16-2085244-G-T

Position:

• chr16-2085244-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000548.5(TSC2):​c.4584G>T​(p.Glu1528Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,410 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: -0.109

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.4584G>T	p.Glu1528Asp	missense_variant	36/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.4584G>T	p.Glu1528Asp	missense_variant	36/42	5	NM_000548.5	ENSP00000219476.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460410 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 726506

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 03, 2024	This sequence change replaces glutamic acid, which is acidic and polar, with aspartic acid, which is acidic and polar, at codon 1528 of the TSC2 protein (p.Glu1528Asp). 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: 41743). 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 not expected to disrupt TSC2 protein function with a negative predictive value of 95%. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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:1

Uncertain significance, no assertion criteria provided

research

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Jul 13, 2012

- -

Isolated focal cortical dysplasia type II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Jul 11, 2023

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 20, 2023

The p.E1528D variant (also known as c.4584G>T), located in coding exon 35 of the TSC2 gene, results from a G to T substitution at nucleotide position 4584. The glutamic acid at codon 1528 is replaced by aspartic acid, an amino acid with highly similar properties. This variant was detected as a secondary finding in 1 out of 572 ClinSeq participants, unselected for personal or family history of cancer, who underwent exome sequencing; however, the clinical information for this particular individual was not provided (Johnston JJ et al. Am. J. Hum. Genet., 2012 Jul;91:97-108). This amino acid position is well conserved in available vertebrate species. In addition, as a missense variant, this alteration is predicted to be tolerated by in silico analysis. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data).. 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	0.12
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.39	T;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.62
Eigen_PC	Benign	-0.54
FATHMM_MKL	Benign	0.53	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.20	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.070	T
MutationAssessor	Benign	0.23	N;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.68	T
PROVEAN	Benign	-0.48	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.57
Sift	Benign	0.37	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G	Benign	0.63	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.26	B;.;.;.;B;B;.;.;D;B;.;.;.;.;.
Vest4		0.46
MutPred		0.37		Loss of helix (P = 0.0196);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.94
ClinPred		0.45	T
GERP RS		-0.060
Varity_R		0.077
gMVP		0.36

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.75		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.75		Position offset: 13

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

Publications

LitVar

Other links and lift over

dbSNP: rs199848388; hg19: chr16-2135245;