6-87589957-T-G

Variant names:

• chr6-87589957-T-G
• rs774923951
• NM_020320.5:c.1A>C

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PS1_Moderate PP5_Very_Strong

The NM_020320.5(RARS2):​c.1A>C​(p.Met1?) variant causes a initiator codon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,092 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: RARS2 NM_020320.5 initiator_codon
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.90
• Publications: 8 publications found

Genes affected

RARS2 (HGNC:21406): (arginyl-tRNA synthetase 2, mitochondrial) This nuclear gene encodes a protein that localizes to the mitochondria, where it catalyzes the transfer of L-arginine to its cognate tRNA, an important step in translation of mitochondrially-encoded proteins. Defects in this gene are a cause of pontocerebellar hypoplasia type 6 (PCH6). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

ORC3 (HGNC:8489): (origin recognition complex subunit 3) The origin recognition complex (ORC) is a highly conserved six subunits protein complex essential for the initiation of the DNA replication in eukaryotic cells. Studies in yeast demonstrated that ORC binds specifically to origins of replication and serves as a platform for the assembly of additional initiation factors such as Cdc6 and Mcm proteins. The protein encoded by this gene is a subunit of the ORC complex. Studies of a similar gene in Drosophila suggested a possible role of this protein in neuronal proliferation and olfactory memory. Alternatively spliced transcript variants encoding distinct isoforms have been reported for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 62 pathogenic variants. Next in-frame start position is after 176 codons. Genomic position: 87545625. Lost 0.303 part of the original CDS.
• PS1: Another start lost variant in NM_020320.5 (RARS2) was described as [Pathogenic] in ClinVar as 1070705
• PP5: Variant 6-87589957-T-G is Pathogenic according to our data. Variant chr6-87589957-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1457359.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RARS2	NM_020320.5	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 20	ENST00000369536.10	NP_064716.2
ORC3	NM_012381.4	c.-212T>G		upstream_gene_variant		ENST00000392844.8	NP_036513.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RARS2	ENST00000369536.10	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 20	1	NM_020320.5	ENSP00000358549.5
ORC3	ENST00000392844.8	c.-212T>G		upstream_gene_variant		1	NM_012381.4	ENSP00000376586.3

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152222 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 250932 AF XY: 0.0000294

Gnomad AFR exome AF: 0.0000623

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461870 Hom.: 0 Cov.: 33 AF XY: 0.00000688 AC XY: 5 AN XY: 727236

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152222 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74376

African (AFR) AF: 0.0000482 AC: 2 AN: 41468

American (AMR) AF: 0.00 AC: 0 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000189

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Mar 09, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is present in population databases (rs774923951, gnomAD 0.004%). Disruption of the initiator codon has been observed in individual(s) with pontocerebellar hypoplasia (PMID: 26083569, 26795593, 32860008). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 1457359). This variant disrupts a region of the RARS2 protein in which other variant(s) (p.Lys158del) have been determined to be pathogenic (PMID: 22086604, 27061686). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. This sequence change affects the initiator methionine of the RARS2 mRNA. The next in-frame methionine is located at codon 176. -

Pontocerebellar hypoplasia type 6 Pathogenic:1

Feb 15, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.38
CADD	Benign	21
DANN	Benign	0.88
DEOGEN2	Benign	0.017	T
Eigen	Benign	-0.17
Eigen_PC	Benign	-0.092
FATHMM_MKL	Benign	0.45	N
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Benign	-0.84	T
PhyloP100		1.9
PROVEAN	Benign	-0.69	N
REVEL	Uncertain	0.38
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.15	B
Vest4		0.84
MutPred		0.95		Loss of catalytic residue at M1 (P = 2e-04);
MVP		0.71
ClinPred		1.0	D
GERP RS		4.0
PromoterAI		-0.56	Under-expression
Varity_R		0.96
gMVP		0.63
Mutation Taster		=4/196	disease causing

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: rs774923951; hg19: chr6-88299675;