16-2079586-C-T

Variant names:

• chr16-2079586-C-T
• rs946381749
• NM_000548.5:c.3314C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000548.5(TSC2):​c.3314C>T​(p.Thr1105Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,459,316 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1105A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 3.60
• 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]

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.38529837).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.3314C>T	p.Thr1105Ile	missense_variant	Exon 29 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.3314C>T	p.Thr1105Ile	missense_variant	Exon 29 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459316 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 725860

African (AFR) AF: 0.0000299 AC: 1 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44566

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26088

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39640

South Asian (SAS) AF: 0.00 AC: 0 AN: 86052

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51968

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111518

Other (OTH) AF: 0.00 AC: 0 AN: 60254

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000113

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Tuberous sclerosis syndrome Uncertain:1

Sep 17, 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 threonine with isoleucine at codon 1105 of the TSC2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, 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 not been identified 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. -

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

Oct 20, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Apr 17, 2023

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 -

Hereditary cancer-predisposing syndrome Uncertain:1

May 04, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T1105I variant (also known as c.3314C>T), located in coding exon 28 of the TSC2 gene, results from a C to T substitution at nucleotide position 3314. The threonine at codon 1105 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. 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. -

Tuberous sclerosis 2 Benign:1

Jan 01, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Benign	23
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.69	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.0048
Eigen_PC	Benign	0.066
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.81	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
M_CAP	Uncertain	0.15	D
MetaRNN	Benign	0.39	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.63	D
MutationAssessor	Benign	1.6	L;.;.;.;.;.;.;.;.;L;.;.;.;.;.
PhyloP100		3.6
PrimateAI	Uncertain	0.70	T
PROVEAN	Uncertain	-3.0	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Uncertain	0.58
Sift	Benign	0.087	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Uncertain	0.042	D;.;.;T;.;T;.;.;T;D;.;.;.;.;T
Polyphen		1.0	D;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4		0.44
MutPred		0.19		Loss of loop (P = 0.0073);.;Loss of loop (P = 0.0073);.;.;.;.;Loss of loop (P = 0.0073);.;Loss of loop (P = 0.0073);.;.;.;.;.;
MVP		0.81
ClinPred		0.83	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.094
gMVP		0.40
Mutation Taster		=56/44	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: rs946381749; hg19: chr16-2129587;