Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_020320.5(RARS2):c.1055dupA(p.His353AlafsTer15) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,748 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.
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]
RARS2 Gene-Disease associations (from GenCC):
mitochondrial disease
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
pontocerebellar hypoplasia type 6
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics, PanelApp Australia
complex neurodevelopmental disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
Our verdict: Pathogenic. The variant received 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 6-87520236-C-CT is Pathogenic according to our data. Variant chr6-87520236-C-CT is described in ClinVar as [Pathogenic]. Clinvar id is 1970672.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 1970672). This variant has not been reported in the literature in individuals affected with RARS2-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change creates a premature translational stop signal (p.His353Alafs*15) in the RARS2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in RARS2 are known to be pathogenic (PMID: 17847012, 22569581, 26083569). -