NM_000548.5:c.3212C>T

Variant names:

• chr16-2079356-C-T
• rs45498892
• NM_000548.5:c.3212C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 6P and 4B. PM1 PM5 PP3_Moderate BS2

The NM_000548.5(TSC2):​c.3212C>T​(p.Thr1071Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,460,684 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. T1071A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 7.57
• Publications: 6 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 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 11 benign, 28 uncertain in NM_000548.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-2079356-C-G is described in ClinVar as Pathogenic. ClinVar VariationId is 49247.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.913
• BS2: High AC in GnomAdExome4 at 19 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.3212C>T	p.Thr1071Ile	missense_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.3212C>T	p.Thr1071Ile	missense_variant	Exon 28 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000130 AC: 19 AN: 1460684 Hom.: 0 Cov.: 31 AF XY: 0.0000193 AC XY: 14 AN XY: 726624

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52236

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000171 AC: 19 AN: 1112002

Other (OTH) AF: 0.00 AC: 0 AN: 60382

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 1071 of the TSC2 protein (p.Thr1071Ile). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 406076). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on TSC2 protein function. This variant disrupts the p.Thr1071 amino acid residue in TSC2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 1112665). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

not provided Uncertain:2

Dec 02, 2022

GeneDx

Significance: Uncertain significance

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; Has not been previously published as pathogenic or benign to our knowledge -

Aug 24, 2017

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Jul 16, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T1071I variant (also known as c.3212C>T), located in coding exon 27 of the TSC2 gene, results from a C to T substitution at nucleotide position 3212. The threonine at codon 1071 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.50
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.91	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Uncertain	2.8	M;.;.;.;.;.;.;.;.;M;.;.;.;.;.
PhyloP100		7.6
PrimateAI	Pathogenic	0.80	D
PROVEAN	Pathogenic	-5.7	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.0020	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		1.0	D;.;.;.;D;D;.;.;D;D;.;.;.;.;.
Vest4		0.97
MutPred		0.52		Loss of disorder (P = 0.0172);.;Loss of disorder (P = 0.0172);.;.;.;.;Loss of disorder (P = 0.0172);.;Loss of disorder (P = 0.0172);.;.;.;.;.;
MVP		0.97
ClinPred		1.0	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.84
gMVP		0.92
Mutation Taster		=17/83	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: rs45498892; hg19: chr16-2129357;