rs45517263

chr16-2076490-G-Achr16-2076490-G-Cchr16-2076490-G-T

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1 PM2 PP3_Strong PP5_Very_Strong

The NM_000548.5(TSC2):c.2743-1G>A variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC2 NM_000548.5 splice_acceptor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.36

Genes affected

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]

ACMG classification

Verdict is Pathogenic. Variant got 22 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 16-2076490-G-A is Pathogenic according to our data. Variant chr16-2076490-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 49560.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-2076490-G-A is described in Lovd as [Pathogenic]. Variant chr16-2076490-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.2743-1G>A		splice_acceptor_variant		ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.2743-1G>A		splice_acceptor_variant		5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Feb 01, 2018

This variant has been reported in individuals in the Leiden Open-source Variation Database (PMID: 21520333). Additionally, a different variant affecting this nucleotide (c.2743-1G>C, also reported as c.2761-1G>C) has been reported in an individual affected with tuberous sclerosis (PMID: 12111193).ClinVar contains an entry for this variant (Variation ID: 49560). This sequence change affects an acceptor splice site in intron 24 of the TSC2 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in TSC2 are known to be pathogenic (PMID: 10205261, 17304050). For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 19, 2018

The c.2743-1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide upstream from coding exon 24 of the TSC2 gene. This mutation was identified in an individual with seizures, skin findings including hypomelanotic macules, facial angiofibromas, confetti like hypopigmented macules, and shagreen patches, adenoma sebaceum, and ungual fibromas. In addition, a cell line from this individual demonstrated radiosensitivity (Au KS et al. Genet. Med., 2007 Feb;9:88-100; Ferlazzo ML et al. Mol. Neurobiol., 2018 Jun;55:4973-4983). Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Tuberous sclerosis syndrome Other:1

not provided, no classification provided

curation

Tuberous sclerosis database (TSC2)

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.060
Cadd	Pathogenic	35
Dann	Uncertain	0.99
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.97	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
GERP RS		3.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.87		Position offset: 2
DS_AL_spliceai		0.99		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs45517263; hg19: chr16-2126491;