NM_000548.5:c.3259dupG

Variant names:

• chr16-2079398-C-CG
• rs137854302
• NM_000548.5:c.3259dupG

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000548.5(TSC2):​c.3259dupG​(p.Glu1087GlyfsTer81) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4 O:1
• Conservation: PhyloP100: -2.68

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 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-2079398-C-CG is Pathogenic according to our data. Variant chr16-2079398-C-CG is described in ClinVar as [Pathogenic]. Clinvar id is 50056.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.3259dupG	p.Glu1087GlyfsTer81	frameshift_variant	Exon 28 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.3259dupG	p.Glu1087GlyfsTer81	frameshift_variant	Exon 28 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:2

Nov 07, 2021

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 50056). This premature translational stop signal has been observed in individual(s) with TSC2-related conditions (PMID: 17304050, 21520333). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Glu1087Glyfs*81) in the TSC2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TSC2 are known to be pathogenic (PMID: 10205261, 17304050). -

Tuberous sclerosis 1 Pathogenic:1

Oct 14, 2021

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

_x000D_ Criteria applied: PVS1, PS4_MOD, PM2_SUP -

Hereditary cancer-predisposing syndrome Pathogenic:1

Oct 29, 2020

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.3259dupG (p.E1087Gfs*81) alteration, located in exon 28 (coding exon 27) of the TSC2 gene, consists of a duplication of G at position 3259, causing a translational frameshift with a predicted alternate stop codon after 81 amino acids. In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. In a cohort of individuals with clinical features of tuberous sclerosis (TSC), this mutation was identified in an individual with a diagnosis of TSC (Au, 2007). Based on the available evidence, this alteration is classified as pathogenic. -

Tuberous sclerosis syndrome Other:1

-

Tuberous sclerosis database (TSC2)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs137854302; hg19: chr16-2129399;