Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_177438.3(DICER1):c.1910_1911insGA(p.Tyr637fs) variant causes a frameshift, stop gained, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Y637Y) has been classified as Likely benign. 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]
DICER1 Gene-Disease associations (from GenCC):
DICER1-related tumor predisposition
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
pleuropulmonary blastoma
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
DICER1 syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Our verdict: Pathogenic. The variant received 12 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 14-95113221-G-GTC is Pathogenic according to our data. Variant chr14-95113221-G-GTC is described in ClinVar as Pathogenic. ClinVar VariationId is 820321.Status of the report is criteria_provided_single_submitter, 1 stars.
The c.1910_1911insGA pathogenic mutation, located in coding exon 11 of the DICER1 gene, results from an insertion of two nucleotides at position 1910, causing a translational frameshift with a predicted alternate stop codon (p.Y637*). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -