Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_001406629.1(TSC1):c.-106C>A variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).
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]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TSC1-related disease. This sequence change replaces leucine with methionine at codon 330 of the TSC1 protein (p.Leu330Met). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and methionine. -
Loss of catalytic residue at L330 (P = 0.0436);.;Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);.;.;Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);Loss of catalytic residue at L330 (P = 0.0436);.;Loss of catalytic residue at L330 (P = 0.0436);