chr16-2086208-G-A

Variant names:

• chr16-2086208-G-A
• rs777539610
• NM_000548.5:c.4678G>A

Variant summary

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

The NM_000548.5(TSC2):​c.4678G>A​(p.Ala1560Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,460,376 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. A1560P) 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 P:1 U:6 B:1
• Conservation: PhyloP100: 6.56
• 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 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 39 uncertain in NM_000548.5
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5	c.4678G>A	p.Ala1560Thr	missense_variant	Exon 37 of 42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.4678G>A	p.Ala1560Thr	missense_variant	Exon 37 of 42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249656 AF XY: 0.00000738

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460376 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726488

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52064

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111912

Other (OTH) AF: 0.0000166 AC: 1 AN: 60372

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000825 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:6 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Dec 27, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 18466115, 38256219)

Nov 03, 2021

Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Tuberous sclerosis 2 Uncertain:1 Benign:1

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Oct 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Ovarian cancer Pathogenic:1

Jan 01, 2022

Laboratory of Molecular Epidemiology of Birth Defects, West China Second University Hospital, Sichuan University

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Tuberous sclerosis syndrome Uncertain:1

Dec 01, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Isolated focal cortical dysplasia type II Uncertain:1

Feb 29, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 09, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A1560T variant (also known as c.4678G>A), located in coding exon 36 of the TSC2 gene, results from a G to A substitution at nucleotide position 4678. The alanine at codon 1560 is replaced by threonine, 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	Benign	0.19
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.53	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Uncertain	0.69	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Uncertain	2.2	M;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PhyloP100		6.6
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-1.8	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Pathogenic	0.70
Sift	Benign	0.057	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.13	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Vest4		0.75
ClinPred		0.89	D
GERP RS		4.5
Varity_R		0.70
gMVP		0.49
Mutation Taster		=67/33	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs777539610; hg19: chr16-2136209;