chr16-2079361-G-T

Variant names:

• chr16-2079361-G-T
• rs749192298
• NM_000548.5:c.3217G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000548.5(TSC2):​c.3217G>T​(p.Val1073Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,186 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V1073M) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.57
• Publications: 3 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: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 8 benign, 27 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage

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.3217G>T	p.Val1073Leu	missense	Exon 28 of 42	NP_000539.2
	TSC2	NM_001406663.1		c.3214G>T	p.Val1072Leu	missense	Exon 28 of 42	NP_001393592.1
	TSC2	NM_001114382.3		c.3217G>T	p.Val1073Leu	missense	Exon 28 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.3217G>T	p.Val1073Leu	missense	Exon 28 of 42	ENSP00000219476.3
	TSC2	ENST00000350773.9	TSL:1	c.3217G>T	p.Val1073Leu	missense	Exon 28 of 41	ENSP00000344383.4
	TSC2	ENST00000401874.7	TSL:1	c.3085G>T	p.Val1029Leu	missense	Exon 27 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152186 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152186 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74336

African (AFR) AF: 0.0000241 AC: 1 AN: 41452

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10618

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68032

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Jun 26, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces valine with leucine at codon 1073 of the TSC2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with tuberous sclerosis complex in the literature. This variant has been identified in 1/31360 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Hereditary cancer-predisposing syndrome Uncertain:1

Sep 13, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.V1073L variant (also known as c.3217G>T), located in coding exon 27 of the TSC2 gene, results from a G to T substitution at nucleotide position 3217. The valine at codon 1073 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.51	D
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.20	D
MetaRNN	Uncertain	0.52	D
MetaSVM	Uncertain	0.46	D
MutationAssessor	Benign	1.4	L
PhyloP100		9.6
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-1.3	N
REVEL	Uncertain	0.49
Sift	Benign	0.18	T
Sift4G	Benign	0.098	T
Polyphen		0.97	D
Vest4		0.53
MutPred		0.23		Loss of MoRF binding (P = 0.1005)
MVP		0.88
ClinPred		0.77	D
GERP RS		3.7
Varity_R		0.15
gMVP		0.68
Mutation Taster		=80/20	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs749192298; hg19: chr16-2129362;