Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000548.5(TSC2):c.569dupA(p.Tyr190fs) variant causes a frameshift, stop gained 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 (★★). Variant results in nonsense mediated mRNA decay.
TSC2 (HGNC:12363): (TSC complex subunit 2) This gene is a tumor suppressor gene that encodes the growth inhibitory protein tuberin. Tuberin interacts with hamartin to form the TSC protein complex which functions in the control of cell growth. This TSC protein complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]
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 16-2055488-T-TA is Pathogenic according to our data. Variant chr16-2055488-T-TA is described in ClinVar as [Pathogenic]. Clinvar id is 50038.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Nov 07, 2021
Genome-Nilou Lab
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Nov 12, 2019
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in TSC2 are known to be pathogenic (PMID: 10205261, 17304050). This variant has been observed in individual(s) with tuberous sclerosis complex (PMID: 10735580). It is also known as 570insA in the literature. ClinVar contains an entry for this variant (Variation ID: 50038). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Tyr190*) in the TSC2 gene. It is expected to result in an absent or disrupted protein product. -