16-2086825-T-C

Variant names:

• chr16-2086825-T-C
• rs45471896
• NM_000548.5:c.4943T>C

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000548.5(TSC2):​c.4943T>C​(p.Ile1648Thr) variant causes a missense 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. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1648L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4 O:1
• Conservation: PhyloP100: 7.92
• Publications: 5 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]

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

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 32 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 16-2086825-T-C is Pathogenic according to our data. Variant chr16-2086825-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 49458.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 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.4943T>C	p.Ile1648Thr	missense	Exon 38 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.4940T>C	p.Ile1647Thr	missense	Exon 38 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.4874T>C	p.Ile1625Thr	missense	Exon 37 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.4943T>C	p.Ile1648Thr	missense	Exon 38 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.4874T>C	p.Ile1625Thr	missense	Exon 37 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.4742T>C	p.Ile1581Thr	missense	Exon 36 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Pathogenic:2

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Absent from controls (or at extremely low frequency if recessive) in Genome Aggregation Database, Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium.;Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc).;The prevalence of the variant in affected individuals is significantly increased compared to the prevalence in controls.;Assumed de novo, but without confirmation of paternity and maternity.;Patient's phenotype or family history is highly specific for a disease with a single genetic etiology.

May 05, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 1648 of the TSC2 protein (p.Ile1648Thr). This variant is not present in population databases (gnomAD no frequency). For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TSC2 protein function. ClinVar contains an entry for this variant (Variation ID: 49458). This missense change has been observed in individual(s) with tuberous sclerosis complex (PMID: 11112665, 32211034). In at least one individual the variant was observed to be de novo.

Lymphangiomyomatosis;C1846385:Isolated focal cortical dysplasia type II;C1860707:Tuberous sclerosis 2 Pathogenic:1

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TSC2 NM_000548.4 exon 38 p.Ile1648Thr (c.4943T>C): This variant has been reported in the literature in at least 1 individual with Tuberous sclerosis (Dabora 2001 PMID:11112665). This variant is not present in large control databases. This variant is present in ClinVar (Variation ID:49458). Evolutionary conservation and computational predictive tools suggest that this variant may impact the protein. Parental testing has indicated that this variant is found to be de novo in this patient. Therefore this variant is classified as likely pathogenic.

not provided Pathogenic:1

Feb 17, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 26540169, 11112665, 18466115, 32211034)

Tuberous sclerosis syndrome Other:1

Tuberous sclerosis database (TSC2)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	0.74
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		7.9
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-4.2	D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0050	D
Polyphen		1.0	D
Vest4		0.81
MutPred		0.94		Gain of disorder (P = 0.043)
MVP		0.98
ClinPred		0.99	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.95
gMVP		0.92
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs45471896; hg19: chr16-2136826;