Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_000548.5(TSC2):c.1348G>A(p.Glu450Lys) variant causes a 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 Uncertain significance (★★).
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]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.E450K variant (also known as c.1348G>A), located in coding exon 12 of the TSC2 gene, results from a G to A substitution at nucleotide position 1348. The glutamic acid at codon 450 is replaced by lysine, an amino acid with similar properties. This variant was detected in a Greek child with TSC; however, this patient was also found to carry a known splicing c.3814+1G>A mutation in the TSC2 gene. Genetic analysis of the parents of this patient revealed that the father was a carrier of the c.1348G> variant and had no clinical signs of TSC (Papadopoulou A et al. Eur J Paediatr Neurol, 2018 May;22:419-426). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -