Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_000548.5(TSC2):c.421G>T(p.Glu141Ter) variant causes a stop gained 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. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. E141E) has been classified as Likely benign. 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 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 16-2054380-G-T is Pathogenic according to our data. Variant chr16-2054380-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 405985.Status of the report is criteria_provided_single_submitter, 1 stars.
While this particular variant has not been reported in the literature, loss-of-function variants in TSC2 are known to be pathogenic (PMID: 10205261, 17304050). This sequence change creates a premature translational stop signal at codon 141 (p.Glu141*) of the TSC2 gene. It is expected to result in an absent or disrupted protein product. For these reasons, this variant has been classified as Pathogenic. -