Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_000368.5(TSC1):c.555C>G(p.Tyr185*) variant causes a stop gained change involving the alteration of a non-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. Y185Y) has been classified as Benign. Variant results in nonsense mediated mRNA decay.
TSC1 (HGNC:12362): (TSC complex subunit 1) This gene is a tumor suppressor gene that encodes the growth inhibitory protein hamartin. The encoded protein interacts with and stabilizes the GTPase activating protein tuberin. This hamartin-tuberin complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. This protein also functions as a co-chaperone for Hsp90 that inhibits its ATPase activity. This protein functions as a facilitator of Hsp90-mediated folding of kinase and non-kinase clients, including TSC2 and thereby preventing their ubiquitination and proteasomal degradation. 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 9-132921927-G-C is Pathogenic according to our data. Variant chr9-132921927-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 653437.Status of the report is criteria_provided_single_submitter, 1 stars.
This variant is not present in population databases (ExAC no frequency). For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). This variant has not been reported in the literature in individuals with TSC1-related disease. This sequence change creates a premature translational stop signal (p.Tyr185*) in the TSC1 gene. It is expected to result in an absent or disrupted protein product. -