2	ENST00000649689.2	c.6C>G	p.Tyr2*	stop_gained	Exon 1 of 17		NM_018122.5	ENSP00000497569.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Dec 02, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Tyr2*) in the DARS2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in DARS2 are known to be pathogenic (PMID: 17384640, 24566671). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with DARS2-related conditions. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Benign	0.012
Eigen_PC	Benign	-0.32
FATHMM_MKL	Benign	0.078	N
PhyloP100		-0.054
Vest4		0.34
GERP RS		1.9
PromoterAI		-0.13	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Mutation Taster		=44/156	disease causing (fs/PTC)

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

Other links and lift over

dbSNP: rs2102629804; hg19: chr1-173794373;