Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1PM2PP3PP5_Very_Strong
The NM_177438.3(DICER1):c.901C>T(p.Gln301*) variant causes a stop gained, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.
DICER1 (HGNC:17098): (dicer 1, ribonuclease III) This gene encodes a protein possessing an RNA helicase motif containing a DEXH box in its amino terminus and an RNA motif in the carboxy terminus. The encoded protein functions as a ribonuclease and is required by the RNA interference and small temporal RNA (stRNA) pathways to produce the active small RNA component that represses gene expression. This protein also acts as a strong antiviral agent with activity against RNA viruses, including the Zika and SARS-CoV-2 viruses. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2021]
Verdict is Pathogenic. Variant got 19 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;
PP3
Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
PP5
Variant 14-95126582-G-A is Pathogenic according to our data. Variant chr14-95126582-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 477292.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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DICER1-related tumor predisposition Pathogenic:1
Jul 21, 2017
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.Gln301*) in the DICER1 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with DICER1-related disease. Loss-of-function variants in DICER1 are known to be pathogenic (PMID: 19556464, 21266384). For these reasons, this variant has been classified as Pathogenic. -