Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2PP3_StrongPP5_Moderate
The NM_001406626.1(TSC1):c.-143C>G variant causes a 5 prime UTR premature start codon gain 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 (★).
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 Likely_pathogenic. Variant got 8 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
PP3
BayesDel_addAF computational evidence supports a deleterious effect, 0.622
PP5
Variant 9-132912386-G-C is Pathogenic according to our data. Variant chr9-132912386-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 2034327.Status of the report is criteria_provided_single_submitter, 1 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals affected with TSC1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Ser270*) in the TSC1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). -