Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3PP5_Moderate
The ENST00000439117.6(TSC2):n.*2808_*2981+28del variant causes a splice region, non coding transcript exon change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Pathogenic (★).
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]
TSC2 Gene-Disease associations (from GenCC):
tuberous sclerosis
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
tuberous sclerosis 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
lymphangioleiomyomatosis
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
tuberous sclerosis complex
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
PP3
No computational evidence supports a deleterious effect, but strongly conserved according to phyloP
PP5
Variant 16-2081624-AACCCGCTCAGCCCTTTCTCCTCGGACATCAACAACATGCCCCTGCAGGAGCTGTCTAACGCCCTCATGGCGGCTGAGCGCTTCAAGGAGCACCGGGACACAGCCCTGTACAAGTCACTGTCGGTGCCGGCAGCCAGCACGGCCAAACCCCCTCCTCTGCCTCGCTCCAACACAGGTGAGTGGCATGGCGGGCCTTGGCACGG-A is Pathogenic according to our data. Variant chr16-2081624-AACCCGCTCAGCCCTTTCTCCTCGGACATCAACAACATGCCCCTGCAGGAGCTGTCTAACGCCCTCATGGCGGCTGAGCGCTTCAAGGAGCACCGGGACACAGCCCTGTACAAGTCACTGTCGGTGCCGGCAGCCAGCACGGCCAAACCCCCTCCTCTGCCTCGCTCCAACACAGGTGAGTGGCATGGCGGGCCTTGGCACGG-A is described in ClinVar as [Pathogenic]. Clinvar id is 535979.Status of the report is criteria_provided_single_submitter, 1 stars.
This variant is a gross deletion of the genomic region encompassing part of exon 31 of the TSC2 gene including the exon 31-intron 31 boundary (c.3641_3814+28del). This is expected to create a premature translational stop signal and result in an absent or disrupted protein product. Similar deletions have not been reported in the literature in individuals with TSC2-related disease. Loss-of-function variants in TSC2 are known to be pathogenic (PMID: 10205261, 17304050). For these reasons, this variant has been classified as Pathogenic. -