rs1555506559

chr16-2072331-G-Achr16-2072331-G-Cchr16-2072331-G-T

Variant summary

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

The NM_000548.5(TSC2):c.2188G>A(p.Val730Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. V730A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.42

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]

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	UniProt
TSC2	NM_000548.5	c.2188G>A	p.Val730Met	missense_variant	20/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.2188G>A	p.Val730Met	missense_variant	20/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 05, 2023

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. 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. ClinVar contains an entry for this variant (Variation ID: 467929). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 730 of the TSC2 protein (p.Val730Met). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 30, 2022

The p.V730M variant (also known as c.2188G>A), located in coding exon 19 of the TSC2 gene, results from a G to A substitution at nucleotide position 2188. The valine at codon 730 is replaced by methionine, 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 v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
Cadd	Benign	22
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.55	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.13
Eigen_PC	Benign	-0.13
FATHMM_MKL	Benign	0.71	D
LIST_S2	Uncertain	0.90	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Uncertain	0.48	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Benign	1.0	L;.;.;.;L;L;.;.;.;L;.;L;.;.;.
MutationTaster	Benign	0.95	N;N;N;N;N;N;N
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-1.2	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.56
Sift	Uncertain	0.022	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Benign	0.23	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		0.88	P;.;.;.;P;B;.;.;P;B;.;.;.;.;.
Vest4		0.66
MutPred		0.78		Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);.;Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);.;Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);Gain of helix (P = 0.1736);.;
MVP		0.79
ClinPred		0.32	T
GERP RS		4.2
Varity_R		0.11
gMVP		0.33

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555506559; hg19: chr16-2122332;