Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_020320.5(RARS2):c.1054_1055delAA(p.Lys352AlafsTer15) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely 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]
Verdict is Pathogenic. Variant got 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-CTT-C is Pathogenic according to our data. Variant chr6-87520236-CTT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 212016.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 212016). This variant has not been reported in the literature in individuals affected with RARS2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Lys352Alafs*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). -
Pontocerebellar hypoplasia type 6 Pathogenic:1
Aug 14, 2014
Genetic Services Laboratory, University of Chicago
Significance: Likely pathogenic
Review Status: criteria provided, single submitter