Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2
The NM_000548.5(TSC2):c.4663A>G(p.Ser1555Gly) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,106 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predict no significant impact on normal splicing. 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
This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 1555 of the TSC2 protein (p.Ser1555Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 1346900). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.S1555G variant (also known as c.4663A>G) is located in coding exon 36 of the TSC2 gene. The serine at codon 1555 is replaced by glycine, an amino acid with similar properties. This change occurs in the first base pair of coding exon 36. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -