Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PVS1PS1PM2PP2PP5_Moderate
The NM_000368.5(TSC1):c.395_406delGCGTCTTGGTGTinsCA(p.Gly132fs) variant causes a frameshift, missense 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 (★). Another nucleotide change resulting in same amino acid change has been previously reported as Pathogenicin Lovd. Synonymous variant affecting the same amino acid position (i.e. G132G) 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 17 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PS1
Transcript NM_000368.5 (TSC1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in Lovd
PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TSC1. . Gene score misZ 2.3217 (greater than the threshold 3.09). Trascript score misZ 3.6986 (greater than threshold 3.09). GenCC has associacion of gene with lung lymphangioleiomyomatosis, tuberous sclerosis 1, tuberous sclerosis, tuberous sclerosis complex, lymphangioleiomyomatosis.
PP5
Variant 9-132923450-ACACCAAGACGC-TG is Pathogenic according to our data. Variant chr9-132923450-ACACCAAGACGC-TG is described in ClinVar as [Pathogenic]. Clinvar id is 49039.Status of the report is criteria_provided_single_submitter, 1 stars.
This sequence change creates a premature translational stop signal (p.Gly132Alafs*2) in the TSC1 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has been reported in individuals in the Leiden Open-source Variation Database (PMID: 21520333). Loss-of-function variants in TSC1 are known to be pathogenic (PMID: 10227394, 17304050). For these reasons, this variant has been classified as Pathogenic. -