NM_000548.5:c.5281_5296delTCCAACCCCAGCCTAC

Variant names:

• chr16-2088460-CGCCTACTCCAACCCCA-C
• rs1064792923
• NM_000548.5:c.5281_5296delTCCAACCCCAGCCTAC

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Strong PP5_Moderate

The NM_000548.5(TSC2):​c.5281_5296delTCCAACCCCAGCCTAC​(p.Ser1761LeufsTer60) variant causes a frameshift change involving the alteration of a non-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 (★). Synonymous variant affecting the same amino acid position (i.e. S1761S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.27
• Publications: 2 publications found

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]

PKD1 (HGNC:9008): (polycystin 1, transient receptor potential channel interacting) This gene encodes a member of the polycystin protein family. The encoded glycoprotein contains a large N-terminal extracellular region, multiple transmembrane domains and a cytoplasmic C-tail. It is an integral membrane protein that functions as a regulator of calcium permeable cation channels and intracellular calcium homoeostasis. It is also involved in cell-cell/matrix interactions and may modulate G-protein-coupled signal-transduction pathways. It plays a role in renal tubular development, and mutations in this gene cause autosomal dominant polycystic kidney disease type 1 (ADPKD1). ADPKD1 is characterized by the growth of fluid-filled cysts that replace normal renal tissue and result in end-stage renal failure. Splice variants encoding different isoforms have been noted for this gene. Also, six pseudogenes, closely linked in a known duplicated region on chromosome 16p, have been described. [provided by RefSeq, Oct 2008]

PKD1 Gene-Disease associations (from GenCC):

• autosomal dominant polycystic kidney disease

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• polycystic kidney disease 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• autosomal recessive polycystic kidney disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Caroli disease

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 11 pathogenic variants in the truncated region.
• PP5: Variant 16-2088460-CGCCTACTCCAACCCCA-C is Pathogenic according to our data. Variant chr16-2088460-CGCCTACTCCAACCCCA-C is described in ClinVar as Pathogenic. ClinVar VariationId is 406134.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000548.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	NM_000548.5	MANE Select	c.5281_5296delTCCAACCCCAGCCTAC	p.Ser1761LeufsTer60	frameshift	Exon 42 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.5278_5293delTCCAACCCCAGCCTAC	p.Ser1760LeufsTer60	frameshift	Exon 42 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.5212_5227delTCCAACCCCAGCCTAC	p.Ser1738LeufsTer60	frameshift	Exon 41 of 41	NP_001107854.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TSC2	ENST00000219476.9	TSL:5 MANE Select	c.5281_5296delTCCAACCCCAGCCTAC	p.Ser1761LeufsTer60	frameshift	Exon 42 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.5212_5227delTCCAACCCCAGCCTAC	p.Ser1738LeufsTer60	frameshift	Exon 41 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.5080_5095delTCCAACCCCAGCCTAC	p.Ser1694LeufsTer60	frameshift	Exon 40 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:1

Oct 03, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change deletes 16 nucleotides in exon 42 of the TSC2 mRNA (c.5281_5296delTCCAACCCCAGCCTAC), causing a frameshift at codon 1761. This creates a premature translational stop signal in the last exon of the TSC2 mRNA (p.Ser1761Leufs*60). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 47 amino acids of the TSC2 protein. This variant has been reported in an individual with tuberous sclerosis complex (TSC) in the Leiden Open-source Variation Database (PMID: 21520333, 25498131). Multiple frameshift variants including c.5340_5371del (p.1784Alafs*?) and c.5405_5408dup (p.Phe1803Leufs*42), located downstream of this variant have been reported as disease-causing de novo variants in individuals affected with TSC (PMID: 10205261, 9328481, 24789117), suggesting that frameshift variants affecting the very C-terminal of TSC2 impact protein function and cause disease. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.3
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1064792923; hg19: chr16-2138461;