16-2088142-G-C

Position:

• chr16-2088142-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000548.5(TSC2):​c.5160+3G>C variant causes a splice donor region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 splice_donor_region, intron
• Scores: Splicing: ADA: 0.9959
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2 O:1
• Conservation: PhyloP100: 4.67

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.5160+3G>C		splice_donor_region_variant, intron_variant		ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.5160+3G>C		splice_donor_region_variant, intron_variant		5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 18, 2021

This sequence change falls in intron 40 of the TSC2 gene. It does not directly change the encoded amino acid sequence of the TSC2 protein. It affects a nucleotide within the consensus splice site of the intron. 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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has been observed in individual(s) with tuberous sclerosis complex (PMID: 16981987). ClinVar contains an entry for this variant (Variation ID: 49938). This variant is not present in population databases (ExAC no frequency). -

TSC2-related disorder Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Feb 16, 2023

The TSC2 c.5160+3G>C variant is predicted to interfere with splicing. This variant is predicted to alter splicing based on available splicing prediction programs (Alamut Visual Plus v1.6.1). However, the use of computer prediction programs is not equivalent to functional evidence. This variant has been reported in an individual with tuberous sclerosis complex (Table 2, Hung et al. 2006. PubMed ID: 16981987). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. It is interpreted as uncertain significance in ClinVar (https://preview.ncbi.nlm.nih.gov/clinvar/variation/49938/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

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_noAF	Benign	-0.55
CADD	Uncertain	24
DANN	Benign	0.77

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.73
SpliceAI score (max)		0.33		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.33		Position offset: 7

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

Publications

LitVar

Other links and lift over

dbSNP: rs45517401; hg19: chr16-2138143;